This is related to D94982. We want to call these APIs from the Analysis
component, so we can't leave them under Transforms.
Differential Revision: https://reviews.llvm.org/D95079
Branch/assume conditions in PredicateInfo are currently handled in
a rather ad-hoc manner, with some arbitrary limitations. For example,
an `and` of two `icmp`s will be handled, but an `and` of an `icmp`
and some other condition will not. That also includes the case where
more than two conditions and and'ed together.
This patch makes the handling more general by looking through and/ors
up to a limit and considering all kinds of conditions (though operands
will only be taken for cmps of course).
Differential Revision: https://reviews.llvm.org/D94447
When using 2 InlinePass instances in the same CGSCC - one for other
mandatory inlinings, the other for the heuristic-driven ones - the order
in which the ImportedFunctionStats would be output-ed would depend on
the destruction order of the inline passes, which is not deterministic.
This patch moves the ImportedFunctionStats responsibility to the
InlineAdvisor to address this problem.
Differential Revision: https://reviews.llvm.org/D94982
Loop peeling assumes that the loop's latch is a conditional branch. Add
a check to canPeel that explicitly checks for this, and testcases that
otherwise fail an assertion when trying to peel a loop whose back-edge
is a switch case or the non-unwind edge of an invoke.
Reviewed By: skatkov, fhahn
Differential Revision: https://reviews.llvm.org/D94995
D84108 exposed a bad interaction between inlining and loop-rotation
during regular LTO, which is causing notable regressions in at least
CINT2006/473.astar.
The problem boils down to: we now rotate a loop just before the vectorizer
which requires duplicating a function call in the preheader when compiling
the individual files ('prepare for LTO'). But this then prevents further
inlining of the function during LTO.
This patch tries to resolve this issue by making LoopRotate more
conservative with respect to rotating loops that have inline-able calls
during the 'prepare for LTO' stage.
I think this change intuitively improves the current situation in
general. Loop-rotate tries hard to avoid creating headers that are 'too
big'. At the moment, it assumes all inlining already happened and the
cost of duplicating a call is equal to just doing the call. But with LTO,
inlining also happens during full LTO and it is possible that a previously
duplicated call is actually a huge function which gets inlined
during LTO.
From the perspective of LV, not much should change overall. Most loops
calling user-provided functions won't get vectorized to start with
(unless we can infer that the function does not touch memory, has no
other side effects). If we do not inline the 'inline-able' call during
the LTO stage, we merely delayed loop-rotation & vectorization. If we
inline during LTO, chances should be very high that the inlined code is
itself vectorizable or the user call was not vectorizable to start with.
There could of course be scenarios where we inline a sufficiently large
function with code not profitable to vectorize, which would have be
vectorized earlier (by scalarzing the call). But even in that case,
there probably is no big performance impact, because it should be mostly
down to the cost-model to reject vectorization in that case. And then
the version with scalarized calls should also not be beneficial. In a way,
LV should have strictly more information after inlining and make more
accurate decisions (barring cost-model issues).
There is of course plenty of room for things to go wrong unexpectedly,
so we need to keep a close look at actual performance and address any
follow-up issues.
I took a look at the impact on statistics for
MultiSource/SPEC2000/SPEC2006. There are a few benchmarks with fewer
loops rotated, but no change to the number of loops vectorized.
Reviewed By: sanwou01
Differential Revision: https://reviews.llvm.org/D94232
This patch teaches SimplifyCFG::SimplifyBranchOnICmpChain to understand select form of
(x == C1 || x == C2 || ...) / (x != C1 && x != C2 && ...) and optimize them into switch if possible.
D93065 has more context about the transition, including links to the list of optimizations being updated.
Differential Revision: https://reviews.llvm.org/D93943
This patch adds the default value of 1 to drop_begin.
In the llvm codebase, 70% of calls to drop_begin have 1 as the second
argument. The interface similar to with std::next should improve
readability.
This patch converts a couple of calls to drop_begin as examples.
Differential Revision: https://reviews.llvm.org/D94858
This patch marks some library functions as willreturn. On the first pass, I
excluded most functions that interact with streams/the filesystem.
Along with willreturn, it also adds nounwind to a set of math functions.
There probably are a few additional attributes we can add for those, but
that should be done separately.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D94684
When removing catchpad's from catchswitch, if that removes a successor,
we need to record that in DomTreeUpdater.
This fixes PostDomTree preservation failure in an existing test.
This appears to be the single issue that i see in my current test coverage.
DestBB might or might not already be a successor of SelectBB,
and it wasn't we need to ensure that we record the fact in DomTree.
The testcase used to crash in lazy domtree updater mode + non-per-function
domtree validity checks disabled.
This is not nice, but it's the best transient solution possible,
and is better than just duplicating the whole function.
The problem is, this function is widely used,
and it is not at all obvious that all the users
could be painlessly switched to operate on DomTreeUpdater,
and somehow i don't feel like porting all those users first.
This function is one of last three that not operate on DomTreeUpdater.
This is not nice, but it's the best transient solution possible,
and is better than just duplicating the whole function.
The problem is, this function is widely used,
and it is not at all obvious that all the users
could be painlessly switched to operate on DomTreeUpdater,
and somehow i don't feel like porting all those users first.
This function is one of last three that not operate on DomTreeUpdater.
This is not nice, but it's the best transient solution possible,
and is better than just duplicating the whole function.
The problem is, this function is widely used,
and it is not at all obvious that all the users
could be painlessly switched to operate on DomTreeUpdater,
and somehow i don't feel like porting all those users first.
This function is one of last three that not operate on DomTreeUpdater.
Even though not all it's users operate on DomTreeUpdater,
it itself internally operates on DomTreeUpdater,
so it must mean everything is fine with that,
so just do that globally.
Adding sample-profile-suffix-elision-policy attribute to functions whose linkage names are uniquefied so that their unique name suffix won't be trimmed when applying AutoFDO profiles.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D94455
LoopVectorize uses some utilities on LoopVersioning, but doesn't actually use it for, you know, versioning. As a result, the precondition LoopVersioning expects is too strong for this user. At the moment, LoopVectorize supports any loop with a unique exit block, so check the same precondition here.
Really, the whole class structure here is a mess. We should separate the actual versioning from the metadata updates, but that's a bigger problem.
When DomTreeUpdater is in lazy update mode, the blocks
that were scheduled to be removed, won't be removed
until the updates are flushed, e.g. by asking
DomTreeUpdater for a up-to-date DomTree.
From the function's current code, it is pretty evident
that the support for the lazy mode is an afterthought,
see e.g. how we roll-back NumRemoved statistic..
So instead of considering all the unreachable blocks
as the blocks-to-be-removed, simply additionally skip
all the blocks that are already scheduled to be removed
When we are adding edges to the terminator and potentially turning it
into a switch (if it wasn't already), it is possible that the
case we're adding will share it's destination with one of the
preexisting cases, in which case there is no domtree edge to add.
Indeed, this change does not have a test coverage change.
This failure has been exposed in an existing test coverage
by a follow-up patch that switches to lazy domtreeupdater mode,
and removes domtree verification from
SimplifyCFGOpt::simplifyOnce()/SimplifyCFGOpt::run(),
IOW it does not appear feasible to add dedicated test coverage here.
BB was already always branching to EdgeBB, there is no edge to add.
Indeed, this change does not have a test coverage change.
This failure has been exposed in an existing test coverage
by a follow-up patch that switches to lazy domtreeupdater mode,
and removes domtree verification from
SimplifyCFGOpt::simplifyOnce()/SimplifyCFGOpt::run(),
IOW it does not appear feasible to add dedicated test coverage here.
SI is the terminator of BB, so the edge we are adding obviously already existed.
Indeed, this change does not have a test coverage change.
This failure has been exposed in an existing test coverage
by a follow-up patch that switches to lazy domtreeupdater mode,
and removes domtree verification from
SimplifyCFGOpt::simplifyOnce()/SimplifyCFGOpt::run(),
IOW it does not appear feasible to add dedicated test coverage here.
Functions that are renamed under -funique-internal-linkage-names have their debug linkage name updated as well.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D93747
Please see D93747 for more context which tries to make linkage names of internal
linkage functions to be the uniqueified names. This causes a problem with gdb
because breaking using the demangled function name will not work if the new
uniqueified name cannot be demangled. The problem is the generated suffix which
is a mix of integers and letters which do not demangle. The demangler accepts
either all numbers or all letters. This patch simply converts the hash to decimal.
There is no loss of uniqueness by doing this as the precision is maintained.
The symbol names get longer by a few characters though.
Differential Revision: https://reviews.llvm.org/D94154
Loop peeling as a last step triggers loop simplification and this
can change the loop structure. As a result all cashed values like
latch branch becomes invalid.
Patch re-structure the code to take into account the possible
changes caused by peeling.
Reviewers: dmgreen, Meinersbur, etiotto, fhahn, efriedma, bmahjour
Reviewed By: Meinersbur, fhahn
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D93686
This is a resubmit of dd6bb367 (which was reverted due to stage2 build failures in 7c63aac), with the additional restriction added to the transform to only consider outer most loops.
As shown in the added test case, ensuring LCSSA is up to date when deleting an inner loop is tricky as we may actually need to remove blocks from any outer loops, thus changing the exit block set. For the moment, just avoid transforming this case. I plan to return to this case in a follow up patch and see if we can do better.
Original commit message follows...
The basic idea is that if SCEV can prove the backedge isn't taken, we can go ahead and get rid of the backedge (and thus the loop) while leaving the rest of the control in place. This nicely handles cases with dispatch between multiple exits and internal side effects.
Differential Revision: https://reviews.llvm.org/D93906
Currently make_early_inc_range cannot be used with iterators with
operator* implementations that do not return a reference.
Most notably in the LLVM codebase, this means the User iterator ranges
cannot be used with make_early_inc_range, which slightly simplifies
iterating over ranges while elements are removed.
Instead of directly using BaseT::reference as return type of operator*,
this patch uses decltype to get the actual return type of the operator*
implementation in WrappedIteratorT.
This patch also updates a few places to use make use of
make_early_inc_range.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D93992
Currently SimplifyCFG drops the debug locations of 'bonus' instructions.
Such instructions are moved before the first branch. The reason for the
current behavior is that this could lead to surprising debug stepping,
if the block that's folded is dead.
In case the first branch and the instructions to be folded have the same
debug location, this shouldn't be an issue and we can keep the debug
location.
Reviewed By: vsk
Differential Revision: https://reviews.llvm.org/D93662
We have modules with metadata on declarations, and out-of-tree passes
use that metadata, and we need to clone those modules. We really expect
such metadata is kept during the clone operation.
Reviewed by: arsenm, aprantl
Differential Revision: https://reviews.llvm.org/D93451
We need to handle this case before dealing with the case of constant
branch condition, because if the destinations match, latter fold
would try to remove the DomTree edge that would still be present.
This allows to make that particular DomTree update non-permissive
I have added it in d15d81c because it *seemed* correct, was holding
for all the tests so far, and was validating the fix added in the same
commit, but as David Major is pointing out (with a reproducer),
the assertion isn't really correct after all. So remove it.
Note that the d15d81c still fine.
Summary:
Currently SplitEdge does not support passing in parameter which allows you to
name the newly created BasicBlock.
This patch updates the function such that the name of the block can be passed
in, if users of this utility decide to do so.
Reviewed By: Whitney, bmahjour, asbirlea, jamieschmeiser
Differential Revision: https://reviews.llvm.org/D94176
Add support for mixed pre/post CFG views.
Update usages of the MemorySSAUpdater to use the new DT API by
requesting the DT updates to be done by the MSSAUpdater.
Differential Revision: https://reviews.llvm.org/D93371
Previously when trying to support CoroSplit's function splitting, we
added in a hack that simply added the new function's node into the
original function's SCC (https://reviews.llvm.org/D87798). This is
incorrect since it might be in its own SCC.
Now, more similar to the previous design, we have callers explicitly
notify the LazyCallGraph that a function has been split out from another
one.
In order to properly support CoroSplit, there are two ways functions can
be split out.
One is the normal expected "outlining" of one function into a new one.
The new function may only contain references to other functions that the
original did. The original function must reference the new function. The
new function may reference the original function, which can result in
the new function being in the same SCC as the original function. The
weird case is when the original function indirectly references the new
function, but the new function directly calls the original function,
resulting in the new SCC being a parent of the original function's SCC.
This form of function splitting works with CoroSplit's Switch ABI.
The second way of splitting is more specific to CoroSplit. CoroSplit's
Retcon and Async ABIs split the original function into multiple
functions that all reference each other and are referenced by the
original function. In order to keep the LazyCallGraph in a valid state,
all new functions must be processed together, else some nodes won't be
populated. To keep things simple, this only supports the case where all
new edges are ref edges, and every new function references every other
new function. There can be a reference back from any new function to the
original function, putting all functions in the same RefSCC.
This also adds asserts that all nodes in a (Ref)SCC can reach all other
nodes to prevent future incorrect hacks.
The original hacks in https://reviews.llvm.org/D87798 are no longer
necessary since all new functions should have been registered before
calling updateCGAndAnalysisManagerForPass.
This fixes all coroutine tests when opt's -enable-new-pm is true by
default. This also fixes PR48190, which was likely due to the previous
hack breaking SCC invariants.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D93828
* Update valueCoversEntireFragment to use TypeSize.
* Add a regression test.
* Assertions have been added to protect untested codepaths.
Reviewed By: sdesmalen
Differential Revision: https://reviews.llvm.org/D91806
If the predecessor is a switch, and BB is not the default destination,
multiple cases could have the same destination. and it doesn't
make sense to re-process the predecessor, because we won't make any changes,
once is enough.
I'm not sure this can be really tested, other than via the assertion
being added here, which fires without the fix.
One would hope that it would have been already canonicalized into an
unconditional branch, but that isn't really guaranteed to happen
with SimplifyCFG's visitation order.
... which requires not removing a DomTree edge if the switch's default
still points at that destination, because it can't be removed;
... and not processing the same predecessor more than once.
From C11 and C++11 onwards, a forward-progress requirement has been
introduced for both languages. In the case of C, loops with non-constant
conditionals that do not have any observable side-effects (as defined by
6.8.5p6) can be assumed by the implementation to terminate, and in the
case of C++, this assumption extends to all functions. The clang
frontend will emit the `mustprogress` function attribute for C++
functions (D86233, D85393, D86841) and emit the loop metadata
`llvm.loop.mustprogress` for every loop in C11 or later that has a
non-constant conditional.
This patch modifies LoopDeletion so that only loops with
the `llvm.loop.mustprogress` metadata or loops contained in functions
that are required to make progress (`mustprogress` or `willreturn`) are
checked for observable side-effects. If these loops do not have an
observable side-effect, then we delete them.
Loops without observable side-effects that do not satisfy the above
conditions will not be deleted.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86844
... which requires not deleting an edge that just got deleted,
because we could be dealing with a block that didn't go through
ConstantFoldTerminator() yet, and thus has a degenerate cond br
with matching true/false destinations.
Notably, this doesn't switch *every* case, remaining cases
don't actually pass sanity checks in non-permissve mode,
and therefore require further analysis.
Note that SimplifyCFG still defaults to not preserving DomTree by default,
so this is effectively a NFC change.
While here, rename the inaccurate getRecurrenceBinOp()
because that was also used to get CmpInst opcodes.
The recurrence/reduction kind should always refer to the
expected opcode for a reduction. SLP appears to be the
only direct caller of createSimpleTargetReduction(), and
that calling code ideally should not be carrying around
both an opcode and a reduction kind.
This should allow us to generalize reduction matching to
use intrinsics instead of only binops.
Allow loop nests with empty basic blocks without loops in different
levels as perfect.
Reviewers: Meinersbur
Differential Revision: https://reviews.llvm.org/D93665
This reverts commit dd6bb367d1.
Multi-stage builders are showing an assertion failure w/LCSSA not being preserved on entry to IndVars. Reason isn't clear, reverting while investigating.
The basic idea is that if SCEV can prove the backedge isn't taken, we can go ahead and get rid of the backedge (and thus the loop) while leaving the rest of the control in place. This nicely handles cases with dispatch between multiple exits and internal side effects.
Differential Revision: https://reviews.llvm.org/D93906
This is NFC since SimplifyCFG still currently defaults to not preserving DomTree.
SimplifyCFGOpt::simplifyOnce() is only be called from SimplifyCFGOpt::run(),
and can not be called externally, since SimplifyCFGOpt is defined in .cpp
This avoids some needless verifications, and is thus a bit faster
without sacrificing precision.
We only need to remove non-TrueBB/non-FalseBB successors,
and we only need to do that once. We don't need to insert
any new edges, because no new successors will be added.
There is a number of transforms in SimplifyCFG that take DomTree out of
DomTreeUpdater, and do updates manually. Until they are fixed,
user passes are unable to claim that PDT is preserved.
Note that the default for SimplifyCFG is still not to preserve DomTree,
so this is still effectively NFC.
This is almost all mechanical search-and-replace and
no-functional-change-intended (NFC). Having a single
enum makes it easier to match/reason about the
reduction cases.
The goal is to remove `Opcode` from reduction matching
code in the vectorizers because that makes it harder to
adapt the code to handle intrinsics.
