Summary:
When splitting musttail calls, the split blocks' original terminators
get removed; inform the DTU when this happens.
Also add a testcase that fails an assertion in the DTU without this fix.
Reviewers: fhahn, junbuml
Reviewed By: fhahn
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D55027
llvm-svn: 347872
1. The variables were confusing: 'C' typically refers to a constant, but here it was the Cmp.
2. Formatting violations.
3. Simplify code to return true/false constant.
llvm-svn: 347868
This reverts commits r347776 and r347778.
The first one, r347776, caused significant compile time regressions
for certain input files, see PR39836 for details.
llvm-svn: 347867
This commit caused failures because it failed to correctly handle cases where
we hoist a phi, then hoist a use of that phi, then have to rehoist that use. We
need to make sure that we rehoist the use to _after_ the hoisted phi, which we
do by always rehoisting to the immediate dominator instead of just rehoisting
everything to the original preheader.
An option is also added to control whether control flow is hoisted, which is
off in this commit but will be turned on in a subsequent commit.
Differential Revision: https://reviews.llvm.org/D52827
llvm-svn: 347776
It fixes a bug that doesn't update Phi inputs of the only live successor that
is in the list of block's successors more than once.
Thanks @uabelho for finding this.
Differential Revision: https://reviews.llvm.org/D54849
Reviewed By: anna
llvm-svn: 347640
OriginalOp of a Predicate refers to the original IR value,
before renaming. While solving in IPSCCP, we have to use
the operand of the ssa_copy instead, to avoid missing
updates for nested conditions on the same IR value.
Fixes PR39772.
llvm-svn: 347524
When removing edges, we also update Phi inputs and may end up removing
a Phi if it has only one input. We should not do it for edges that leave the current
loop because these Phis are LCSSA Phis and need to be preserved.
Thanks @dmgreen for finding this!
Differential Revision: https://reviews.llvm.org/D54841
llvm-svn: 347484
This patch fixes PR39695.
The original LoopSink only considers memory alias in loop body. But PR39695 shows that instructions following sink candidate in preheader should also be checked. This is a conservative patch, it simply adds whole preheader block to alias set. It may lose some optimization opportunity, but I think that is very rare because: 1 in the most common case st/ld to the same address, the load should already be optimized away. 2 usually preheader is not very large.
Differential Revision: https://reviews.llvm.org/D54659
llvm-svn: 347325
The initial version of patch lacked Phi nodes updates in destinations of removed
edges. This version contains this update and tests on this situation.
Differential Revision: https://reviews.llvm.org/D54021
llvm-svn: 347289
The general approach taken is to make note of loop invariant branches, then when
we see something conditional on that branch, such as a phi, we create a copy of
the branch and (empty versions of) its successors and hoist using that.
This has no impact by itself that I've been able to see, as LICM typically
doesn't see such phis as they will have been converted into selects by the time
LICM is run, but once we start doing phi-to-select conversion later it will be
important.
Differential Revision: https://reviews.llvm.org/D52827
llvm-svn: 347190
This patch introduces infrastructure and the simplest case for constant-folding
of branch and switch instructions within loop into unconditional branches.
It is useful as a cleanup for such passes as loop unswitching that sometimes
produce such branches.
Only the simplest case supported in this patch: after the folding, no block
should become dead or stop being part of the loop. Support for more
sophisticated cases will go separately in follow-up patches.
Differential Revision: https://reviews.llvm.org/D54021
Reviewed By: anna
llvm-svn: 347183
Fix all of the missing debug location errors in CVP found by debugify.
This includes the missing-location-after-udiv-truncation case described
in llvm.org/PR38178.
llvm-svn: 347147
We need to control exponential behavior of loop-unswitch so we do not get
run-away compilation.
Suggested solution is to introduce a multiplier for an unswitch cost that
makes cost prohibitive as soon as there are too many candidates and too
many sibling loops (meaning we have already started duplicating loops
by unswitching).
It does solve the currently known problem with compile-time degradation
(PR 39544).
Tests are built on top of a recently implemented CHECK-COUNT-<num>
FileCheck directives.
Reviewed By: chandlerc, mkazantsev
Differential Revision: https://reviews.llvm.org/D54223
llvm-svn: 347097
This patch updates DuplicateInstructionsInSplitBetween to update a DTU
instead of applying updates to the DT directly.