The code in RecurrenceDescriptor::AddReductionVar() is
the only place that required closer inspection. It uses
a RecurrenceDescriptor and a second InstDesc to sometimes
overwrite part of the struct. It seem like we should be
able to simplify that logic, but it's not clear exactly
which cmp+sel patterns that we are trying to handle/avoid.
This pretty much concludes patch series for updating SimplifyCFG
to preserve DomTree. All 318 dedicated `-simplifycfg` tests now pass
with `-simplifycfg-require-and-preserve-domtree=1`.
There are a few leftovers that apparently don't have good test coverage.
I do not yet know what gaps in test coverage will the wider-scale testing
reveal, but the default flip might be close.
Test clang/test/Misc/loop-opt-setup.c fails when executed in Release.
This reverts commit 6f1503d598.
Reviewed By: SureYeaah
Differential Revision: https://reviews.llvm.org/D93956
From C11 and C++11 onwards, a forward-progress requirement has been
introduced for both languages. In the case of C, loops with non-constant
conditionals that do not have any observable side-effects (as defined by
6.8.5p6) can be assumed by the implementation to terminate, and in the
case of C++, this assumption extends to all functions. The clang
frontend will emit the `mustprogress` function attribute for C++
functions (D86233, D85393, D86841) and emit the loop metadata
`llvm.loop.mustprogress` for every loop in C11 or later that has a
non-constant conditional.
This patch modifies LoopDeletion so that only loops with
the `llvm.loop.mustprogress` metadata or loops contained in functions
that are required to make progress (`mustprogress` or `willreturn`) are
checked for observable side-effects. If these loops do not have an
observable side-effect, then we delete them.
Loops without observable side-effects that do not satisfy the above
conditions will not be deleted.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86844
I don't know if there's some way this changes what the vectorizers
may produce for reductions, but I have added test coverage with
3567908 and 5ced712 to show that both passes already have bugs in
this area. Hopefully this does not make things worse before we can
really fix it.
This is no-functional-change-intended (AFAIK, we can't
isolate this difference in a regression test).
That's because the callers should be setting the IRBuilder's
FMF field when creating the reduction and/or setting those
flags after creating. It doesn't make sense to override this
one flag alone.
This is part of a multi-step process to clean up the FMF
setting/propagation. See PR35538 for an example.
As mentioned in D93793, there are quite a few places where unary `IRBuilder::CreateShuffleVector(X, Mask)` can be used
instead of `IRBuilder::CreateShuffleVector(X, Undef, Mask)`.
Let's update them.
Actually, it would have been more natural if the patches were made in this order:
(1) let them use unary CreateShuffleVector first
(2) update IRBuilder::CreateShuffleVector to use poison as a placeholder value (D93793)
The order is swapped, but in terms of correctness it is still fine.
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D93923
The switch duplicated the translation in getRecurrenceBinOp().
This code is still weird because it translates to the TTI
ReductionFlags for min/max, but then createSimpleTargetReduction()
converts that back to RecurrenceDescriptor::MinMaxRecurrenceKind.
We might be dealing with an unreachable code,
so the bonus instruction we clone might be self-referencing.
There is a sanity check that all uses of bonus instructions
that are not in the original block with said bonus instructions
are PHI nodes, and that is obviously not the case
for self-referencing instructions..
So if we find such an use, just rewrite it.
Thanks to Mikael Holmén for the reproducer!
Fixes https://bugs.llvm.org/show_bug.cgi?id=48450#c8
The function FoldSingleEntryPHINodes() is changed to return if
it has changed IR or not. This return value is used by RS4GC to
set the MadeChange flag respectively.
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D93810
Previously the branch from the middle block to the scalar preheader & exit
was being set-up at the end of skeleton creation in completeLoopSkeleton.
Inserting SCEV or runtime checks may result in LCSSA phis being created,
if they are required. Adjusting branches afterwards may break those
PHIs.
To avoid this, we can instead create the branch from the middle block
to the exit after we created the middle block, so we have the final CFG
before potentially adjusting/creating PHIs.
This fixes a crash for the included test case. For the non-crashing
case, this is almost a NFC with respect to the generated code. The
only change is the order of the predecessors of the involved branch
targets.
Note an assertion was moved from LoopVersioning() to
LoopVersioning::versionLoop. Adjusting the branches means loop-simplify
form may be broken before constructing LoopVersioning. But LV only uses
LoopVersioning to annotate the loop instructions with !noalias metadata,
which does not require loop-simplify form.
This is a fix for an existing issue uncovered by D93317.
... so just ensure that we pass DomTreeUpdater it into it.
Apparently, there were no dedicated tests just for that functionality,
so i'm adding one here.
And that exposes that a number of tests don't *actually* manage to
maintain DomTree validity, which is inline with my observations.
Once again, SimlifyCFG pass currently does not require/preserve DomTree
by default, so this is effectively NFC.
This PR implements the function splitBasicBlockBefore to address an
issue
that occurred during SplitEdge(BB, Succ, ...), inside splitBlockBefore.
The issue occurs in SplitEdge when the Succ has a single predecessor
and the edge between the BB and Succ is not critical. This produces
the result ‘BB->Succ->New’. The new function splitBasicBlockBefore
was added to splitBlockBefore to handle the issue and now produces
the correct result ‘BB->New->Succ’.
Below is an example of splitting the block bb1 at its first instruction.
/// Original IR
bb0:
br bb1
bb1:
%0 = mul i32 1, 2
br bb2
bb2:
/// IR after splitEdge(bb0, bb1) using splitBasicBlock
bb0:
br bb1
bb1:
br bb1.split
bb1.split:
%0 = mul i32 1, 2
br bb2
bb2:
/// IR after splitEdge(bb0, bb1) using splitBasicBlockBefore
bb0:
br bb1.split
bb1.split
br bb1
bb1:
%0 = mul i32 1, 2
br bb2
bb2:
Differential Revision: https://reviews.llvm.org/D92200
Pretty boring, removeUnwindEdge() already known how to update DomTree,
so if we are to call it, we must first flush our own pending updates;
otherwise, we just stop predecessors from branching to us,
and for certain predecessors, stop their predecessors from
branching to them also.
... so just ensure that we pass DomTreeUpdater it into it.
Fixes DomTree preservation for a number of tests,
all of which are marked as such so that they do not regress.
... so just ensure that we pass DomTreeUpdater it into it.
Fixes DomTree preservation for a large number of tests,
all of which are marked as such so that they do not regress.
The LCSSA pass makes use of a function insertDebugValuesForPHIs() to
propogate dbg.value() intrinsics to newly inserted PHI instructions. Faulty
behaviour occurs when the parent PHI of a newly inserted PHI is not the
most recent assignment to a source variable. insertDebugValuesForPHIs ends
up propagating a value that isn't the most recent assignemnt.
This change removes the call to insertDebugValuesForPHIs() from LCSSA,
preventing incorrect dbg.value intrinsics from being propagated.
Propagating variable locations between blocks will occur later, during
LiveDebugValues.
Differential Revision: https://reviews.llvm.org/D92576
This PR implements the function splitBasicBlockBefore to address an
issue
that occurred during SplitEdge(BB, Succ, ...), inside splitBlockBefore.
The issue occurs in SplitEdge when the Succ has a single predecessor
and the edge between the BB and Succ is not critical. This produces
the result ‘BB->Succ->New’. The new function splitBasicBlockBefore
was added to splitBlockBefore to handle the issue and now produces
the correct result ‘BB->New->Succ’.
Below is an example of splitting the block bb1 at its first instruction.
/// Original IR
bb0:
br bb1
bb1:
%0 = mul i32 1, 2
br bb2
bb2:
/// IR after splitEdge(bb0, bb1) using splitBasicBlock
bb0:
br bb1
bb1:
br bb1.split
bb1.split:
%0 = mul i32 1, 2
br bb2
bb2:
/// IR after splitEdge(bb0, bb1) using splitBasicBlockBefore
bb0:
br bb1.split
bb1.split
br bb1
bb1:
%0 = mul i32 1, 2
br bb2
bb2:
Differential Revision: https://reviews.llvm.org/D92200
When folding a branch to a common destination, preserve !annotation on
the created instruction, if the terminator of the BB that is going to be
removed has !annotation. This should ensure that !annotation is attached
to the instructions that 'replace' the original terminator.
Reviewed By: jdoerfert, lebedev.ri
Differential Revision: https://reviews.llvm.org/D93410
... so just ensure that we pass DomTreeUpdater it into it.
Fixes DomTree preservation for a large number of tests,
all of which are marked as such so that they do not regress.
... so just ensure that we pass DomTreeUpdater it into it.
Fixes DomTree preservation for a large number of tests,
all of which are marked as such so that they do not regress.
This PR implements the function splitBasicBlockBefore to address an
issue
that occurred during SplitEdge(BB, Succ, ...), inside splitBlockBefore.
The issue occurs in SplitEdge when the Succ has a single predecessor
and the edge between the BB and Succ is not critical. This produces
the result ‘BB->Succ->New’. The new function splitBasicBlockBefore
was added to splitBlockBefore to handle the issue and now produces
the correct result ‘BB->New->Succ’.
Below is an example of splitting the block bb1 at its first instruction.
/// Original IR
bb0:
br bb1
bb1:
%0 = mul i32 1, 2
br bb2
bb2:
/// IR after splitEdge(bb0, bb1) using splitBasicBlock
bb0:
br bb1
bb1:
br bb1.split
bb1.split:
%0 = mul i32 1, 2
br bb2
bb2:
/// IR after splitEdge(bb0, bb1) using splitBasicBlockBefore
bb0:
br bb1.split
bb1.split
br bb1
bb1:
%0 = mul i32 1, 2
br bb2
bb2:
Differential Revision: https://reviews.llvm.org/D92200
Two observations:
1. Unavailability of DomTree makes it impossible to make
`FoldBranchToCommonDest()` transform in certain cases,
where the successor is dominated by predecessor,
because we then don't have PHI's, and can't recreate them,
well, without handrolling 'is dominated by' check,
which doesn't really look like a great solution to me.
2. Avoiding invalidating DomTree in SimplifyCFG will
decrease the number of `Dominator Tree Construction` by 5
(from 28 now, i.e. -18%) in `-O3` old-pm pipeline
(as per `llvm/test/Other/opt-O3-pipeline.ll`)
This might or might not be beneficial for compile time.
So the plan is to make SimplifyCFG preserve DomTree, and then
eventually make DomTree fully required and preserved by the pass.
Now, SimplifyCFG is ~7KLOC. I don't think it will be nice
to do all this uplifting in a single mega-commit,
nor would it be possible to review it in any meaningful way.
But, i believe, it should be possible to do this in smaller steps,
introducing the new behavior, in an optional way, off-by-default,
opt-in option, and gradually fixing transforms one-by-one
and adding the flag to appropriate test coverage.
Then, eventually, the default should be flipped,
and eventually^2 the flag removed.
And that is what is happening here - when the new off-by-default option
is specified, DomTree is required and is claimed to be preserved,
and SimplifyCFG-internal assertions verify that the DomTree is still OK.
his is a preparation patch for supporting multiple exits in the loop vectorizer, by itself it should be mostly NFC. This patch moves the loop structure checks from LAA to their respective consumers (where duplicates don't already exist). Moving the checks does end up changing some of the optimization warnings and debug output slightly, but nothing that appears to be a regression.
Why do this? Well, after auditing the code, I can't actually find anything in LAA itself which relies on having all instructions within a loop execute an equal number of times. This patch simply makes this explicit so that if one consumer - say LV in the near future (hopefully) - wants to handle a broader class of loops, it can do so.
Differential Revision: https://reviews.llvm.org/D92066
Even though d38205144f was mostly a correct
fix for the external non-PHI users, it's not a *generally* correct fix,
because the 'placeholder' values in those trivial PHI's we create
shouldn't be *always* 'undef', but the PHI itself for the backedges,
else we end up with wrong value, as the `@pr48450_2` test shows.
But we can't just do that, because we can't check that the PHI
can be it's own incoming value when coming from certain predecessor,
because we don't have a dominator tree.
So until we can address this correctness problem properly,
ensure that we don't perform the transformation
if there are such problematic external uses.
Making dominator tree available there is going to be involved,
since `-simplifycfg` pass currently does not preserve/update domtree...
In particular, if the successor block, which is about to get a new
predecessor block, currently only has a single predecessor,
then the bonus instructions will be directly used within said successor,
which is fine, since the block with bonus instructions dominates that
successor. But once there's a new predecessor, the IR is no longer valid,
and we don't fix it, because we only update PHI nodes.
Which means, the live-out bonus instructions must be exclusively used
by the PHI nodes in successor blocks. So we have to form trivial PHI nodes.
which will then be successfully updated to recieve cloned bonus instns.
This all works fine, except for the fact that we don't have access to
the dominator tree, and we don't ignore unreachable code,
so we sometimes do end up having to deal with some weird IR.
Fixes https://bugs.llvm.org/show_bug.cgi?id=48450
This migrates all LLVM (except Kaleidoscope and
CodeGen/StackProtector.cpp) DebugLoc::get to DILocation::get.
The CodeGen/StackProtector.cpp usage may have a nullptr Scope
and can trigger an assertion failure, so I don't migrate it.
Reviewed By: #debug-info, dblaikie
Differential Revision: https://reviews.llvm.org/D93087
I'm not sure if it would be legal by the IR reference to introduce
an addrspacecast here, since the IR reference is a bit vague on
the exact semantics, but at least for our usage of it (and I
suspect for many other's usage) it is not. For us, addrspacecasts
between non-integral address spaces carry frontend information that the
optimizer cannot deduce afterwards in a generic way (though we
have frontend specific passes in our pipline that do propagate
these). In any case, I'm sure nobody is using it this way at
the moment, since it would have introduced inttoptrs, which
are definitely illegal.
Fixes PR38375
Co-authored-by: Keno Fischer <keno@alumni.harvard.edu>
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D50010
This reverts commit 4bd35cdc3a.
The patch was reverted during the investigation. The investigation
shown that the patch did not cause any trouble, but just exposed
the existing problem that is addressed by the previous patch
"[IndVars] Quick fix LHS/RHS bug". Returning without changes.
The code relies on fact that LHS is the NarrowDef but never
really checks it. Adding the conservative restrictive check,
will follow-up with handling of case where RHS is a NarrowDef.
1. Removed #include "...AliasAnalysis.h" in other headers and modules.
2. Cleaned up includes in AliasAnalysis.h.
Reviewed By: RKSimon
Differential Revision: https://reviews.llvm.org/D92489
This reverts commit 0c9c6ddf17.
We are seeing some failures with this patch locally. Not clear
if it's causing them or just triggering a problem in another
place. Reverting while investigating.
In this patch I have added support for a new loop hint called
vectorize.scalable.enable that says whether we should enable scalable
vectorization or not. If a user wants to instruct the compiler to
vectorize a loop with scalable vectors they can now do this as
follows:
br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !2
...
!2 = !{!2, !3, !4}
!3 = !{!"llvm.loop.vectorize.width", i32 8}
!4 = !{!"llvm.loop.vectorize.scalable.enable", i1 true}
Setting the hint to false simply reverts the behaviour back to the
default, using fixed width vectors.
Differential Revision: https://reviews.llvm.org/D88962
There is no correctness need for that, and since we allow live-out
uses, this could theoretically happen, because currently nothing
will move the cond to right before the branch in those tests.
But regardless, lifting that restriction even makes the transform
easier to understand.
This makes the transform happen in 81 more cases (+0.55%)
)
If we decided to widen IV with zext, then unsigned comparisons
should not prevent widening (same for sext/sign comparisons).
The result of comparison in wider type does not change in this case.
Differential Revision: https://reviews.llvm.org/D92207
Reviewed By: nikic
This was orginally committed in 2245fb8aaa.
but was immediately reverted in f3abd54958
because of a PHI handling issue.
Original commit message:
1. It doesn't make sense to enforce that the bonus instruction
is only used once in it's basic block. What matters is
whether those user instructions fit within our budget, sure,
but that is another question.
2. It doesn't make sense to enforce that said bonus instructions
are only used within their basic block. Perhaps the branch
condition isn't using the value computed by said bonus instruction,
and said bonus instruction is simply being calculated
to be used in successors?
So iff we can clone bonus instructions, to lift these restrictions,
we just need to carefully update their external uses
to use the new cloned instructions.
Notably, this transform (even without this change) appears to be
poison-unsafe as per alive2, but is otherwise (including the patch) legal.
We don't introduce any new PHI nodes, but only "move" the instructions
around, i'm not really seeing much potential for extra cost modelling
for the transform, especially since now we allow at most one such
bonus instruction by default.
This causes the fold to fire +11.4% more (13216 -> 14725)
as of vanilla llvm test-suite + RawSpeed.
The motivational pattern is IEEE-754-2008 Binary16->Binary32
extension code:
ca57d77fb2/src/librawspeed/common/FloatingPoint.h (L115-L120)
^ that should be a switch, but it is not now: https://godbolt.org/z/bvja5v
That being said, even thought this seemed like this would fix it: https://godbolt.org/z/xGq3TM
apparently that fold is happening somewhere else afterall,
so something else also has a similar 'artificial' restriction.
When widening an IndVar that has LCSSA Phi users outside
the loop, we can safely widen it as usual and then truncate
the result outside the loop without hurting the performance.