Given that there only are 2 users, also updated them in this patch to
avoid churn.
I slightly moved the code in CallSiteSplitting around to reduce the
places where we have to pass in DTU. If necessary, I could split those
changes in a separate patch.
This fixes missing DT updates when dealing with musttail calls in
CallSiteSplitting, by using DTU->deleteBB.
Reviewers: junbuml, kuhar, NutshellySima, indutny, brzycki
Reviewed By: NutshellySima
llvm-svn: 346769
Summary:
This patch introduces DebugCounter into ConstProp pass at per-transformation level.
It will provide an option to skip first n or stop after n transformations for the whole ConstProp pass.
This will make debug easier for the pass, also providing chance to do transformation level bisecting.
Reviewers: davide, fhahn
Reviewed By: fhahn
Subscribers: llozano, george.burgess.iv, llvm-commits
Differential Revision: https://reviews.llvm.org/D50094
llvm-svn: 346720
This patch relaxes overconservative checks on whether or not we could write
memory before we execute an instruction. This allows us to hoist guards out of
loops even if they are not in the header block.
Differential Revision: https://reviews.llvm.org/D50891
Reviewed By: fedor.sergeev
llvm-svn: 346643
ComputeValueKnownInPredecessors has a "visited" set to prevent infinite
loops, since a value can be visited more than once. However, the
implementation didn't prevent the algorithm from taking exponential
time. Instead of removing elements from the RecursionSet one at a time,
we should keep around the whole set until
ComputeValueKnownInPredecessors finishes, then discard it.
The testcase is synthetic because I was having trouble effectively
reducing the original. But it's basically the same idea.
Instead of failing, we could theoretically cache the result instead.
But I don't think it would help substantially in practice.
Differential Revision: https://reviews.llvm.org/D54239
llvm-svn: 346562
After D45330, Dominators are required for IPSCCP and can be preserved.
This patch preserves DominatorTreeAnalysis in the new pass manager. AFAIK the legacy pass manager cannot preserve function analysis required by a module analysis.
Reviewers: davide, dberlin, chandlerc, efriedma, kuhar, NutshellySima
Reviewed By: chandlerc, kuhar, NutshellySima
Differential Revision: https://reviews.llvm.org/D47259
llvm-svn: 346486
We can stop recording conditions once we reached the immediate dominator
for the block containing the call site. Conditions in predecessors of the
that node will be the same for all paths to the call site and splitting
is not beneficial.
This patch makes CallSiteSplitting dependent on the DT anlysis. because
the immediate dominators seem to be the easiest way of finding the node
to stop at.
I had to update some exiting tests, because they were checking for
conditions that were true/false on all paths to the call site. Those
should now be handled by instcombine/ipsccp.
Reviewers: davide, junbuml
Reviewed By: junbuml
Differential Revision: https://reviews.llvm.org/D44627
llvm-svn: 346483
This patch adds logic to detect reductions across the inner and outer
loop by following the incoming values of PHI nodes in the outer loop. If
the incoming values take part in a reduction in the inner loop or come
from outside the outer loop, we found a reduction spanning across inner
and outer loop.
With this change, ~10% more loops are interchanged in the LLVM
test-suite + SPEC2006.
Fixes https://bugs.llvm.org/show_bug.cgi?id=30472
Reviewers: mcrosier, efriedma, karthikthecool, davide, hfinkel, dmgreen
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D43245
llvm-svn: 346438
The patch has been reverted because it ended up prohibiting propagation
of a constant to exit value. For such values, we should skip all checks
related to hard uses because propagating a constant is always profitable.
Differential Revision: https://reviews.llvm.org/D53691
llvm-svn: 346397
LSR reassociates constants as unfolded offsets when the constants fit as
immediate add operands, which currently prevents such constants from being
combined later with loop invariant registers.
This patch modifies GenerateCombinations() to generate a second formula which
includes the unfolded offset in the combined loop-invariant register.
This commit fixes a bug in the original patch (committed at r345114, reverted
at r345123).
Differential Revision: https://reviews.llvm.org/D51861
llvm-svn: 346390
When partial unswitch operates on multiple conditions at once, .e.g:
if (Cond1 || Cond2 || NonInv) ...
it should infer (and replace) values for individual conditions only on one
side of unswitch and not another.