Differential Revision: https://reviews.llvm.org/D91593
Reviewed By: skatkov
Many bots are unhappy, at the very least missed a few codegen tests,
and possibly this has a logic hole inducing a miscompile
(will be really awesome to have ready reproducer..)
Need to investigate.
This reverts commit 2245fb8aaa.
1. It doesn't make sense to enforce that the bonus instruction
is only used once in it's basic block. What matters is
whether those user instructions fit within our budget, sure,
but that is another question.
2. It doesn't make sense to enforce that said bonus instructions
are only used within their basic block. Perhaps the branch
condition isn't using the value computed by said bonus instruction,
and said bonus instruction is simply being calculated
to be used in successors?
So iff we can clone bonus instructions, to lift these restrictions,
we just need to carefully update their external uses
to use the new cloned instructions.
Notably, this transform (even without this change) appears to be
poison-unsafe as per alive2, but is otherwise (including the patch) legal.
We don't introduce any new PHI nodes, but only "move" the instructions
around, i'm not really seeing much potential for extra cost modelling
for the transform, especially since now we allow at most one such
bonus instruction by default.
This causes the fold to fire +11.4% more (13216 -> 14725)
as of vanilla llvm test-suite + RawSpeed.
The motivational pattern is IEEE-754-2008 Binary16->Binary32
extension code:
ca57d77fb2/src/librawspeed/common/FloatingPoint.h (L115-L120)
^ that should be a switch, but it is not now: https://godbolt.org/z/bvja5v
That being said, even thought this seemed like this would fix it: https://godbolt.org/z/xGq3TM
apparently that fold is happening somewhere else afterall,
so something else also has a similar 'artificial' restriction.
When deciding to widen narrow use, we may need to prove some facts
about it. For proof, the context is used. Currently we take the instruction
being widened as the context.
However, we may be more precise here if we take as context the point that
dominates all users of instruction being widened.
Differential Revision: https://reviews.llvm.org/D90456
Reviewed By: skatkov
Some older code - and code copied from older code - still directly tested against the singelton result of SE::getCouldNotCompute. Using the isa<SCEVCouldNotCompute> form is both shorter, and more readable.
This change introduces a new IR intrinsic named `llvm.pseudoprobe` for pseudo-probe block instrumentation. Please refer to https://reviews.llvm.org/D86193 for the whole story.
A pseudo probe is used to collect the execution count of the block where the probe is instrumented. This requires a pseudo probe to be persisting. The LLVM PGO instrumentation also instruments in similar places by placing a counter in the form of atomic read/write operations or runtime helper calls. While these operations are very persisting or optimization-resilient, in theory we can borrow the atomic read/write implementation from PGO counters and cut it off at the end of compilation with all the atomics converted into binary data. This was our initial design and we’ve seen promising sample correlation quality with it. However, the atomics approach has a couple issues:
1. IR Optimizations are blocked unexpectedly. Those atomic instructions are not going to be physically present in the binary code, but since they are on the IR till very end of compilation, they can still prevent certain IR optimizations and result in lower code quality.
2. The counter atomics may not be fully cleaned up from the code stream eventually.
3. Extra work is needed for re-targeting.
We choose to implement pseudo probes based on a special LLVM intrinsic, which is expected to have most of the semantics that comes with an atomic operation but does not block desired optimizations as much as possible. More specifically the semantics associated with the new intrinsic enforces a pseudo probe to be virtually executed exactly the same number of times before and after an IR optimization. The intrinsic also comes with certain flags that are carefully chosen so that the places they are probing are not going to be messed up by the optimizer while most of the IR optimizations still work. The core flags given to the special intrinsic is `IntrInaccessibleMemOnly`, which means the intrinsic accesses memory and does have a side effect so that it is not removable, but is does not access memory locations that are accessible by any original instructions. This way the intrinsic does not alias with any original instruction and thus it does not block optimizations as much as an atomic operation does. We also assign a function GUID and a block index to an intrinsic so that they are uniquely identified and not merged in order to achieve good correlation quality.
Let's now look at an example. Given the following LLVM IR:
```
define internal void @foo2(i32 %x, void (i32)* %f) !dbg !4 {
bb0:
%cmp = icmp eq i32 %x, 0
br i1 %cmp, label %bb1, label %bb2
bb1:
br label %bb3
bb2:
br label %bb3
bb3:
ret void
}
```
The instrumented IR will look like below. Note that each `llvm.pseudoprobe` intrinsic call represents a pseudo probe at a block, of which the first parameter is the GUID of the probe’s owner function and the second parameter is the probe’s ID.
```
define internal void @foo2(i32 %x, void (i32)* %f) !dbg !4 {
bb0:
%cmp = icmp eq i32 %x, 0
call void @llvm.pseudoprobe(i64 837061429793323041, i64 1)
br i1 %cmp, label %bb1, label %bb2
bb1:
call void @llvm.pseudoprobe(i64 837061429793323041, i64 2)
br label %bb3
bb2:
call void @llvm.pseudoprobe(i64 837061429793323041, i64 3)
br label %bb3
bb3:
call void @llvm.pseudoprobe(i64 837061429793323041, i64 4)
ret void
}
```
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D86490
This is the same fix as 23aeadb89d,
just for CloneScopedAliasMetadata rather than PropagateCallSiteMetadata.
In this case the previous outcome was incorrectly dropped metadata,
as it was not part of the computed metadata map.
The real change in the test is that the first load now retains
metadata, the rest of the changes are due to changes in metadata
numbering.
The VMap also contains a mapping from Argument => Instruction,
where the instruction is part of the original function, not the
inlined one. The code was assuming that all the instructions in
the VMap were inlined.
This was a pre-existing problem for the loop access metadata, but
was extended to the more common noalias metadata by
27f647d117, thus causing miscompiles.
There is a similar assumption inside CloneAliasScopeMetadata(), so
that one likely needs to be fixed as well.
This wasn't properly remapping the type like with the other
attributes, so this would end up hitting a verifier error after
linking different modules using byref.
With a function pass manager, it would insert debuginfo metadata before
getting to function passes while processing the pass manager, causing
debugify to skip while running the function passes.
Skip special passes + verifier + printing passes. Compared to the legacy
implementation of -debugify-each, this additionally skips verifier
passes. Probably no need to update the legacy version since it will be
obsolete soon.
This fixes 2 instcombine tests using -debugify-each under NPM.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D91558
See discussion in https://bugs.llvm.org/show_bug.cgi?id=45073 / https://reviews.llvm.org/D66324#2334485
the implementation is known-broken for certain inputs,
the bugreport was up for a significant amount of timer,
and there has been no activity to address it.
Therefore, just completely rip out all of misexpect handling.
I suspect, fixing it requires redesigning the internals of MD_misexpect.
Should anyone commit to fixing the implementation problem,
starting from clean slate may be better anyways.
This reverts commit 7bdad08429,
and some of it's follow-ups, that don't stand on their own.
No longer rely on an external tool to build the llvm component layout.
Instead, leverage the existing `add_llvm_componentlibrary` cmake function and
introduce `add_llvm_component_group` to accurately describe component behavior.
These function store extra properties in the created targets. These properties
are processed once all components are defined to resolve library dependencies
and produce the header expected by llvm-config.
Differential Revision: https://reviews.llvm.org/D90848
Sometimes the an instruction we are trying to widen is used by the IV
(which means the instruction is the IV increment). Currently this may
prevent its widening. We should ignore such user because it will be
dead once the transform is done anyways.
Differential Revision: https://reviews.llvm.org/D90920
Reviewed By: fhahn
InstCombine canonicalizes 'sub nuw' instructions to 'add' without the
`nuw` flag. The typical case where we see it is decrementing induction
variables. For them, IndVars fails to prove that it's legal to widen them,
and inserts unprofitable `zext`'s.
This patch adds recognition of such pattern using SCEV.
Differential Revision: https://reviews.llvm.org/D89550
Reviewed By: fhahn, skatkov
This was missing as discovered by the SystemZ multistage bot:
http://lab.llvm.org:8011/#/builders/8, where wrong code resulted when this
extension was not performed.
Thanks for review by Ulrich Weigand and Roman Lebedev.
Differential Revision: https://reviews.llvm.org/D90760
We already do not unroll loops with vector instructions under MVE, but
that does not include the remainder loops that the vectorizer produces.
These remainder loops will be rarely executed and are not worth
unrolling, as the trip count is likely to be low if they get executed at
all. Luckily they get llvm.loop.isvectorized to make recognizing them
simpler.
We have wanted to do this for a while but hit issues with low overhead
loops being reverted due to difficult registry allocation. With recent
changes that seems to be less of an issue now.
Differential Revision: https://reviews.llvm.org/D90055
From C11 and C++11 onwards, a forward-progress requirement has been
introduced for both languages. In the case of C, loops with non-constant
conditionals that do not have any observable side-effects (as defined by
6.8.5p6) can be assumed by the implementation to terminate, and in the
case of C++, this assumption extends to all functions. The clang
frontend will emit the `mustprogress` function attribute for C++
functions (D86233, D85393, D86841) and emit the loop metadata
`llvm.loop.mustprogress` for every loop in C11 or later that has a
non-constant conditional.
This patch modifies LoopDeletion so that only loops with
the `llvm.loop.mustprogress` metadata or loops contained in functions
that are required to make progress (`mustprogress` or `willreturn`) are
checked for observable side-effects. If these loops do not have an
observable side-effect, then we delete them.
Loops without observable side-effects that do not satisfy the above
conditions will not be deleted.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86844
Currently, LoopDeletion refuses to remove dead loops with no exit blocks
because it cannot statically determine the control flow after it removes
the block. This leads to miscompiles if the loop is an infinite loop and
should've been removed.
Differential Revision: https://reviews.llvm.org/D90115
This moves WidenIV from IndVarSimplify to Utils/SimplifyIndVar so that we have
createWideIV available as a generic helper utility. I.e., this is not only
useful in IndVarSimplify, but could be useful for loop transformations. For
example, motivation for this refactoring is the loop flatten transformation: if
induction variables in a loop nest can be widened, we can avoid having to
perform certain overflow checks, enabling this transformation.
Differential Revision: https://reviews.llvm.org/D90421
There is already an API in BasicBlock that checks and returns the musttail call if it precedes the return instruction.
Use it instead of manually checking in each place.
Differential Revision: https://reviews.llvm.org/D90693
This reverts the revert commit 408c4408fa.
This version of the patch includes a fix for a crash caused by
treating ICmp/FCmp constant expressions as instructions.
Original message:
On some targets, like AArch64, vector selects can be efficiently lowered
if the vector condition is a compare with a supported predicate.
This patch adds a new argument to getCmpSelInstrCost, to indicate the
predicate of the feeding select condition. Note that it is not
sufficient to use the context instruction when querying the cost of a
vector select starting from a scalar one, because the condition of the
vector select could be composed of compares with different predicates.
This change greatly improves modeling the costs of certain
compare/select patterns on AArch64.
I am also planning on putting up patches to make use of the new argument in
SLPVectorizer & LV.
Previously, !noalias and !alias.scope metadata on the call site was
applied as part of CloneAliasScopeMetadata(), which short-circuits
if the callee does not use any noalias metadata itself. However,
these two things have no relation to each other.
Consistently apply !noalias and !alias.scope metadata by integrating
this into an existing function that handled !llvm.access.group and
!llvm.mem.parallel_loop_access metadata. The handling for all of
these metadata kinds essentially the same.
CallInst::updateProfWeight() creates branch_weights with i64 instead of i32.
To be more consistent everywhere and remove lots of casts from uint64_t
to uint32_t, use i64 for branch_weights.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D88609
This patch modifies two for loops to use the range based syntax.
Since they are equivalent, this patch is tagged NFC.
Differential Revision: https://reviews.llvm.org/D90069
On some targets, like AArch64, vector selects can be efficiently lowered
if the vector condition is a compare with a supported predicate.
This patch adds a new argument to getCmpSelInstrCost, to indicate the
predicate of the feeding select condition. Note that it is not
sufficient to use the context instruction when querying the cost of a
vector select starting from a scalar one, because the condition of the
vector select could be composed of compares with different predicates.
This change greatly improves modeling the costs of certain
compare/select patterns on AArch64.
I am also planning on putting up patches to make use of the new argument in
SLPVectorizer & LV.
Reviewed By: dmgreen, RKSimon
Differential Revision: https://reviews.llvm.org/D90070
And use it to model LLVM IR's `ptrtoint` cast.
This is essentially an alternative to D88806, but with no chance for
all the problems it caused due to having the cast as implicit there.
(see rG7ee6c402474a2f5fd21c403e7529f97f6362fdb3)
As we've established by now, there are at least two reasons why we want this:
* It will allow SCEV to actually model the `ptrtoint` casts
and their operands, instead of treating them as `SCEVUnknown`
* It should help with initial problem of PR46786 - this should eventually allow us
to not loose pointer-ness of an expression in more cases
As discussed in [[ https://bugs.llvm.org/show_bug.cgi?id=46786 | PR46786 ]], in principle,
we could just extend `SCEVUnknown` with a `is ptrtoint` cast, because `ScalarEvolution::getPtrToIntExpr()`
should sink the cast as far down into the expression as possible,
so in the end we should always end up with `SCEVPtrToIntExpr` of `SCEVUnknown`.
But i think that it isn't the best solution, because it doesn't really matter
from memory consumption side - there probably won't be *that* many `SCEVPtrToIntExpr`s
for it to matter, and it allows for much better discoverability.
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D89456
Use -0.0 instead of 0.0 as the start value. The previous use of 0.0
was fine for all existing uses of this function though, as it is
always generated with fast flags right now, and thus nsz.
This patch changes MergeBlockIntoPredecessor to skip the call to
RemoveRedundantDbgInstrs, in effect partially reverting D71480 due to
some compile-time issues spotted in LoopUnroll and SimplifyCFG.
The call to RemoveRedundantDbgInstrs appears to have changed the
worst-case behavior of the merging utility. Loosely speaking, it seems
to have gone from O(#phis) to O(#insts).
It might not be possible to mitigate this by scanning a block to
determine whether there are any debug intrinsics to remove, since such a
scan costs O(#insts).
So: skip the call to RemoveRedundantDbgInstrs. There's surprisingly
little fallout from this, and most of it can be addressed by doing
RemoveRedundantDbgInstrs later. The exception is (the block-local
version of) SimplifyCFG, where it might just be too expensive to call
RemoveRedundantDbgInstrs.
Differential Revision: https://reviews.llvm.org/D88928
CallInst::updateProfWeight() creates branch_weights with i64 instead of i32.
To be more consistent everywhere and remove lots of casts from uint64_t
to uint32_t, use i64 for branch_weights.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D88609
Prepend the module name hash with a fixed string ".__uniq." which helps tools
that consume sampled profiles and attribute it to functions to understand
that this symbol belongs to a unique internal linkage type symbol.
Symbols with suffixes can result from various optimizations in the compiler.
Function Multiversioning, function splitting, parameter constant propogation,
unique internal linkage names.
External tools like sampled profile aggregators combine profiles from multiple
runs of a binary. They use various heuristics with symbols that have suffixes
to try and attribute the profile to the right function instance. For instance
multi-versioned symbols like foo.avx, foo.sse4.2, etc even though different
should be attributed to the same source function if a single function is
versioned, using attribute target_clones (supported in GCC but yet to land in
LLVM). Similarly, functions that are split (split part having a .cold suffix)
could have profiles for both the original and split symbols but would be
aggregated and attributed to the original function that was split.
Unique internal linkage functions however have different source instances and
the aggregator must not put them together but attribute it to the appropriate
function instance. To be sure that we are dealing with a symbol of a unique
internal linkage function, we would like to prepend the hash with a known
string ".__uniq." which these tools can check to understand the suffix type.
Differential Revision: https://reviews.llvm.org/D89617
The exit blocks of the versioned and non-versioned loops are not dedicated and thus the two loops are not in simplify form.
Insert dummy exit blocks after loop versioning with `formDedicatedExits()` to preserve the simplify form for subsequence passes.
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D89569
This change introduces a GC parseable lowering for element atomic
memcpy/memmove intrinsics. This way runtime can provide an
implementation which can take a safepoint during copy operation.
See "GC-parseable element atomic memcpy/memmove" thread on llvm-dev
for the background and details:
https://groups.google.com/g/llvm-dev/c/NnENHzmX-b8/m/3PyN8Y2pCAAJ
Differential Revision: https://reviews.llvm.org/D88861
It's currently ambiguous in IR whether the source language explicitly
did not want a stack a stack protector (in C, via function attribute
no_stack_protector) or doesn't care for any given function.
It's common for code that manipulates the stack via inline assembly or
that has to set up its own stack canary (such as the Linux kernel) would
like to avoid stack protectors in certain functions. In this case, we've
been bitten by numerous bugs where a callee with a stack protector is
inlined into an __attribute__((__no_stack_protector__)) caller, which
generally breaks the caller's assumptions about not having a stack
protector. LTO exacerbates the issue.
While developers can avoid this by putting all no_stack_protector
functions in one translation unit together and compiling those with
-fno-stack-protector, it's generally not very ergonomic or as
ergonomic as a function attribute, and still doesn't work for LTO. See also:
https://lore.kernel.org/linux-pm/20200915172658.1432732-1-rkir@google.com/https://lore.kernel.org/lkml/20200918201436.2932360-30-samitolvanen@google.com/T/#u
Typically, when inlining a callee into a caller, the caller will be
upgraded in its level of stack protection (see adjustCallerSSPLevel()).
By adding an explicit attribute in the IR when the function attribute is
used in the source language, we can now identify such cases and prevent
inlining. Block inlining when the callee and caller differ in the case that one
contains `nossp` when the other has `ssp`, `sspstrong`, or `sspreq`.
Fixes pr/47479.
Reviewed By: void
Differential Revision: https://reviews.llvm.org/D87956
This patch copies @vsk's fix to instcombine from D85555 over to mem2reg. The
motivation and rationale are exactly the same: When mem2reg removes an alloca,
it erases the dbg.{addr,declare} instructions which refer to the alloca. It
would be better to instead remove all debug intrinsics which describe the
contents of the dead alloca, namely all dbg.value(<dead alloca>, ...,
DW_OP_deref)'s.
As far as I can tell, prior to D80264 these `dbg.value+deref`s would have been
silently dropped instead of being made `undef`, so we're just returning to
previous behaviour with these patches.
Testing:
`llvm-lit llvm/test` and `ninja check-clang` gave no unexpected failures. Added
3 tests, each of which covers a dbg.value deletion path in mem2reg:
mem2reg-promote-alloca-1.ll
mem2reg-promote-alloca-2.ll
mem2reg-promote-alloca-3.ll
The first is based on the dexter test inlining.c from D89543. This patch also
improves the debugging experience for loop.c from D89543, which suffers
similarly after arg promotion instead of inlining.
Use isKnownXY comparators when one of the operands can be with
scalable vectors or getFixedSize() for all the other cases.
This patch also does bug fixes for getPrimitiveSizeInBits by using
getFixedSize() near the places with the TypeSize comparison.
Differential Revision: https://reviews.llvm.org/D89703
This reverts commit 26ee8aff2b.
It's necessary to insert bitcast the pointer operand of a lifetime
marker if it has an opaque pointer type.
rdar://70560161
This adds the LLVM IR attribute `mustprogress` as defined in LangRef through D86233. This attribute will be applied to functions with in languages like C++ where forward progress is guaranteed. Functions without this attribute are not required to make progress.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D85393
The main tricky thing here is forward-declaring the enum:
we have to specify it's underlying data type.
In particular, this avoids the danger of switching over the SCEVTypes,
but actually switching over an integer, and not being notified
when some case is not handled.
I have updated most of such switches to be exaustive and not have
a default case, where it's pretty obvious to be the intent,
however not all of them.
If we switch over an enum, compiler can easily issue a diagnostic
if some case is not handled. However with an if cascade that isn't so.
Experimental evidence suggests new behavior to be superior.
All existing SCEV cast types operate on integers.
D89456 will add SCEVPtrToIntExpr cast expression type.
I believe this is best for consistency.
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D89455
This is an initial cleanup of the way LoopVersioning interacts with LAA.
Currently LoopVersioning has 2 ways of initializing things:
1. Passing LAI and passing UseLAIChecks = true
2. Passing UseLAIChecks = false, followed by calling setSCEVChecks and
setAliasChecks.
Both ways of initializing lead to the same result and the duplication
seems more complicated than necessary.
This patch removes the UseLAIChecks flag from the constructor and the
setSCEVChecks & setAliasChecks helpers and move initialization
exclusively to the constructor.
This simplifies things, by providing a single way to initialize
LoopVersioning and reducing duplication.
Reviewed By: Meinersbur, lebedev.ri
Differential Revision: https://reviews.llvm.org/D84406
While we haven't encountered an earth-shattering problem with this yet,
by now it is pretty evident that trying to model the ptr->int cast
implicitly leads to having to update every single place that assumed
no such cast could be needed. That is of course the wrong approach.
Let's back this out, and re-attempt with some another approach,
possibly one originally suggested by Eli Friedman in
https://bugs.llvm.org/show_bug.cgi?id=46786#c20
which should hopefully spare us this pain and more.
This reverts commits 1fb6104293,
7324616660,
aaafe350bb,
e92a8e0c74.
I've kept&improved the tests though.
This relands commit 1c021c64ca which was
reverted in commit 17cec6a11a because
an assertion was being triggered, since `BuildConstantFromSCEV()`
wasn't updated to handle the case where the constant we want to truncate
is actually a pointer. I was unsuccessful in coming up with a test case
where we'd end there with constant zext/sext of a pointer,
so i didn't handle those cases there until there is a test case.
Original commit message:
While we indeed can't treat them as no-ops, i believe we can/should
do better than just modelling them as `unknown`. `inttoptr` story
is complicated, but for `ptrtoint`, it seems straight-forward
to model it just as a zext-or-trunc of unknown.
This may be important now that we track towards
making inttoptr/ptrtoint casts not no-op,
and towards preventing folding them into loads/etc
(see D88979/D88789/D88788)
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D88806
> While we indeed can't treat them as no-ops, i believe we can/should
> do better than just modelling them as `unknown`. `inttoptr` story
> is complicated, but for `ptrtoint`, it seems straight-forward
> to model it just as a zext-or-trunc of unknown.
>
> This may be important now that we track towards
> making inttoptr/ptrtoint casts not no-op,
> and towards preventing folding them into loads/etc
> (see D88979/D88789/D88788)
>
> Reviewed By: mkazantsev
>
> Differential Revision: https://reviews.llvm.org/D88806
It caused the following assert during Chromium builds:
llvm/lib/IR/Constants.cpp:1868:
static llvm::Constant *llvm::ConstantExpr::getTrunc(llvm::Constant *, llvm::Type *, bool):
Assertion `C->getType()->isIntOrIntVectorTy() && "Trunc operand must be integer"' failed.
See code review for a link to a reproducer.
This reverts commit 1c021c64ca.
60b852092c introduced SCEV verification to
deleteDeadLoop, but it appears this check is currently a bit over-eager
and some users of deleteDeadLoop appear to only patch up SE after
calling it (e.g. PR47753).
Remove the extra check for now. We can consider adding it back after we
tracked down the source of the inconsistency for PR47753.
While we indeed can't treat them as no-ops, i believe we can/should
do better than just modelling them as `unknown`. `inttoptr` story
is complicated, but for `ptrtoint`, it seems straight-forward
to model it just as a zext-or-trunc of unknown.
This may be important now that we track towards
making inttoptr/ptrtoint casts not no-op,
and towards preventing folding them into loads/etc
(see D88979/D88789/D88788)
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D88806
In the NPM, a pass cannot depend on another non-analysis pass. So pin
the test that tests that -lowerswitch is run automatically to legacy PM.
Reviewed By: sameerds
Differential Revision: https://reviews.llvm.org/D89051
Use cast<> as we immediately dereference the pointer afterwards - cast<> will assert if we fail.
Prevents clang static analyzer warning that we could deference a null pointer.
Add basic vector handling to recognizeBSwapOrBitReverseIdiom/collectBitParts - this works at the element level, all vector element operations must match (splat constants etc.) and there is no cross-element support (insert/extract/shuffle etc.).
If we're bswap'ing some bytes and zero'ing the remainder we can perform this as a bswap+mask which helps us match 'partial' bswaps as a first step towards folding into a more complex bswap pattern.
Reapplied with early-out if recognizeBSwapOrBitReverseIdiom collects a source wider than the result type.
Differential Revision: https://reviews.llvm.org/D88578
If we're bswap'ing some bytes and zero'ing the remainder we can perform this as a bswap+mask which helps us match 'partial' bswaps as a first step towards folding into a more complex bswap pattern.
Differential Revision: https://reviews.llvm.org/D88578
If we try to coerce a vector of non-integral pointers to a narrower type (either narrower vector or single pointer), we use inttoptr and violate the semantics of non-integral pointers. In theory, we can handle many of these cases, we just need to use a different code idiom to convert without going through inttoptr and back.
This shows up as wrong code bugs, and in some cases, crashes due to failed asserts. Modeled after a change which has lived downstream for a couple years, though completely rewritten to be more idiomatic.
Make sure we're using getScalarSizeInBits instead of cast<IntegerType> to get Type bit widths.
This is preliminary cleanup before we can start adding vector support to the bswap/bitreverse (element level) matching.
There doesn't seem to be any good reason for having a separate path for when we bswap/bitreverse at a smaller size than the destination size - so merge these to make the instruction generation a lot clearer.
Fix a number of WShadow warnings (I was used as the instruction and index......) and fix cases to match style.
Also, replaced the Bit APInt mask check in AND instructions with a direct APInt[] bit check.
PR39793 demonstrated an issue where we fail to recognize 'partial' bswap patterns of the lower bytes of an integer source.
In fact, most of this is already in place collectBitParts suitably tags zero bits, so we just need to correctly handle this case by finding the zero'd upper bits and reducing the bswap pattern just to the active demanded bits.
Differential Revision: https://reviews.llvm.org/D88316
This patch adds noundef to the returned pointers of allocators (malloc, calloc, ...)
and the pointer argument of free.
The returned pointer of allocators cannot be poison or (partially) undef.
Since the pointer that is given to free should precisely have zero offset,
it cannot be poison or (partially) undef too.
For the size arguments of allocators, noundef wasn't attached simply because
I wasn't sure whether attaching it is okay or not.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D87984
When removing an overflow intrinsic the Changed status in SimplifyIndvar
was not set, leading to the IndVarSimplify pass returning an incorrect
status.
This was caught using the check introduced by D80916.
As pointed out in the code review, a similar bug may exist for
eliminateTrunc().
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D85971
After D71539, we need to forget the loop before setting the incoming
values of phi nodes in exit blocks, because we are looking through those
phi nodes now and the SCEV expression could depend on the loop phi. If
we update the phi nodes before forgetting the loop, we miss those users
during invalidation.
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D88167
Require CxtI in getConstant() and getConstantRange() APIs.
Accordingly drop the BB parameter, as it is implied by
CxtI->getParent().
This makes sure we don't forget to pass the context instruction,
and makes the API contract clearer (also clean up the comments to
that effect -- the value holds at the context instruction, not
the end of the block).
Pulled from D87452, this is a fixed version of the collectBitParts fshl/fshr handling which as @nikic noticed wasn't checking for different providers or had correct bit ordering (which was hid by only testing shift amounts of bitwidth/2).
Differential Revision: https://reviews.llvm.org/D88292
This seems to fit the CGSCC updates model better than calling
addNewFunctionInto{Ref,}SCC() on newly created/outlined functions.
Now addNewFunctionInto{Ref,}SCC() are no longer necessary.
However, this doesn't work on newly outlined functions that aren't
referenced by the original function. e.g. if a() was outlined into b()
and c(), but c() is only referenced by b() and not by a(), this will
trigger an assert.
This also fixes an issue I was seeing with newly created functions not
having passes run on them.
Ran check-llvm with expensive checks.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D87798
A conversion from `pow` to `sqrt` shall not call an `errno`-setting
`sqrt` with -//infinity//: the `sqrt` will set `EDOM` where the `pow`
call need not.
This patch avoids the erroneous (pun not intended) transformation by
applying the restrictions discussed in the thread for
https://lists.llvm.org/pipermail/llvm-dev/2020-September/145051.html.
The existing tests are updated (depending on emphasis in the checks for
library calls, avoidance of overlap, and overall coverage):
- to add `ninf`, retaining the intended library call,
- to use the intrinsic, retaining the use of `select`, or
- to expect the replacement to not occur.
The following is tested:
- The pow intrinsic folds to a `select` instruction to
handle -//infinity//.
- The pow library call folds, with `ninf`, to `sqrt` without the
`select` instruction associated with handling -//infinity//.
- The pow library call does not fold to `sqrt` without `ninf`.
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D87877
The current code for handling pow(x, y) where y is an integer plus 0.5
is not explicitly guarded against attempting to transform the case where
abs(y) is exactly 0.5.
The latter case is meant to be handled by `replacePowWithSqrt`. Indeed,
if the pow(x, integer+0.5) case proceeds past a certain point, it will
hit an assertion by attempting to form pow(x, 0) using `getPow`.
This patch adds an explicit check to prevent attempting the
pow(x, integer+0.5) transformation on pow(x, +/-0.5) as suggested during
the review of D87877. This has the effect of retaining the shrinking of
`pow` to `powf` when the `sqrt` libcall cannot be formed.
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D88066
I want to export this function, and the current API was a bit
weird: It took an additional Alignment argument that didn't really
have anything to do with what the function does. Drop it, and
perform a max at the callsite.
Also rename it to tryEnforceAlignment().
Currently SCEVExpander creates inttoptr for non-integral pointers if the
base is a null constant for example. This results in invalid IR.
This patch changes InsertNoopCastOfTo to emit a GEP & bitcast to convert
to a non-integral pointer. First, a GEP of i8* null is generated and the
integral value is used as index. The GEP is then bitcasted to the target
type.
This was exposed by D71539.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D87827
~~D65060 uncovered that trying to use BFI in loop passes can lead to non-deterministic behavior when blocks are re-used while retaining old BFI data.~~
~~To make sure BFI is preserved through loop passes a Value Handle (VH) callback is registered on blocks themselves. When a block is freed it now also wipes out the accompanying BFI entry such that stale BFI data can no longer persist resolving the determinism issue. ~~
~~An optimistic approach would be to incrementally update BFI information throughout the loop passes rather than only invalidating them on removed blocks. The issues with that are:~~
~~1. It is not clear how BFI information should be incrementally updated: If a block is duplicated does its BFI information come with? How about if it's split/modified/moved around? ~~
~~2. Assuming we can address these problems the implementation here will be a massive undertaking. ~~
~~There's a known need of BFI in LICM analysis which requires correct but not incrementally updated BFI data. A follow-up change can register BFI in all loop passes so this preserved but potentially lossy data is available to any loop pass that wants it.~~
See: D75341 for an identical implementation of preserving BFI via VH callbacks. The previous statements do still apply but this change no longer has to be in this diff because it's already upstream 😄 .
This diff also moves BFI to be a part of LoopStandardAnalysisResults since the previous method using getCachedResults now (correctly!) statically asserts (D72893) that this data isn't static through the loop passes.
Testing
Ninja check
Reviewed By: asbirlea, nikic
Differential Revision: https://reviews.llvm.org/D86156
Call instructions with musttail tag must be optimized as a tailcall, otherwise could lead to incorrect program behavior.
When TSAN is instrumenting functions, it broke the contract by adding a call to the tsan exit function inbetween the musttail call and return instruction, and also inserted exception handling code.
This happend throguh EscapeEnumerator, which adds exception handling code and returns ret instructions as the place to insert instrumentation calls.
This becomes especially problematic for coroutines, because coroutines rely on tail calls to do symmetric transfers properly.
To fix this, this patch moves the location to insert instrumentation calls prior to the musttail call for ret instructions that are following musttail calls, and also does not handle exception for musttail calls.
Differential Revision: https://reviews.llvm.org/D87620
The FailureReason input parameter maybe null, we check this in all other cases in the method but this one was missed somehow.
Fixes clang-tidy warning.
When inlining functions containing allocas of scalable vectors we
cannot specify the size in the lifetime markers, since we don't
know this at compile time.
Added new test here:
test/Transforms/Inline/AArch64/sve-alloca-merge.ll
Differential Revision: https://reviews.llvm.org/D87139
As code size is the only thing we care about at minsize, query the
cost of materialising immediates when calculating the cost of a SCEV
expansion. We also modify the CostKind to TCK_CodeSize for minsize,
instead of RecipThroughput.
Differential Revision: https://reviews.llvm.org/D76434
If a function had at most one return block, the pass would return false
regardless if an unified unreachable block was created.
This patch fixes that by refactoring runOnFunction into two separate
helper functions for handling the unreachable blocks respectively the
return blocks, as suggested by @bjope in a review comment.
This was caught using the check introduced by D80916.
Reviewed By: serge-sans-paille
Differential Revision: https://reviews.llvm.org/D85818
This patch follows D85345 and adds more noundef attributes to return values/arguments of library functions
that are mostly about accessing the file system or processes.
A few functions like `chmod` or `times` use typedef `mode_t` and `clock_t`.
They are neither struct nor union, so they cannot contain undef even if they're lowered to iN in IR. So, it is fine to add noundef to them.
- clock_t's actual type is size_t (C17, 7.27.1.3), so it isn't struct or union.
- For mode_t, either int or long is used in practice because programmers use bit manipulation. So, I think it is okay that it's never aggregate in practice.
After this patch, the remaining library functions are those that eagerly participate in optimizations: they can be removed, reordered, or
introduced by a transformation from primitive IR operations.
For them, a few testings is needed, since it may not be valid to add noundef anymore even if C standard says it's okay.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D85894
The get{Return,Unwind,Unreachable}Block functions in
UnifyFunctionExitNodes have not been used for many years,
so just remove them.
Reviewed By: bjope
Differential Revision: https://reviews.llvm.org/D87078
To enable the cost of constants, the helper function has been
reorganised:
- A struct has been introduced to hold SCEV operand information so
that we know the user of the operand, as well as the operand index.
The Worklist now uses instead instead of a bare SCEV.
- The costing of each SCEV, and collection of its operands, is now
performed in a helper function.
Differential Revision: https://reviews.llvm.org/D86050
Modify FoldBranchToCommonDest to consider the cost of inserting
instructions when attempting to combine predicates to fold blocks.