More precisely only these derivations hold true:
(Cond1 || Cond2) == false => Cond1 == Cond2 == false
(Cond1 && Cond2) == true => Cond1 == Cond2 == true
By the way we organize unswitching it means only replacing on "continue" blocks
and never on "unswitched" ones. Since trivial unswitch does not have "unswitched"
blocks it does not have this problem.
Fixes PR 39568.
Reviewers: chandlerc, asbirlea
Differential Revision: https://reviews.llvm.org/D54211
llvm-svn: 346350
If we simplify an instruction to itself, we do not need to add a user to
itself. For congruence classes with a defining expression, we already
use a similar logic.
Fixes PR38259.
Reviewers: davide, efriedma, mcrosier
Reviewed By: davide
Differential Revision: https://reviews.llvm.org/D51168
llvm-svn: 346335
This adds the llvm-side support for post-inlining evaluation of the
__builtin_constant_p GCC intrinsic.
Also fixed SCCPSolver::visitCallSite to not blow up when seeing a call
to a function where canConstantFoldTo returns true, and one of the
arguments is a struct.
Updated from patch initially by Janusz Sobczak.
Differential Revision: https://reviews.llvm.org/D4276
llvm-svn: 346322
LICM relies on variable `MustExecute` which is conservatively set to `false`
in all non-headers. It is used when we decide whether or not we want to hoist
an instruction or a guard.
For the guards, it might be too conservative to use this variable, we can
instead use a more precise logic from LoopSafetyInfo. Currently it is only NFC
because `IsMemoryNotModified` is also conservatively set to `false` for all
non-headers, and we cannot hoist guards from non-header blocks. However once we
give up using `IsMemoryNotModified` and use a smarter check instead, this will
allow us to hoist guards from all mustexecute non-header blocks.
Differential Revision: https://reviews.llvm.org/D50888
Reveiwed By: fedor.sergeev
llvm-svn: 346204
This patch makes LICM use `ICFLoopSafetyInfo` that is a smarter version
of LoopSafetyInfo that leverages power of Implicit Control Flow Tracking
to keep track of throwing instructions and give less pessimistic answers
to queries related to throws.
The ICFLoopSafetyInfo itself has been introduced in rL344601. This patch
enables it in LICM only.
Differential Revision: https://reviews.llvm.org/D50377
Reviewed By: apilipenko
llvm-svn: 346201
This reverts commit 2f425e9c7946b9d74e64ebbfa33c1caa36914402.
It seems that the check that we still should do the transform if we
know the result is constant is missing in this code. So the logic that
has been deleted by this change is still sometimes accidentally useful.
I revert the change to see what can be done about it. The motivating
case is the following:
@Y = global [400 x i16] zeroinitializer, align 1
define i16 @foo() {
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%i = phi i16 [ 0, %entry ], [ %inc, %for.body ]
%arrayidx = getelementptr inbounds [400 x i16], [400 x i16]* @Y, i16 0, i16 %i
store i16 0, i16* %arrayidx, align 1
%inc = add nuw nsw i16 %i, 1
%cmp = icmp ult i16 %inc, 400
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.body
%inc.lcssa = phi i16 [ %inc, %for.body ]
ret i16 %inc.lcssa
}
We should be able to figure out that the result is constant, but the patch
breaks it.
Differential Revision: https://reviews.llvm.org/D51584
llvm-svn: 346198
Summary:
This patch prevents MergeICmps to performn the transformation if the address operand GEP of the load instruction has a use outside of the load's parent block. Without this patch, compiler crashes with the given test case because the use of `%first.i` is still around when the basic block is erased from https://github.com/llvm-mirror/llvm/blob/master/lib/Transforms/Scalar/MergeICmps.cpp#L620. I think checking `isUsedOutsideOfBlock` with `GEP` is the original intention of the code, as the checking for `LoadI` is already performed in the same function.
This patch is incomplete though, as this makes the pass overly conservative and fails the test `tuple-four-int8.ll`. I believe what needs to be done is checking if GEP has a use outside of block that is not the part of "Comparisons" chain. Submit the patch as of now to prevent compiler crash.
Reviewers: courbet, trentxintong
Reviewed By: courbet
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D54089
llvm-svn: 346151
Summary:
-mldst-motion creates a new phi node without any debug info. Use the merged debug location from the incoming stores to fix this.