The threshold can be controlled via a new option:
-simplifycfg-branch-fold-threshold which defaults to '2' to allow
the insertion of a not and another logical operator.
Differential Revision: https://reviews.llvm.org/D86526
When a switch case is folded into default's case, that's an IR change that
should be reported, update ConstantFoldTerminator accordingly.
Differential Revision: https://reviews.llvm.org/D87142
EarlyCSE has a mode to verify the invariant that hash equality equals
key equality, but EliminateDuplicatePHINodes() doesn't.
I've verified that this would have caught the stage2-stage3 mismatches
5ec2b757cc revert has fixed,
that were introduced last time in 3e69871ab5.
This patch changes ElementCount so that the Min and Scalable
members are now private and can only be accessed via the get
functions getKnownMinValue() and isScalable(). In addition I've
added some other member functions for more commonly used operations.
Hopefully this makes the class more useful and will reduce the
need for calling getKnownMinValue().
Differential Revision: https://reviews.llvm.org/D86065
strspn, strncmp, strcspn, strcasecmp, strncasecmp, memcmp, memchr,
memrchr, memcpy, memmove, memcpy, mempcpy, strchr, strrchr, bcmp
should all only access memory through their arguments.
I broke out strcoll, strcasecmp, strncasecmp because the result
depends on the locale, which might get accessed through memory.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86724
Currently we bail out early for strlen calls with a GEP operand, if none
of the GEP specific optimizations fire. But there could be later
optimizations that still apply, which we currently miss out on.
An example is that we do not apply the following optimization
strlen(x) == 0 --> *x == 0
Unless I am missing something, there seems to be no reason for bailing
out early there.
Fixes PR47149.
Reviewed By: lebedev.ri, xbolva00
Differential Revision: https://reviews.llvm.org/D85886
When trying to enable -debug-info-kind=constructor there was an assert
that occurs during debug info cloning ("mismatched subprogram between
llvm.dbg.value variable and !dbg attachment").
It appears that during llvm::CloneFunctionInto, a DISubprogram could be
duplicated when MapMetadata is called, and then added to the MD map again
when DIFinder gets a list of subprograms. This results in two different
versions of the DISubprogram.
This patch switches the order so that the DIFinder subprograms are
added before MapMetadata is called.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46784
Differential Revision: https://reviews.llvm.org/D86185
Recommit the patch after fixing an issue reported caused by the fact
that re-used values are also added to InsertedValues.
Additional tests have been added in 88818491b9
This reverts the revert commit 38884641f2.
Before we speculatively execute a basic block, query the cost of
inserting the necessary select instructions against the phi folding
threshold. For non-trivial insertions, a more accurate decision can
probably be made during machine if-conversion. With minsize we query
the CodeSize cost, otherwise we use SizeAndLatency.
Differential Revision: https://reviews.llvm.org/D82438
This reverts commit 6dbf0cfcf7.
That commit caused failed assertions, e.g. like this:
$ cat sprintf-strcpy.c
char *ptr; void func(void) { ptr += sprintf(ptr, "%s", ""); }
$ clang -c sprintf-strcpy.c -O2 -target x86_64-linux-gnu
clang: ../lib/IR/Value.cpp:473: void llvm::Value::doRAUW(llvm::Value*,
llvm::Value::ReplaceMetadataUses): Assertion `New->getType() ==
getType() && "replaceAllUses of value with new value of different
type!"' failed.
Transformation creates big strings for big C values, so bail out for C > 128.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D86004
When removing instructions from unreachable blocks, and only debug info
intrinsics were removed, InstCombine could incorrectly return a false
Modified status.
This is fixed by making removeAllNonTerminatorAndEHPadInstructions()
also return how many debug info intrinsics that were removed, and take
that into account.
This was caught using the check introduced by D80916.
Reviewed By: majnemer
Differential Revision: https://reviews.llvm.org/D85839
SCEVExpander already tracks which instructions have been inserted n
InsertedValues/InsertedPostIncValues. This patch adds an additional
vector to collect the instructions in insertion order. This can then be
used to remove exactly the instructions inserted by the expander.
This replaces ExpandedValuesCleaner, which in some cases might remove
values not inserted by the expander (e.g. if a value was dead before
insertion and is then used during expansion).
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D84327
This patch adds noundef to return value and arguments of standard I/O functions.
With this patch, passing undef or poison to the functions becomes undefined
behavior in LLVM IR. Since undef/poison is lowered from operations having UB in C/C++,
passing undef to them was already UB in source.
With this patch, the functions cannot return undef or poison anymore as well.
According to C17 standard, ungetc/ungetwc/fgetpos/ftell can generate unspecified
value; 3.19.3 says unspecified value is a valid value of the relevant type,
and using unspecified value is unspecified behavior, which is not UB, so it
cannot be undef (using undef is UB when e.g. it is used at branch condition).
— The value of the file position indicator after a successful call to the ungetc function for a text stream, or the ungetwc function for any stream, until all pushed-back characters are read or discarded (7.21.7.10, 7.29.3.10).
— The details of the value stored by the fgetpos function (7.21.9.1).
— The details of the value returned by the ftell function for a text stream (7.21.9.4).
In the long run, most of the functions listed in BuildLibCalls should have noundefs; to remove redundant diffs which will anyway disappear in the future, I added noundef to a few more non-I/O functions as well.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D85345
Currently the SCEVExpander tries to re-use existing casts, even if they
are not exactly at the insertion point it was asked to create the cast.
To do so in some case, it creates a new cast at the insertion point and
updates all users to use the new cast.
This behavior is problematic, because it changes the IR outside of the
instructions created during the expansion. Therefore we cannot
completely undo all changes made during expansion.
This re-use should be only an extra optimization, so only using the new
cast in the expanded instructions should not be a correctness issue.
There are many cases equivalent instructions are created during
expansion.
This patch also adjusts findInsertPointAfter to skip instructions
inserted during expansion. This enables re-using existing casts without
the renaming any uses, by picking a better insertion point.
Reviewed By: efriedma, lebedev.ri
Differential Revision: https://reviews.llvm.org/D84399
SimplifyCFG has two main folds for resumes - one when resume is directly
using the landingpad, and the other one where resume is using a PHI node.
While for the first case, we were already correctly ignoring all the
PHI nodes, and both the debug info intrinsics and lifetime intrinsics,
in the PHI-based-one, we weren't ignoring PHI's in the resume block,
and weren't ignoring lifetime intrinsics. That is clearly a bug.
On RawSpeed library, this results in +9.34% (+81) more invoke->call folds,
-0.19% (-39) landing pads, -0.24% (-81) invoke instructions
but +51 call instructions and -132 basic blocks.
Though, the run-time performance impact appears to be within the noise.
formLCSSAForInstructions is used by SCEVExpander, which tracks all
inserted instructions including LCSSA phis using asserting value
handles. This means cleanup needs to happen in the caller.
Extend formLCSSAForInstructions to take an optional pointer to a
vector. If this argument is non-nullptr, instead of directly deleting
the phis, add them to the vector, so the caller can process them.
This should address various PPC buildbot failures, including
http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/40567
Use IRBuilder instead PHINode::Create. This should not impact the
generated code, but IRBuilder provides a way to register callbacks for
inserted instructions, which is convenient for some users.
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D85037
querying getSCEV() for incomplete phis leads to wrong cache value in `ExprToIVMap`,
because incomplete phis may be simplified to same value before get SCEV expression.
Reviewed By: lebedev.ri, mkazantsev
Differential Revision: https://reviews.llvm.org/D77560
Summary: This patch separates the Loop Peeling Utilities from Loop Unrolling.
The reason for this change is that Loop Peeling is no longer only being used by
loop unrolling; Patch D82927 introduces loop peeling with fusion, such that
loops can be modified to have to same trip count, making them legal to be
peeled.
Reviewed By: Meinersbur
Differential Revision: https://reviews.llvm.org/D83056
This reverts the revert commit dc28675768.
It includes a fix for Polly, which uses SCEVExpander on IR that is not
in LCSSA form. Set PreserveLCSSA = false in that case, to ensure we do
not introduce LCSSA phis where there were none before.
This reverts commit 99166fd4fb, because it
breaks the polly builders.
polly/test/Isl/CodeGen/invariant_load_escaping_second_scop.ll fails
because a apparently unnecessary LCSSA phi node is introduced.
Make the bots green again, while I take a closer look.
This patch teaches SCEVExpander to directly preserve LCSSA.
As it is currently, SCEV does not look through PHI nodes in loops,
as it might break LCSSA form. Once SCEVExpander can preserve
LCSSA form, it should be safe for SCEV to look through PHIs.
To preserve LCSSA form, this patch uses formLCSSAForInstructions
on operands of newly created instructions, if the definition is inside
a different loop than the new instruction.
The final value we return from expandCodeFor may also need LCSSA
phis, depending on the insert point. As no user for it exists there yet,
create a temporary instruction at the insert point, which can be passed
to formLCSSAForInstructions. This temporary instruction is removed
after LCSSA construction.
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D71538
Currently, getCastInstrCost has limited information about the cast it's
rating, often just the opcode and types. Sometimes there is a context
instruction as well, but it isn't trustworthy: for instance, when the
vectorizer is rating a plan, it calls getCastInstrCost with the old
instructions when, in fact, it's trying to evaluate the cost of the
instruction post-vectorization. Thus, the current system can get the
cost of certain casts incorrect as the correct cost can vary greatly
based on the context in which it's used.
For example, if the vectorizer queries getCastInstrCost to evaluate the
cost of a sext(load) with tail predication enabled, getCastInstrCost
will think it's free most of the time, but it's not always free. On ARM
MVE, a VLD2 group cannot be extended like a normal VLDR can. Similar
situations can come up with how masked loads can be extended when being
split.
To fix that, this path adds a new parameter to getCastInstrCost to give
it a hint about the context of the cast. It adds a CastContextHint enum
which contains the type of the load/store being created by the
vectorizer - one for each of the types it can produce.
Original patch by Pierre van Houtryve
Differential Revision: https://reviews.llvm.org/D79162
We can happily turn function definitions into declarations,
thus obscuring their argument from being elided by this pass.
I don't believe there is a good reason to just ignore declarations.
likely even proper llvm intrinsics ones,
at worst the input becomes uninteresting.
The other question here is that all these transforms are all-or-nothing.
In some cases, should we be treating each use separately?
The main blocker here seemed to be that llvm::CloneFunctionInto()
does `&OldFunc->front()`, which inserts a nullptr into a densemap,
which is not happy about it and asserts.
This is the first of two patches to address PR46753. We basically allow
mem2reg to promote allocas that are used in doppable instructions, for
now that means `llvm.assume`. The uses of the alloca (or a bitcast or
zero offset GEP from there) are replaced by `undef` in the droppable
instructions.
Reviewed By: Tyker
Differential Revision: https://reviews.llvm.org/D83976
SROA knows that it can look through addrspacecast but
PromoteMemoryToRegister did not handle them. This caused an assertion
error for the test case, exposed while running
`Transforms/PhaseOrdering/inlining-alignment-assumptions.ll` with D83978
applied.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D84085
PassManager.h is one of the top headers in the ClangBuildAnalyzer frontend worst offenders list.
This exposes a large number of implicit dependencies on various forward declarations/includes in other headers that need addressing.
As long as RenamedOp is not guaranteed to be accurate, we cannot
assert here and should just return false. This was already done
for the other conditions in this function.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46814.
Currently there are plenty of instructions that SCEVExpander creates but
does not track as created. IRBuilder allows specifying a callback
whenever an instruction is inserted. Use this to call
rememberInstruction automatically for each created instruction.
There are still a few rememberInstruction calls remaining, because in
some cases Inst::Create functions are used to construct instructions.
Suggested by @lebedev.ri in D75980.
Reviewers: mkazantsev, reames, sanjoy.google, lebedev.ri
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D84326
The revert was a misfire.
Remove the temporary flag PGSOIRPassOrTestOnly and the guard code which was used
for the staged rollout. This is a cleanup (NFC) as it's now false by default.
Differential Revision: https://reviews.llvm.org/D84057
This reverts commit e64afefdf8. It caused
a PGO bootstrapped clang to crash on many source files.
`__llvm_profile_instrument_range` seems to trigger a null pointer dereference.
Call stack:
__llvm_profile_instrument_range
llvm::APInt::udiv(llvm::APInt const&) const
getRangeForAffineARHelper
We do not thread blocks with convergent calls, but this check was missing
when we decide to insert PR Phis into it (which we only do for threading).
Differential Revision: https://reviews.llvm.org/D83936
Reviewed By: nikic
Remove the temporary flag PGSOIRPassOrTestOnly and the guard code which was used
for the staged rollout. This is a cleanup (NFC) as it's now false by default.
Differential Revision: https://reviews.llvm.org/D84057
This patch adds a TileInfo abstraction and utilities to
create a 3-level loop nest for tiling.
Reviewers: anemet
Reviewed By: anemet
Differential Revision: https://reviews.llvm.org/D77550
This allows tracking the in-memory type of a pointer argument to a
function for ABI purposes. This is essentially a stripped down version
of byval to remove some of the stack-copy implications in its
definition.
This includes the base IR changes, and some tests for places where it
should be treated similarly to byval. Codegen support will be in a
future patch.
My original attempt at solving some of these problems was to repurpose
byval with a different address space from the stack. However, it is
technically permitted for the callee to introduce a write to the
argument, although nothing does this in reality. There is also talk of
removing and replacing the byval attribute, so a new attribute would
need to take its place anyway.
This is intended avoid some optimization issues with the current
handling of aggregate arguments, as well as fixes inflexibilty in how
frontends can specify the kernel ABI. The most honest representation
of the amdgpu_kernel convention is to expose all kernel arguments as
loads from constant memory. Today, these are raw, SSA Argument values
and codegen is responsible for turning these into loads.
Background:
There currently isn't a satisfactory way to represent how arguments
for the amdgpu_kernel calling convention are passed. In reality,
arguments are passed in a single, flat, constant memory buffer
implicitly passed to the function. It is also illegal to call this
function in the IR, and this is only ever invoked by a driver of some
kind.
It does not make sense to have a stack passed parameter in this
context as is implied by byval. It is never valid to write to the
kernel arguments, as this would corrupt the inputs seen by other
dispatches of the kernel. These argumets are also not in the same
address space as the stack, so a copy is needed to an alloca. From a
source C-like language, the kernel parameters are invisible.
Semantically, a copy is always required from the constant argument
memory to a mutable variable.
The current clang calling convention lowering emits raw values,
including aggregates into the function argument list, since using
byval would not make sense. This has some unfortunate consequences for
the optimizer. In the aggregate case, we end up with an aggregate
store to alloca, which both SROA and instcombine turn into a store of
each aggregate field. The optimizer never pieces this back together to
see that this is really just a copy from constant memory, so we end up
stuck with expensive stack usage.
This also means the backend dictates the alignment of arguments, and
arbitrarily picks the LLVM IR ABI type alignment. By allowing an
explicit alignment, frontends can make better decisions. For example,
there's real no advantage to an aligment higher than 4, so a frontend
could choose to compact the argument layout. Similarly, there is a
high penalty to using an alignment lower than 4, so a frontend could
opt into more padding for small arguments.
Another design consideration is when it is appropriate to expose the
fact that these arguments are all really passed in adjacent
memory. Currently we have a late IR optimization pass in codegen to
rewrite the kernel argument values into explicit loads to enable
vectorization. In most programs, unrelated argument loads can be
merged together. However, exposing this property directly from the
frontend has some disadvantages. We still need a way to track the
original argument sizes and alignments to report to the driver. I find
using some side-channel, metadata mechanism to track this
unappealing. If the kernel arguments were exposed as a single buffer
to begin with, alias analysis would be unaware that the padding bits
betewen arguments are meaningless. Another family of problems is there
are still some gaps in replacing all of the available parameter
attributes with metadata equivalents once lowered to loads.
The immediate plan is to start using this new attribute to handle all
aggregate argumets for kernels. Long term, it makes sense to migrate
all kernel arguments, including scalars, to be passed indirectly in
the same manner.
Additional context is in D79744.
Common code sinking is already guarded with a (with default-off!) flag,
so add a flag for hoisting, too.
D84108 will hopefully make hoisting off-by-default too.
Both users of predicteinfo (NewGVN and SCCP) are interested in
getting a cmp constraint on the predicated value. They currently
implement separate logic for this. This patch adds a common method
for this in PredicateBase.
This enables a missing bit of PredicateInfo handling in SCCP: Now
the predicate on the condition itself is also used. For switches
it means we know that the switched-on value is the same as the case
value. For assumes/branches we know that the condition is true or
false.
Differential Revision: https://reviews.llvm.org/D83640
Summary:
This patch resolves an issue where the metadata of a loop is not added to the
new loop latch, and not removed from the old loop latch. This issue occurs in
the SplitBlockPredecessors function, which adds a new block in a loop, and
in the case that the block passed into this function is the header of the loop,
the loop can be modified such that the latch of the loop is replaced.
This patch applies to the Loop Simplify pass since it ensures that each loop
has exit blocks which only have predecessors that are inside of the loop. In
the case that this is not true, the pass will create a new exit block for the
loop. This guarantees that the loop preheader/header will dominate the exit blocks.
Author: sidbav (Sidharth Baveja)
Reviewers: asbirlea (Alina Sbirlea), chandlerc (Chandler Carruth), Whitney (Whitney Tsang), bmahjour (Bardia Mahjour)
Reviewed By: asbirlea (Alina Sbirlea)
Subscribers: hiraditya (Aditya Kumar), llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D83869
SimplifyCFG was incorrectly reporting to the pass manager that it had not made
changes after folding away a PHI. This is detected in the EXPENSIVE_CHECKS
build when the function's hash changes.
Differential Revision: https://reviews.llvm.org/D83985
When the byref attribute is added, there will need to be two similar
functions for the existing cases which have an associate value copy,
and byref which does not. Most, but not all of the existing uses will
use the existing version.
The associated size function added by D82679 also needs to
contextually differ, and will help eliminate a few places still
relying on pointee element types.
Unrolling a loop with compile-time unknown trip count results in a remainder loop. The remainder loop executes the remaining iterations of the original loop when the original trip count is not a multiple of the unroll factor. For better profile counts maintenance throughout the optimization pipeline, I'm assigning an artificial weight to the latch branch of the remainder loop.
A remainder loop runs up to as many times as the unroll factor subtracted by 1. Therefore I'm assigning the maximum possible trip count as the back edge weight. This should be more accurate than the default non-profile weight, which assumes the back edge runs much more frequently than the exit edge.
Differential Revision: https://reviews.llvm.org/D83187
CodeGenPrepare keeps fairly close track of various instructions it's
seen, particularly GEPs, in maps and vectors. However, sometimes those
instructions become dead and get removed while it's still executing.
This triggers AssertingVH references to them in an asserts build and
could lead to miscompiles in a release build (I've only seen a later
segfault though).
So this patch adds a callback to
RecursivelyDeleteTriviallyDeadInstructions which can make sure the
instruction about to be deleted is removed from CodeGenPrepare's data
structures.
The actual rotation happens in processLoop, so the second removed
call to verifyMemorySSA was unnecessary.
In fact, processLoop/rotateLoop already verify MemorySSA before
and after transforming each loop. Hence, both calls can be removed.
Pointed out by @lebedev.ri post-commit D51718.
Summary:
Add debug counter and stats counter to assume queries and assume builder
here is the collected stats on a build of check-llvm + check-clang.
"assume-builder.NumAssumeBuilt": 2720879,
"assume-builder.NumAssumesMerged": 761396,
"assume-builder.NumAssumesRemoved": 1576212,
"assume-builder.NumBundlesInAssumes": 6518809,
"assume-queries.NumAssumeQueries": 85566380,
"assume-queries.NumUsefullAssumeQueries": 2727360,
the NumUsefullAssumeQueries stat is actually pessimistic because in a few places queries
ask to keep providing information to try to get better information. and this isn't counted
as a usefull query evem tho it can be usefull
Reviewers: jdoerfert
Reviewed By: jdoerfert
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83506
This fixes warnings raised by Clang's new -Wsuggest-override, in preparation for enabling that warning in the LLVM build. This patch also removes the virtual keyword where redundant, but only in places where doing so improves consistency within a given file. It also removes a couple unnecessary virtual destructor declarations in derived classes where the destructor inherited from the base class is already virtual.
Differential Revision: https://reviews.llvm.org/D83709
Here we teach the ConstantFolding analysis pass that it is not legal to
replace a load of a bitcast constant (having a non-integral addrspace)
with a bitcast of the value of that constant (with a different
non-integral addrspace).
But also teach it that certain bit patterns are always known and
convertable (a fact it already uses elsewhere). This required us to also
fix a globalopt test, since, after this change, LLVM is able to realize
that the test actually is a valid transform (NULL is always a known
bit-pattern) and so it doesn't need to emit the failure remarks for it.
Also simplify some of the negative tests for transforms by avoiding a
type change in their bitcast, and add positive versions of the same
tests, to show that they otherwise should work.
Differential Revision: https://reviews.llvm.org/D59730
This could previously make it more complicated for ConstantFolding
later, leading to a higher likelyhood it would have to reject the
expression, even though zero seems like probably the common case here.
Differential Revision: https://reviews.llvm.org/D59730
Currently, a transformation like pow(2.0, x) -> exp2(x) copies the pow
attribute list verbatim and applies it to exp2. This works out fine
when the attribute list is empty, but when it isn't clang may error due
due to the mismatch.
The source function and destination don't necessarily have anything
to do with one another, attribute-wise. So it makes sense to remove
the attribute lists (this is similar to what IPO does in this
situation).
This was discovered after implementing the `noundef` param attribute.
Differential Revision: https://reviews.llvm.org/D82820
Place the ssa.copy instructions for assumes after the assume,
instead of before it. Both options are valid, but placing them
afterwards prevents assumes from being replaced with assume(true).
This fixes https://bugs.llvm.org/show_bug.cgi?id=37541 in NewGVN
and will avoid a similar issue in SCCP when we handle more
predicate infos.
Differential Revision: https://reviews.llvm.org/D83631
Summary:
- Skip unreachable predecessors during header detection in SCC. Those
unreachable blocks would be generated in the switch lowering pass in
the corner cases or other frontends. Even though they could be removed
through the CFG simplification, we should skip them during header
detection.
Reviewers: sameerds
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83562
Summary:
This patch separates the peeling specific parameters from the UnrollingPreferences,
and creates a new struct called PeelingPreferences. Functions which used the
UnrollingPreferences struct for peeling have been updated to use the PeelingPreferences struct.
Author: sidbav (Sidharth Baveja)
Reviewers: Whitney (Whitney Tsang), Meinersbur (Michael Kruse), skatkov (Serguei Katkov), ashlykov (Arkady Shlykov), bogner (Justin Bogner), hfinkel (Hal Finkel), anhtuyen (Anh Tuyen Tran), nikic (Nikita Popov)
Reviewed By: Meinersbur (Michael Kruse)
Subscribers: fhahn (Florian Hahn), hiraditya (Aditya Kumar), llvm-commits, LLVM
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D80580
Summary: This patch moves OrderedInstructions to CodeMoverUtils as It was
the only place where OrderedInstructions is required.
Authored By: RithikSharma
Reviewer: Whitney, bmahjour, etiotto, fhahn, nikic
Reviewed By: Whitney, nikic
Subscribers: mgorny, hiraditya, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D80643
The block front may be a PHI node, inserting a cast instructions like
BitCast, PtrToInt, IntToPtr among PHIs is not right.
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D80975
OriginalOp of a predicate always refers to the original IR
value that was renamed. So for nested predicates of the same value, it
will always refer to the original IR value.
For the use in SCCP however, we need to find the renamed value that is
currently used in the condition associated with the predicate. This
patch adds a new RenamedOp field to do exactly that.
NewGVN currently relies on the existing behavior to merge instruction
metadata. A test case to check for exactly that has been added in
195fa4bfae.
Reviewers: efriedma, davide, nikic
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D78133
The `noundef` attribute indicates an argument or return value which
may never have an undef value representation.
This patch allows LLVM to parse the attribute.
Differential Revision: https://reviews.llvm.org/D83412
Summary: This patch makes code motion checks optional which are dependent on
specific analysis example, dominator tree, post dominator tree and dependence
info. The aim is to make the adoption of CodeMoverUtils easier for clients that
don't use analysis which were strictly required by CodeMoverUtils. This will
also help in diversifying code motion checks using other analysis example MSSA.
Authored By: RithikSharma
Reviewer: Whitney, bmahjour, etiotto
Reviewed By: Whitney
Subscribers: Prazek, hiraditya, george.burgess.iv, asbirlea, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D82566
Summary:
It is reasonably common to want to clone some call with different bundles.
Let's actually provide an interface to do that.
Reviewers: chandlerc, jdoerfert, dblaikie, nickdesaulniers
Reviewed By: nickdesaulniers
Subscribers: llvm-commits, hiraditya
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83248
Summary:
Avoid exposing details about how children are stored. This will enable
subsequent type-erasure changes.
New methods are introduced to cover common access patterns.
Change-Id: Idb5f4b1b9c84e4cc71ddb39bb52a388682f5674f
Reviewers: arsenm, RKSimon, mehdi_amini, courbet
Subscribers: qcolombet, sdardis, wdng, hiraditya, jrtc27, zzheng, atanasyan, asbirlea, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83083
clang w/ old-pm currently would simply crash
when -mllvm -enable-knowledge-retention=true is specified.
Clearly, these two passes had no Old-PM test coverage,
which would have shown the problem - not requiring AssumptionCacheTracker,
but then trying to always get it.
Also, why try to get domtree only if it's cached,
but at the same time marking it as required?
Summary:
This patch changes call graph analysis to recognize callback call sites
and add an artificial 'reference' call record from the broker function
caller to the callback function in the call graph. A presence of such
reference enforces bottom-up traversal order for callback functions in
CG SCC pass manager because callback function logically becomes a callee
of the broker function caller.
Reviewers: jdoerfert, hfinkel, sstefan1, baziotis
Reviewed By: jdoerfert
Subscribers: hiraditya, kuter, sstefan1, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82572
Sometimes SimplifyCFG may decide to perform jump threading. In order
to do it, it follows the following algorithm:
1. Checks if the block is small enough for threading;
2. If yes, inserts a PR Phi relying that the next iteration will remove it
by performing jump threading;
3. The next iteration checks the block again and performs the threading.
This logic has a corner case: inserting the PR Phi increases block's size
by 1. If the block size at first check was max possible, one more Phi will
exceed this size, and we will neither perform threading nor remove the
created Phi node. As result, we will end up with worse IR than before.
This patch fixes this situation by excluding Phis from block size computation.
Excluding Phis from size computation for threading also makes sense by
itself because in case of threadign all those Phis will be removed.
Differential Revision: https://reviews.llvm.org/D81835
Reviewed By: asbirlea, nikic
It's possible for the first loop trip(s) to set the `Changed` Status, and to a
later one to early exit, in which case `Changed` must be return.
Differential Revision: https://reviews.llvm.org/D82753
In https://reviews.llvm.org/D81198, we outlined a number of scenarios
where dropping debug locations is appropriate. Stop issuing an error
when this happens.
Summary:
According to HowToUpdateDebugInfo.rst:
```
Preserving the debug locations of speculated instructions can make
it seem like a condition is true when it's not (or vice versa), which
leads to a confusing single-stepping experience
```
This patch follows the recommendation to drop debug locations on
speculated instructions.
Reviewers: aprantl, davide
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82420
InjectTLIMappings fails to preserve the analysis result of GlobalsAA. Not preserving the analysis might affect benchmark performance. This change fixes this issue.
Patch by: Ryan Santhiraraja <rsanthir@quicinc.com>
Reviewers: fpetrogalli, joerg, fhahn
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D82343
Summary:
As [[ https://bugs.llvm.org/show_bug.cgi?id=45360 | PR45360 ]] reports,
with new cost-model we can sometimes end up being able to expand `udiv`/`urem` instructions.
And that exposes at least one instance of when we do that
regardless of whether or not it is safe to do.
In this particular case, it's `SimplifyIndvar::replaceIVUserWithLoopInvariant()`.
It seems to me, we simply need to check with `isSafeToExpandAt()` first.
The test isn't great. I'm not sure how to make it only run `-indvars`.
Fixes [[ https://bugs.llvm.org/show_bug.cgi?id=45360 | PR45360 ]].
Reviewers: mkazantsev, reames, helloqirun
Reviewed By: mkazantsev
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82108
This reverts commit 29b2c1ca72.
The patch causes the DT verifier failure like:
DominatorTree is different than a freshly computed one!
Not sure the patch itself it wrong but revert to investigate the failure.
Currently we allow peeling of the loops if there is a exiting latch block
and all other exits are blocks ending with deopt.
Actually we want that exit would end up with deopt unconditionally but
it is not required that exit itself ends with deopt.
Reviewers: reames, ashlykov, fhahn, apilipenko, fedor.sergeev
Reviewed By: apilipenko
Subscribers: hiraditya, zzheng, dantrushin, llvm-commits
Differential Revision: https://reviews.llvm.org/D81140
When an invoke instruction is converted to a call its
profile metadata is dropped because it has incompatible
format (see commit 16ad6eeb94).
This patch adds an attempt to convert profile data to
format of the call instruction. This used to work well
before the commit dcfa78a4cc.
Reviewers: reames
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82071
Summary:
this reduces significantly the number of assumes generated without aftecting too much
the information that is preserved. this improves the compile-time cost
of enable-knowledge-retention significantly.
Reviewers: jdoerfert, sstefan1
Reviewed By: jdoerfert
Subscribers: hiraditya, asbirlea, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79650
I don't know anything about debug info, but this seems like more work
should be necessary. This constructs a new IRBuilder and reconstructs
the original divides rather than moving the original.
One problem this has is if a div/rem pair are handled, both end up
with the same debugloc. I'm not sure how to fix this, since this uses
a cache when it sees the same input operands again, which will have
the first instance's location attached.
Summary:
llvm::SplitEdge was failing an assertion that the BasicBlock only had
one successor (for BasicBlocks terminated by CallBrInst, we typically
have multiple successors). It was surprising that the earlier call to
SplitCriticalEdge did not handle the critical edge (there was an early
return). Removing that triggered another assertion relating to creating
a BlockAddress for a BasicBlock that did not (yet) have a parent, which
is a simple order of operations issue in llvm::SplitCriticalEdge (a
freshly constructed BasicBlock must be inserted into a Function's basic
block list to have a parent).
Thanks to @nathanchance for the report.
Fixes: https://github.com/ClangBuiltLinux/linux/issues/1018
Reviewers: craig.topper, jyknight, void, fhahn, efriedma
Reviewed By: efriedma
Subscribers: eli.friedman, rnk, efriedma, fhahn, hiraditya, llvm-commits, nathanchance, srhines
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D81607
The invoke instruction can have profile metadata with branch_weights,
which does not make sense for a call instruction and will be
rejected by the verifier.
Differential revision: https://reviews.llvm.org/D81996
Summary:
this reduces significantly the number of assumes generated without aftecting too much
the information that is preserved. this improves the compile-time cost
of enable-knowledge-retention significantly.
Reviewers: jdoerfert, sstefan1
Reviewed By: jdoerfert
Subscribers: hiraditya, asbirlea, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79650
is not necessary one of them.
Summary: Currently LoopUnrollPass already allow loops with multiple
exiting blocks, but it is only allowed when the loop latch is one of the
exiting blocks.
When the loop latch is not an exiting block, then only single exiting
block is supported.
When possible, the single loop latch or the single exiting block
terminator is optimized to an unconditional branch in the unrolled loop.
This patch allows loops with multiple exiting blocks even if the loop
latch is not one of them. However, the optimization of exiting block
terminator to unconditional branch is not done when there exists more
than one exiting block.
Reviewer: dmgreen, Meinersbur, etiotto, fhahn, efriedma, bmahjour
Reviewed By: efriedma
Subscribers: hiraditya, zzheng, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D81053
This patch adds a new option to CriticalEdgeSplittingOptions to control
whether loop-simplify form must be preserved. It is them used by GVN to
indicate that loop-simplify form does not have to be preserved.
This fixes a crash exposed by 189efe295b.
If the critical edge we are splitting goes from a block inside a loop to
a block outside the loop, splitting the edge will create a new exit
block. As a result, the new block will branch to the original exit
block, which will add a non-loop predecessor, breaking loop-simplify
form. To preserve loop-simplify form, the predecessor blocks of the
original exit are split, but that does not work for blocks with
indirectbr terminators. If preserving loop-simplify form is requested,
bail out , before making any changes.
Reviewers: reames, hfinkel, davide, efriedma
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D81582
Change BasicBlock::removePredecessor to optionally return a vector of
instructions which might be dead. Use this in ConstantFoldTerminator to
delete them if they are dead.
Reapply with a bug fix: don't drop the "!KeepOneInputPHIs" argument when
removePredecessor calls PHINode::removeIncomingValue.
Differential Revision: https://reviews.llvm.org/D80206
Change BasicBlock::removePredecessor to optionally return a vector of
instructions which might be dead. Use this in ConstantFoldTerminator to
delete them if they are dead.
Differential Revision: https://reviews.llvm.org/D80206
[ v1 was reverted by c6ec352a6b due to
modpost failing; v2 fixes this. More info:
https://github.com/ClangBuiltLinux/linux/issues/1045#issuecomment-640381783 ]
This makes -fsanitize=kernel-address emit the correct globals
constructors for the kernel. We had to do the following:
* Disable generation of constructors that rely on linker features such
as dead-global elimination.
* Only instrument globals *not* in explicit sections. The kernel uses
sections for special globals, which we should not touch.
* Do not instrument globals that are prefixed with "__" nor that are
aliased by a symbol that is prefixed with "__". For example, modpost
relies on specially named aliases to find globals and checks their
contents. Unfortunately modpost relies on size stored as ELF debug info
and any padding of globals currently causes the debug info to cause size
reported to be *with* redzone which throws modpost off.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203493
Tested:
* With 'clang/test/CodeGen/asan-globals.cpp'.
* With test_kasan.ko, we can see:
BUG: KASAN: global-out-of-bounds in kasan_global_oob+0xb3/0xba [test_kasan]
* allyesconfig, allmodconfig (x86_64)
Reviewed By: glider
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D81390
- Now all SalvageDebugInfo() calls will mark undef if the salvage
attempt fails.