Fixes PR38177. The test case here is (somewhat) simplified from:
```
struct S {
int foo;
void fn(int bar);
};
void S::fn(int bar) {
if (bar)
foo = 1;
else
foo = 0;
}
```
Reviewers: dblaikie, gbedwell, aprantl, vsk
Reviewed By: vsk
Subscribers: vsk, JDevlieghere, llvm-commits
Tags: #debug-info
Differential Revision: https://reviews.llvm.org/D54019
llvm-svn: 346027
This patch factors out a function that makes all required updates
whenever an instruction gets erased.
Differential Revision: https://reviews.llvm.org/D54011
Reviewed By: apilipenko
llvm-svn: 345914
Inner-loop only reductions require additional checks to make sure they
form a load-phi-store cycle across inner and outer loop. Otherwise the
reduction value is not properly preserved. This patch disables
interchanging such loops for now, as it causes miscompiles in some
cases and it seems to apply only for a tiny amount of loops. Across the
test-suite, SPEC2000 and SPEC2006, 61 instead of 62 loops are
interchange with inner loop reduction support disabled. With
-loop-interchange-threshold=-1000, 3256 instead of 3267.
See the discussion and history of D53027 for an outline of how such legality
checks could look like.
Reviewers: efriedma, mcrosier, davide
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D53027
llvm-svn: 345877
When rewriting loop exit values, IndVars considers this transform not profitable if
the loop instruction has a loop user which it believes cannot be optimized away.
In current implementation only calls that immediately use the instruction are considered
as such.
This patch extends the definition of "hard" users to any side-effecting instructions
(which usually cannot be optimized away from the loop) and also allows handling
of not just immediate users, but use chains.
Differentlai Revision: https://reviews.llvm.org/D51584
Reviewed By: etherzhhb
llvm-svn: 345814
Unlike its legacy counterpart new pass manager's LoopUnrollPass does
not provide any means to select which flavors of unroll to run
(runtime, peeling, partial), relying on global defaults.
In some cases having ability to run a restricted LoopUnroll that
does more than LoopFullUnroll is needed.
Introduced LoopUnrollOptions to select optional unroll behaviors.
Added 'unroll<peeling>' to PassRegistry mainly for the sake of testing.
Reviewers: chandlerc, tejohnson
Differential Revision: https://reviews.llvm.org/D53440
llvm-svn: 345723
For some unclear reason rewriteLoopExitValues considers recalculation
after the loop profitable if it has some "soft uses" outside the loop (i.e. any
use other than call and return), even if we have proved that it has a user inside
the loop which we think will not be optimized away.
There is no existing unit test that would explain this. This patch provides an
example when rematerialisation of exit value is not profitable but it passes
this check due to presence of a "soft use" outside the loop.
It makes no sense to recalculate value on exit if we are going to compute it
due to some irremovable within the loop. This patch disallows applying this
transform in the described situation.
Differential Revision: https://reviews.llvm.org/D51581
Reviewed By: etherzhhb
llvm-svn: 345708
This fixes an assertion when constant folding a GEP when the part of the offset
was in i32 (IndexSize, as per DataLayout) and part in the i64 (PointerSize) in
the newly created test case.
Differential Revision: https://reviews.llvm.org/D52609
llvm-svn: 345585
Summary:
The visitICmp analysis function would record compares of pointer types, as size 0. This causes the resulting memcmp() call to have the wrong total size.
Found with "self-build" of clang/LLVM on Windows.
Reviewers: christylee, trentxintong, courbet
Reviewed By: courbet
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D53536
llvm-svn: 345413
This patch adds support of `llvm.experimental.guard` intrinsics to non-trivial
simple loop unswitching. These intrinsics represent implicit control flow which
has pretty much the same semantics as usual conditional branches. The
algorithm of dealing with them is following:
- Consider guards as unswitching candidates;
- If a guard is considered the best candidate, turn it into a branch;
- Apply normal unswitching algorithm on this branch.
The patch has no compile time effect on code that does not contain any guards.
Differential Revision: https://reviews.llvm.org/D53744
Reviewed By: chandlerc
llvm-svn: 345387
We should be able to make all relevant checks before we actually start the non-trivial
unswitching, so that we could guarantee that once we have started the transform,
it will always succeed.
Reviewed By: chandlerc
Differential Revision: https://reviews.llvm.org/D53747
llvm-svn: 345375
This work is to avoid regressions when we seperate FNeg from the FSub IR instruction.