Reviewed by: vsk, Orlando
Differential Revision: https://reviews.llvm.org/D78369
Summary:
This makes -fsanitize=kernel-address emit the correct globals
constructors for the kernel. We had to do the following:
- Disable generation of constructors that rely on linker features such
as dead-global elimination.
- Only emit constructors for globals *not* in explicit sections. The
kernel uses sections for special globals, which we should not touch.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203493
Tested:
1. With 'clang/test/CodeGen/asan-globals.cpp'.
2. With test_kasan.ko, we can see:
BUG: KASAN: global-out-of-bounds in kasan_global_oob+0xb3/0xba [test_kasan]
Reviewers: glider, andreyknvl
Reviewed By: glider
Subscribers: cfe-commits, nickdesaulniers, hiraditya, llvm-commits
Tags: #llvm, #clang
Differential Revision: https://reviews.llvm.org/D80805
Summary:
In SCEVExpander FactorOutConstant(), when GEP indexing into/over scalable vector,
it is legal for the 'Factor' in a MulExpr to be the size of a scalable vector
instead of a compile-time constant.
Current upstream crash with the test attached.
Reviewers: efriedma, sdesmalen, sanjoy.google, mkazantsev
Reviewed By: efriedma
Subscribers: hiraditya, javed.absar, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D80973
As discussed in https://bugs.llvm.org/show_bug.cgi?id=45951 and
D80584, the name 'tmp' is almost always a bad choice, but we have
a legacy of regression tests with that name because it was baked
into utils/update_test_checks.py.
This change makes -instnamer more consistent (already using "arg"
and "bb", the common LLVM shorthand). And it avoids the conflict
in telling users of the FileCheck script to run "-instnamer" to
create a better regression test and having that cause a warn/fail
in update_test_checks.py.
Prevent `invertCondition` from creating the inversion instruction, in
case the given value is an argument which has already been inverted.
Note that this approach has already been taken in case the given value
is an instruction (and not an argument).
Differential Revision: https://reviews.llvm.org/D80399
Summary: The following code from
/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp can be used by other
transformations:
while (!MergeBlocks.empty()) {
BasicBlock *BB = *MergeBlocks.begin();
BranchInst *Term = dyn_cast<BranchInst>(BB->getTerminator());
if (Term && Term->isUnconditional() &&
L->contains(Term->getSuccessor(0))) {
BasicBlock *Dest = Term->getSuccessor(0);
BasicBlock *Fold = Dest->getUniquePredecessor();
if (MergeBlockIntoPredecessor(Dest, &DTU, LI)) {
// Don't remove BB and add Fold as they are the same BB
assert(Fold == BB);
(void)Fold;
MergeBlocks.erase(Dest);
} else
MergeBlocks.erase(BB);
} else
MergeBlocks.erase(BB);
}
Hence it should be separated into its own utility function.
Authored By: sidbav
Reviewer: Whitney, Meinersbur, asbirlea, dmgreen, etiotto
Reviewed By: asbirlea
Subscribers: hiraditya, zzheng, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D80583
Now that all of the statepoint related routines have classes with isa support, let's cleanup.
I'm leaving the (dead) utitilities in tree for a few days so that I can do the same cleanup downstream without breakage.
code motion
Summary: Currently isSafeToMoveBefore uses DFS numbering for determining
the relative position of instruction and insert point which is not
always correct. This PR proposes the use of Dominator Tree depth for the
same. If a node is at a higher level than the insert point then it is
safe to say that we want to move in the forward direction.
Authored By: RithikSharma
Reviewer: Whitney, nikic, bmahjour, etiotto, fhahn
Reviewed By: Whitney
Subscribers: fhahn, hiraditya, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D80084
This makes sure to correctly register the loop info of the children
of unroll and jammed loops. It re-uses some code from the unroller for
registering subloops.
Differential Revision: https://reviews.llvm.org/D80619
This fixes the output of the check-debugify option.
Without the patch an example of running the option:
$ opt -check-debugify test.ll -S -o testDebugify.ll
CheckModuleDebugifySkipping module without debugify metadata
After the patch:
$ opt -check-debugify test.ll -S -o testDebugify.ll
CheckModuleDebugify: Skipping module without debugify metadata
Differential Revision: https://reviews.llvm.org/D80553
I think the current code dealing with connecting the unrolled iterations
is a bit more complicated than necessary currently. To connect the
unrolled iterations, we have to update the unrolled latch blocks to
branch to the header of the next unrolled iteration.
We need to do this regardless whether the latch is exiting or not.
Additionally, we try to turn the conditional branch in the exiting block
to an unconditional one. This is an optimization only; alternatively we
could leave the conditional branches in place and rely on other passes
to simplify the conditions.
Logically, this is a separate step from connecting the latches to the
headers, but it is convenient to fold them into the same loop, if the
latch is also exiting. For headers (or other non-latch exiting blocks,
this is done separately).
Hopefully the patch with additional comments makes things a bit clearer.
Reviewers: efriedma, dmgreen, hfinkel, Whitney
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D80544
This intrinsic implements IEEE-754 operation roundToIntegralTiesToEven,
and performs rounding to the nearest integer value, rounding halfway
cases to even. The intrinsic represents the missed case of IEEE-754
rounding operations and now llvm provides full support of the rounding
operations defined by the standard.
Differential Revision: https://reviews.llvm.org/D75670
Summary:
Added a new IRCanonicalizer pass which aims to transform LLVM modules into
a canonical form by reordering and renaming instructions while preserving the
same semantics. The canonicalizer makes it easier to spot semantic differences
when diffing two modules which have undergone different passes.
Presentation: https://www.youtube.com/watch?v=c9WMijSOEUg
Reviewed by: plotfi
Differential Revision: https://reviews.llvm.org/D66029
In case the then-path of an if-region is empty, then merging with the
else-path should be handled with the inverse of the condition (leading
to that path).
Fix PR37662
Differential Revision: https://reviews.llvm.org/D78881
Summary:
Currently, `rewriteLoopExitValues()`'s logic is roughly as following:
> Loop over each incoming value in each PHI node.
> Query whether the SCEV for that incoming value is high-cost.
> Expand the SCEV.
> Perform sanity check (`isValidRewrite()`, D51582)
> Record the info
> Afterwards, see if we can drop the loop given replacements.
> Maybe perform replacements.
The problem is that we interleave SCEV cost checking and expansion.
This is A Problem, because `isHighCostExpansion()` takes special care
to not bill for the expansions that were already expanded, and we can reuse.
While it makes sense in general - if we know that we will expand some SCEV,
all the other SCEV's costs should account for that, which might cause
some of them to become non-high-cost too, and cause chain reaction.
But that isn't what we are doing here. We expand *all* SCEV's, unconditionally.
So every next SCEV's cost will be affected by the already-performed expansions
for previous SCEV's. Even if we are not planning on keeping
some of the expansions we performed.
Worse yet, this current "bonus" depends on the exact PHI node
incoming value processing order. This is completely wrong.
As an example of an issue, see @dmajor's `pr45835.ll` - if we happen to have
a PHI node with two(!) identical high-cost incoming values for the same basic blocks,
we would decide first time around that it is high-cost, expand it,
and immediately decide that it is not high-cost because we have an expansion
that we could reuse (because we expanded it right before, temporarily),
and replace the second incoming value but not the first one;
thus resulting in a broken PHI.
What we instead should do for now, is not perform any expansions
until after we've queried all the costs.
Later, in particular after `isValidRewrite()` is an assertion (D51582)
we could improve upon that, but in a more coherent fashion.
See [[ https://bugs.llvm.org/show_bug.cgi?id=45835 | PR45835 ]]
Reviewers: dmajor, reames, mkazantsev, fhahn, efriedma
Reviewed By: dmajor, mkazantsev
Subscribers: smeenai, nikic, hiraditya, javed.absar, llvm-commits, dmajor
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79787
Hide the method that allows setting probability for particular edge
and introduce a public method that sets probabilities for all
outgoing edges at once.
Setting individual edge probability is error prone. More over it is
difficult to check that the total probability is 1.0 because there is
no easy way to know when the user finished setting all
the probabilities.
Related bug is fixed in BranchProbabilityInfo::calcMetadataWeights().
Changing unreachable branch probabilities to raw(1) and distributing
the rest (oldProbability - raw(1)) over the reachable branches could
introduce total probability inaccuracy bigger than 1/numOfBranches.
Reviewers: yamauchi, ebrevnov
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79396
Summary:
If an induction variable is frozen and used, SCEV yields imprecise result
because it doesn't say anything about frozen variables.
Due to this reason, performance degradation happened after
https://reviews.llvm.org/D76483 is merged, causing
SCEV yield imprecise result and preventing LSR to optimize a loop.
The suggested solution here is to add a pass which canonicalizes frozen variables
inside a loop. To be specific, it pushes freezes out of the loop by freezing
the initial value and step values instead & dropping nsw/nuw flags from instructions used by freeze.
This solution was also mentioned at https://reviews.llvm.org/D70623 .
Reviewers: spatel, efriedma, lebedev.ri, fhahn, jdoerfert
Reviewed By: fhahn
Subscribers: nikic, mgorny, hiraditya, javed.absar, llvm-commits, sanwou01, nlopes
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77523
SCEVExpander modifies the underlying function so it is more suitable in
Transforms/Utils, rather than Analysis. This allows using other
transform utils in SCEVExpander.
This patch was originally committed as b8a3c34eee, but broke the
modules build, as LoopAccessAnalysis was using the Expander.
The code-gen part of LAA was moved to lib/Transforms recently, so this
patch can be landed again.
Reviewers: sanjoy.google, efriedma, reames
Reviewed By: sanjoy.google
Differential Revision: https://reviews.llvm.org/D71537
After D76797 the dominator tree is no longer used in LVI, so we
can remove it as a pass dependency, and also get rid of the
dominator tree enabling/disabling logic in JumpThreading.
Apart from cleaning up the code, this also clarifies LVI
cache consistency, in that the LVI cache can no longer
depend on whether the DT was or wasn't enabled due to
pending DT updates at any given time.
Differential Revision: https://reviews.llvm.org/D76985
We already check hasNoNaNs and that x is finite and strictly positive.
That only leaves the following special cases (taken from the Linux man
page for pow):
If x is +1, the result is 1.0 (even if y is a NaN).
If the absolute value of x is less than 1, and y is negative infinity, the result is positive infinity.
If the absolute value of x is greater than 1, and y is negative infinity, the result is +0.
If the absolute value of x is less than 1, and y is positive infinity, the result is +0.
If the absolute value of x is greater than 1, and y is positive infinity, the result is positive infinity.
The first case is handled elsewhere, and this transformation preserves
all the others, so there is no need to limit it to hasNoInfs.
Differential Revision: https://reviews.llvm.org/D79409
Summary:
When a loop has multiple backedges, loop simplification attempts to
separate them out into nested loops. This results in incorrect control
flow in the presence of some functions like a GPU barrier. This change
skips the transformation when such "convergent" function calls are
present in the loop body.
Reviewed By: nhaehnle
Differential Revision: https://reviews.llvm.org/D80078
Summary:
When salvaging a dead zext instruction, append a convert operation to
the DIExpressions of the debug uses of the instruction, to prevent the
salvaged value from being sign-extended.
I confirmed that lldb prints out the correct unsigned result for "f" in
the example from PR45923 with this changed applied.
rdar://63246143
Reviewers: aprantl, jmorse, chrisjackson, davide
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D80034
Along the lines of D77454 and D79968. Unlike loads and stores, the
default alignment is getPrefTypeAlign, to match the existing handling in
various places, including SelectionDAG and InstCombine.
Differential Revision: https://reviews.llvm.org/D80044
This reverts commit 454de99a6f.
The problem was that one of the ctor arguments of CallAnalyzer was left
to be const std::function<>&. A function_ref was passed for it, and then
the ctor stored the value in a function_ref field. So a std::function<>
would be created as a temporary, and not survive past the ctor
invocation, while the field would.
Tested locally by following https://github.com/google/sanitizers/wiki/SanitizerBotReproduceBuild
Original Differential Revision: https://reviews.llvm.org/D79917
This is D77454, except for stores. All the infrastructure work was done
for loads, so the remaining changes necessary are relatively small.
Differential Revision: https://reviews.llvm.org/D79968
This has been duplicated since before
2372a193ba, but that commit has it
appearing twice in the space of 10 lines of the same function body. It
could also be hoisted up to the point just after where the last
special-case is considered, but I want to keep the intent of the
original authors.
Committed as obvious without a review.
The "null-pointer-is-valid" attribute needs to be checked by many
pointer-related combines. To make the check more efficient, convert
it from a string into an enum attribute.
In the future, this attribute may be replaced with data layout
properties.
Differential Revision: https://reviews.llvm.org/D78862
Summary:
This change exposes the vector name mangling with LLVM ISA (used as part
of vector-function-abi-variant) as a utility.
This can then be used by front-ends that add this attribute.
Note that all parameters passed in to the function will be mangled with
the "v" token to identify that they are of of vector type. So, it is the
responsibility of the caller to confirm that all parameters in the
vectorized variant is of vector type.
Added unit test to show vector name mangling.
Reviewed-By: fpetrogalli, simoll
Differential Revision: https://reviews.llvm.org/D79867
Summary:
Replacing uses of std::function pointers or refs, or Optional, to
function_ref, since the usage pattern allows that. If the function is
optional, using a default parameter value (nullptr). This led to a few
parameter reshufles, to push all optionals to the end of the parameter
list.
Reviewers: davidxl, dblaikie
Subscribers: arsenm, jvesely, nhaehnle, eraman, hiraditya, haicheng, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79917
Summary:
Analyses that are statefull should not be retrieved through a proxy from
an outer IR unit, as these analyses are only invalidated at the end of
the inner IR unit manager.
This patch disallows getting the outer manager and provides an API to
get a cached analysis through the proxy. If the analysis is not
stateless, the call to getCachedResult will assert.
Reviewers: chandlerc
Subscribers: mehdi_amini, eraman, hiraditya, zzheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72893
Hide the method that allows setting probability for particular
edge and introduce a public method that sets probabilities for
all outgoing edges at once.
Setting individual edge probability is error prone. More over
it is difficult to check that the total probability is 1.0
because there is no easy way to know when the user finished
setting all the probabilities.
Reviewers: yamauchi, ebrevnov
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79396
We want to add a way to avoid merging identical calls so as to keep the
separate debug-information for those calls. There is also an asan
usecase where having this attribute would be beneficial to avoid
alternative work-arounds.
Here is the link to the feature request:
https://bugs.llvm.org/show_bug.cgi?id=42783.
`nomerge` is different from `noline`. `noinline` prevents function from
inlining at callsites, but `nomerge` prevents multiple identical calls
from being merged into one.
This patch adds `nomerge` to disable the optimization in IR level. A
followup patch will be needed to let backend understands `nomerge` and
avoid tail merge at backend.
Reviewed By: asbirlea, rnk
Differential Revision: https://reviews.llvm.org/D78659
Summary:
this patch fixe crash/asserts found in the test-suite.
the AssumeptionCache cannot be assumed to have all assumes contrary to what i tought.
prevent generation of information for terminators, because this can create broken IR in transfromation where we insert the new terminator before removing the old one.
Reviewers: jdoerfert
Reviewed By: jdoerfert
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79458
don't span their entire scope.
The previous commit (6d1c40c171) is an older version of the test.
Reviewed By: aprantl, vsk
Differential Revision: https://reviews.llvm.org/D79573
Summary:
The assume builder was non-deterministic when working on unamed values.
this patch fixes this.
Reviewers: jdoerfert
Reviewed By: jdoerfert
Subscribers: hiraditya, mgrang, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78616
Summary: with this patch the assume salvageKnowledge will not generate assume if all knowledge is already available in an assume with valid context. assume bulider can also in some cases update an existing assume with better information.
Reviewers: jdoerfert
Reviewed By: jdoerfert
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78014
Currently LAA's uses of ScalarEvolutionExpander blocks moving the
expander from Analysis to Transforms. Conceptually the expander does not
fit into Analysis (it is only used for code generation) and
runtime-check generation also seems to be better suited as a
transformation utility.
Reviewers: Ayal, anemet
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D78460
Summary:
If the only use of a value is a start or end lifetime intrinsic then mark the intrinsic as trivially dead. This should allow for that value to then be removed as well.
Currently, this only works for allocas, globals, and arguments.
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79355
FoldBranchToCommonDest clones instructions to a different basic block,
but handles debug intrinsics in a separate path. Previously, when
cloning debug intrinsics, their operands were not updated to reference
the correct cloned values. As a result, we would emit debug.value
intrinsics with broken operand references which are discarded in later
passes. This leads to incorrect debuginfo that reports incorrect values
for variables.
Fix this by remapping debug intrinsic operands when cloning them.
Fixes https://bugs.llvm.org/show_bug.cgi?id=45667.
Differential Revision: https://reviews.llvm.org/D79602
Splitting critical edges for indirect branches
the SplitIndirectBrCriticalEdges() function may break branch
probabilities if target basic block happens to have unset
a probability for any of its successors. That is because in
such cases the getEdgeProbability(Target) function returns
probability 1/NumOfSuccessors and it is called after Target
was split (thus Target has a single successor). As the result
the correspondent successor of the split block gets
probability 100% but 1/NumOfSuccessors is expected (or better
be left unset).
Reviewers: yamauchi
Differential Revision: https://reviews.llvm.org/D78806
loop nest.
Summary: As discussed in https://reviews.llvm.org/D73129.
Example
Before unroll and jam:
for
A
for
B
for
C
D
E
After unroll and jam (currently):
for
A
A'
for
B
for
C
D
B'
for
C'
D'
E
E'
After unroll and jam (Ideal):
for
A
A'
for
B
B'
for
C
C'
D
D'
E
E'
This is the first patch to change unroll and jam to work in the ideal
way.
This patch change the safety checks needed to make sure is safe to
unroll and jam in the ideal way.
Reviewer: dmgreen, jdoerfert, Meinersbur, kbarton, bmahjour, etiotto
Reviewed By: Meinersbur
Subscribers: fhahn, hiraditya, zzheng, llvm-commits, anhtuyen, prithayan
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D76132
Summary:
If the only use of a value is a start or end lifetime intrinsic then mark the intrinsic as trivially dead. This should allow for that value to then be removed as well.
Currently, this only works for allocas, globals, and arguments.
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79355
We check that C is finite and strictly positive, but there's no need to
check that it's normal too. exp2 should be just as accurate on denormals
as pow is.
Differential Revision: https://reviews.llvm.org/D79413
I don't think there's any good reason not to do this transformation when
the pow has multiple uses.
Differential Revision: https://reviews.llvm.org/D79407
optimizePow does not create any new calls to pow, so it should work
regardless of whether the pow library function is available. This allows
it to optimize the llvm.pow intrinsic on targets with no math library.
Based on a patch by Tim Renouf.
Differential Revision: https://reviews.llvm.org/D68231
When the shufflevector mask operand was converted into special
instruction data, the FunctionComparator was not updated to
account for this. As such, MergeFuncs will happily merge
shufflevectors with different masks.
This fixes https://bugs.llvm.org/show_bug.cgi?id=45773.
Differential Revision: https://reviews.llvm.org/D79261
In D74183 clang started emitting alignment for sret parameters
unconditionally. This caused a 1.5% compile-time regression on
tramp3d-v4. The reason is that we now generate many instance of IR like
%ptrint = ptrtoint %class.GuardLayers* %guards_m to i64
%maskedptr = and i64 %ptrint, 3
%maskcond = icmp eq i64 %maskedptr, 0
tail call void @llvm.assume(i1 %maskcond)
to preserve the alignment information during inlining. Based on IR
analysis, these assumptions also regress optimization. The attached
phase ordering test case illustrates two issues: One are instruction
count based optimization heuristics, which are affected by the four
additional instructions of the assumption. The other is blocking of
SROA due to ptrtoint casts (PR45763).
We already encountered the same problem in Rust, where we (unlike
Clang) generally prefer to emit alignment information absolutely
everywhere it is available. We were only able to do this after
hardcoding -preserve-alignment-assumptions-during-inlining=false,
because we were seeing significant optimization and compile-time
regressions otherwise.
This patch disables -preserve-alignment-assumptions-during-inlining
by default, because we should not be punishing people for adding
more alignment annotations.
Once the assume bundle work shakes out and we can represent (and use)
alignment assumptions using assume bundles, it should be possible to
re-enable this with reduced overhead.
Differential Revision: https://reviews.llvm.org/D76886
This allows forward declarations of PointerCheck, which in turn reduce
the number of times LoopAccessAnalysis needs to be included.
Ultimately this helps with moving runtime check generation to
Transforms/Utils/LoopUtils.h, without having to include it there.
Reviewers: anemet, Ayal
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D78458
There are several different types of cost that TTI tries to provide
explicit information for: throughput, latency, code size along with
a vague 'intersection of code-size cost and execution cost'.
The vectorizer is a keen user of RecipThroughput and there's at least
'getInstructionThroughput' and 'getArithmeticInstrCost' designed to
help with this cost. The latency cost has a single use and a single
implementation. The intersection cost appears to cover most of the
rest of the API.
getUserCost is explicitly called from within TTI when the user has
been explicit in wanting the code size (also only one use) as well
as a few passes which are concerned with a mixture of size and/or
a relative cost. In many cases these costs are closely related, such
as when multiple instructions are required, but one evident diverging
cost in this function is for div/rem.
This patch adds an argument so that the cost required is explicit,
so that we can make the important distinction when necessary.
Differential Revision: https://reviews.llvm.org/D78635
This method has been commented as deprecated for a while. Remove
it and replace all uses with the equivalent getCalledOperand().
I also made a few cleanups in here. For example, to removes use
of getElementType on a pointer when we could just use getFunctionType
from the call.
Differential Revision: https://reviews.llvm.org/D78882
Add llvm.call.preallocated.{setup,arg} instrinsics.
Add "preallocated" operand bundle which takes a token produced by llvm.call.preallocated.setup.
Add "preallocated" parameter attribute, which is like byval but without the copy.
Verifier changes for these IR constructs.
See https://github.com/rnk/llvm-project/blob/call-setup-docs/llvm/docs/CallSetup.md
Subscribers: hiraditya, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D74651
Summary:
refactor assume bulider for the next patch.
the assume builder now generate only one assume per attribute kind and per value they are on. to do this it takes the highest. this is desirable because currently, for all attributes the higest value is the most valuable.
Reviewers: jdoerfert
Reviewed By: jdoerfert
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78013
We should only skip `lifetime` and `dbg` intrinsics when searching for users.
Other intrinsics are legit users that can't be ignored.
Without this fix, the testcase would result in an invalid IR. `memcpy`
will have a reference to the, now, external value (local to the
extracted loop function).
Fix PR42194
Differential Revision: https://reviews.llvm.org/D78749
Summary:
Teach MachineDebugify how to insert DBG_VALUE instructions. This can
help find bugs causing CodeGen differences when debug info is present.
DBG_VALUE instructions are only emitted when -debugify-level is set to
locations+variables.
There is essentially no attempt made to match up DBG_VALUE register
operands with the local variables they ought to correspond to. I'm not
sure how to improve the situation. In some cases (MachineMemOperand?)
it's possible to find the IR instruction a MachineInstr corresponds to,
but in general this seems to call for "undoing" the work done by ISel.
Reviewers: dsanders, aprantl
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78135
Summary:
When an irreducible SCC is converted into a new natural loop, existing
loops included in that SCC now become children of the new loop. The
logic that moves these loops from the parent loop to the new loop
invoked undefined behaviour when it modified the container that it was
iterating over. Fixed this by first extracting all the loops that are
to be removed from the parent.
Fixes bug 45623.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D78544
With clang option -funique-internal-linkage-symbols, symbols with
internal linkage get names with the module hash appended.
Differential Revision: https://reviews.llvm.org/D78243
The recently added Instruction::comesBefore can be used instead of
OrderedInstructions.
Reviewers: rnk, nikic, efriedma
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D78452
Most of the includes in LoopUtils.h are not required in the header and
they can be replaced by forward declarations.
Unfortunately includes of TargetTransformInfo.h and IVDescriptors.h pull
in a bunch of additional things, but there is no easy way to get rid of
them at the moment I think.
When running IPSCCP on a module with many small functions, memory
usage is dominated by PredicateInfo, which is a huge structure
(partially due to some unfortunate nested SmallVector use). However,
most of it is actually only temporary state needed to build
predicate info, and does not need to be retained after initial
construction.
This patch factors out the predicate building logic and state
into a separate PrediceInfoBuilder, with the extra bonus that
it does not need to live in the header anymore.
Differential Revision: https://reviews.llvm.org/D78326
We previously clamped the trailing zero count to 31 bits. And
then clamped the final alignment to MaximumAlignment which is
1 << 29.
This patch simplifies this to just clamp the trailing zero to
29 using MaxAlignmentExponent.
I was looking into changing this function to use Align/MaybeAlign
and noticed this.
Differential Revision: https://reviews.llvm.org/D78418
I uploaded the old version accidentally instead of the one with these
minor adjustments requested by the reviewers.
Differential Revision: https://reviews.llvm.org/D77855
Summary:
We can and should remove deleted nodes from their respective SCCs. We
did not do this before and this was a potential problem even though I
couldn't locally trigger an issue. Since the `DeleteNode` would assert
if the node was not in the SCC, we know we only remove nodes from their
SCC and only once (when run on all the Attributor tests).
Reviewers: lebedev.ri, hfinkel, fhahn, probinson, wristow, loladiro, sstefan1, uenoku
Subscribers: hiraditya, bollu, uenoku, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77855
Summary:
While it is uncommon that the ExternalCallingNode needs to be updated,
it can happen. It is uncommon because most functions listed as callees
have external linkage, modifying them is usually not allowed. That said,
there are also internal functions that have, or better had, their
"address taken" at construction time. We conservatively assume various
uses cause the address "to be taken". Furthermore, the user might have
become dead at some point. As a consequence, transformations, e.g., the
Attributor, might be able to replace a function that is listed
as callee of the ExternalCallingNode.
Since there is no function corresponding to the ExternalCallingNode, we
did just remove the node from the callee list if we replaced it (so
far). Now it would be preferable to replace it if needed and remove it
otherwise. However, removing the node has implications on the CGSCC
iteration. Locally, that caused some other nodes to be never visited
but it is for sure possible other (bad) side effects can occur. As it
seems conservatively safe to keep the new node in the callee list we
will do that for now.
Reviewers: lebedev.ri, hfinkel, fhahn, probinson, wristow, loladiro, sstefan1, uenoku
Subscribers: hiraditya, bollu, uenoku, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77854
Summary:
The old code did eliminate references from and to functions that were
about to be deleted only just before we deleted them. This can cause
references from other functions that are supposed to be deleted to still
exist, depending on the order. If the functions form a strongly
connected component the problem manifests regardless of the order in
which we try to actually delete the functions.
This patch introduces a two step deletion. First we remove all
references and then we delete the function. Note that this only affects
the old call graph. There should not be any functional changes if no old
style call graph was given.
To test this we delete two strongly connected functions instead of one
in an existing test.
Reviewers: hfinkel
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77975
This is related to commit 8c11bc0cd0
which introduces the FixIrreducible pass. The warning seems hard to
reproduce locally. The latest attempt ought to work.
An irreducible SCC is one which has multiple "header" blocks, i.e., blocks
with control-flow edges incident from outside the SCC. This pass converts an
irreducible SCC into a natural loop by introducing a single new header
block and redirecting all the edges on the original headers to this
new block.
This is a useful workaround for a limitation in the structurizer
which, which produces incorrect control flow in the presence of
irreducible regions. The AMDGPU backend provides an option to
enable this pass before the structurizer, which may eventually be
enabled by default.
Reviewed By: nhaehnle
Differential Revision: https://reviews.llvm.org/D77198
This restores commit 2ada8e2525.
Originally reverted with commit 44e09b59b8.
This reverts commit 2ada8e2525.
Buildbots produced compilation errors which I was not able to quickly
reproduce locally. Need more time to investigate.
An irreducible SCC is one which has multiple "header" blocks, i.e., blocks
with control-flow edges incident from outside the SCC. This pass converts an
irreducible SCC into a natural loop by introducing a single new header
block and redirecting all the edges on the original headers to this
new block.
This is a useful workaround for a limitation in the structurizer
which, which produces incorrect control flow in the presence of
irreducible regions. The AMDGPU backend provides an option to
enable this pass before the structurizer, which may eventually be
enabled by default.
Reviewed By: nhaehnle
Differential Revision: https://reviews.llvm.org/D77198
Summary:
Share logic to strip debugify metadata between the IR and MIR level
debugify passes. This makes it simpler to hunt for bugs by diffing IR
with vs. without -debugify-each turned on.
As a drive-by, fix an issue causing CallGraphNodes to become invalid
when a dead llvm.dbg.value prototype is deleted.
Reviewers: dsanders, aprantl
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77915
Summary: change assumption cache to store an assume along with an index to the operand bundle containing the knowledge.
Reviewers: jdoerfert, hfinkel
Reviewed By: jdoerfert
Subscribers: hiraditya, mgrang, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77402
Summary:
Updated CallPromotionUtils and impacted sites. Parameters that are
expected to be non-null, and return values that are guranteed non-null,
were replaced with CallBase references rather than pointers.
Left FIXME in places where more changes are facilitated by CallBase, but
aren't CallSites: Instruction* parameters or return values, for example,
where the contract that they are actually CallBase values.
Reviewers: davidxl, dblaikie, wmi
Reviewed By: dblaikie
Subscribers: arsenm, jvesely, nhaehnle, eraman, hiraditya, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77930
Summary:
Remove usages of asserting vector getters in Type in preparation for the
VectorType refactor. The existence of these functions complicates the
refactor while adding little value.
Reviewers: rriddle, sdesmalen, efriedma
Reviewed By: sdesmalen
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77260
Dead constants might be left when a function is replaced, we can
gracefully handle this case and avoid complexity for the users who would
see an assertion otherwise.
Summary:
Re-used the IR-level debugify for the most part. The MIR-level code then
adds locations to the MachineInstrs afterwards based on the LLVM-IR debug
info.
It's worth mentioning that the resulting locations make little sense as
the range of line numbers used in a Function at the MIR level exceeds that
of the equivelent IR level function. As such, MachineInstrs can appear to
originate from outside the subprogram scope (and from other subprogram
scopes). However, it doesn't seem worth worrying about as the source is
imaginary anyway.
There's a few high level goals this pass works towards:
* We should be able to debugify our .ll/.mir in the lit tests without
changing the checks and still pass them. I.e. Debug info should not change
codegen. Combining this with a strip-debug pass should enable this. The
main issue I ran into without the strip-debug pass was instructions with MMO's and
checks on both the instruction and the MMO as the debug-location is
between them. I currently have a simple hack in the MIRPrinter to
resolve that but the more general solution is a proper strip-debug pass.
* We should be able to test that GlobalISel does not lose debug info. I
recently found that the legalizer can be unexpectedly lossy in seemingly
simple cases (e.g. expanding one instr into many). I have a verifier
(will be posted separately) that can be integrated with passes that use
the observer interface and will catch location loss (it does not verify
correctness, just that there's zero lossage). It is a little conservative
as the line-0 locations that arise from conflicts do not track the
conflicting locations but it can still catch a fair bit.
Depends on D77439, D77438
Reviewers: aprantl, bogner, vsk
Subscribers: mgorny, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77446
dso_local leads to direct access even if the definition is not within this compilation unit (it is
still in the same linkage unit). On ELF, such a relocation (e.g. R_X86_64_PC32) referencing a
STB_GLOBAL STV_DEFAULT object can cause a linker error in a -shared link.
If the linkage is changed to available_externally, the dso_local flag should be dropped, so that no
direct access will be generated.
The current behavior is benign, because -fpic does not assume dso_local
(clang/lib/CodeGen/CodeGenModule.cpp:shouldAssumeDSOLocal).
If we do that for -fno-semantic-interposition (D73865), there will be an
R_X86_64_PC32 linker error without this patch.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D74751
Now that we have scalable vectors, there's a distinction that isn't
getting captured in the original SequentialType: some vectors don't have
a known element count, so counting the number of elements doesn't make
sense.
In some cases, there's a better way to express the commonality using
other methods. If we're dealing with GEPs, there's GEP methods; if we're
dealing with a ConstantDataSequential, we can query its element type
directly.
In the relatively few remaining cases, I just decided to write out
the type checks. We're talking about relatively few places, and I think
the abstraction doesn't really carry its weight. (See thread "[RFC]
Refactor class hierarchy of VectorType in the IR" on llvmdev.)
Differential Revision: https://reviews.llvm.org/D75661
Summary:
It can be helpful to test behaviour w.r.t locations without having DEBUG_VALUE
around. In particular, because DEBUG_VALUE has the potential to change CodeGen
behaviour (e.g. hasOneUse() vs hasOneNonDbgUse()) while locations generally
don't.
Reviewers: aprantl, bogner
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77438
This patch builds upon D76140 by updating metadata on pointer typed
loads in inlined functions, when the load is the return value, and the
callsite contains return attributes which can be updated as metadata on
the load.
Added test cases show this for nonnull, dereferenceable,
dereferenceable_or_null
Reviewed-By: jdoerfert
Differential Revision: https://reviews.llvm.org/D76792
As discussed in post-commit review in https://reviews.llvm.org/D73501
if the goal of this is to help vectorizer, then we should actually
be teaching vectorizer to do this, because right now this rewrite
is still budget-limited, which isn't what we'd want.
Additionally, while the rest of the patch series was universally profitable,
this particular patch is reportedly (https://reviews.llvm.org/D73501#1905171)
exposing cost-modeling issues on ARM.
So let's just back this particular patch out. Once there's an undo transform,
this could be considered for reintegration.
This reverts commit 44edc6fd2c.
Consider a callee function that has a call (C) within it which feeds
into the return. When we inline that callee into a callsite that has
return attributes, we can backward propagate valid attributes to the
call (C) within that inlined callee body.
This is safe to do so only if we can guarantee transfer of execution to
successor in the window of instructions between return value (i.e. the
call C) and the return instruction.
Also, this is valid only for attributes which are a property of a
callsite and not those that are not dependent on the ABI, or a property
of the call itself.
Reviewed-By: reames, jdoerfert
Differential Revision: https://reviews.llvm.org/D76140
Kazu Hirata