Differential Revision: https://reviews.llvm.org/D53205
llvm-svn: 345146
LSR reassociates constants as unfolded offsets when the constants fit as
immediate add operands, which currently prevents such constants from being
combined later with loop invariant registers.
This patch modifies GenerateCombinations() to generate a second formula which
includes the unfolded offset in the combined loop-invariant register.
Differential Revision: https://reviews.llvm.org/D51861
llvm-svn: 345114
We need to update this code before introducing an 'fneg' instruction in IR,
so we might as well kill off the integer neg/not queries too.
This is no-functional-change-intended for scalar code and most vector code.
For vectors, we can see that the 'match' API allows for undef elements in
constants, so we optimize those cases better.
Ideally, there would be a test for each code diff, but I don't see evidence
of that for the existing code, so I didn't try very hard to come up with new
vector tests for each code change.
Differential Revision: https://reviews.llvm.org/D53533
llvm-svn: 345042
This pass could probably be modified slightly to allow
vector splat transforms for practically no cost, but
it only works on scalars for now. So the use of the
newer 'match' API should make no functional difference.
llvm-svn: 345030
This removes the primary remaining API producing `TerminatorInst` which
will reduce the rate at which code is introduced trying to use it and
generally make it much easier to remove the remaining APIs across the
codebase.
Also clean up some of the stragglers that the previous mechanical update
of variables missed.
Users of LLVM and out-of-tree code generally will need to update any
explicit variable types to handle this. Replacing `TerminatorInst` with
`Instruction` (or `auto`) almost always works. Most of these edits were
made in prior commits using the perl one-liner:
```
perl -i -ple 's/TerminatorInst(\b.* = .*getTerminator\(\))/Instruction\1/g'
```
This also my break some rare use cases where people overload for both
`Instruction` and `TerminatorInst`, but these should be easily fixed by
removing the `TerminatorInst` overload.
llvm-svn: 344504
are terminators without relying on the specific `TerminatorInst` type.
This required cleaning up two users of `InstVisitor`s usage of
`TerminatorInst` as well.
llvm-svn: 344503
by `getTerminator()` calls instead be declared as `Instruction`.
This is the biggest remaining chunk of the usage of `getTerminator()`
that insists on the narrow type and so is an easy batch of updates.
Several files saw more extensive updates where this would cascade to
requiring API updates within the file to use `Instruction` instead of
`TerminatorInst`. All of these were trivial in nature (pervasively using
`Instruction` instead just worked).
llvm-svn: 344502
This is the last interesting usage in all of LLVM's headers. The
remaining usages in headers are the core typesystem bits (Core.h,
instruction types, and InstVisitor) and as the return of
`BasicBlock::getTerminator`. The latter is the big remaining API point
that I'll remove after mass updates to user code.
llvm-svn: 344501
This requires updating a number of .cpp files to adapt to the new API.
I've just systematically updated all uses of `TerminatorInst` within
these files te `Instruction` so thta I won't have to touch them again in
the future.
llvm-svn: 344498
Moving away from UnknownSize is part of the effort to migrate us to
LocationSizes (e.g. the cleanup promised in D44748).
This doesn't entirely remove all of the uses of UnknownSize; some uses
require tweaks to assume that UnknownSize isn't just some kind of int.
This patch is intended to just be a trivial replacement for all places
where LocationSize::unknown() will Just Work.
llvm-svn: 344186
I've added a new test case that causes the scalarizer to try and use
dead-and-erased values - caused by the basic blocks not being in
domination order within the function. To fix this, instead of iterating
through the blocks in function order, I walk them in reverse post order.
Differential Revision: https://reviews.llvm.org/D52540
llvm-svn: 344128
There are places where we need to merge multiple LocationSizes of
different sizes into one, and get a sensible result.
There are other places where we want to optimize aggressively based on
the value of a LocationSizes (e.g. how can a store of four bytes be to
an area of storage that's only two bytes large?)
This patch makes LocationSize hold an 'imprecise' bit to note whether
the LocationSize can be treated as an upper-bound and lower-bound for
the size of a location, or just an upper-bound.
This concludes the series of patches leading up to this. The most recent
of which is r344108.
Fixes PR36228.
Differential Revision: https://reviews.llvm.org/D44748
llvm-svn: 344114
This is the second in a series of changes intended to make
https://reviews.llvm.org/D44748 more easily reviewable. Please see that
patch for more context. The first change being r344012.
Since I was requested to do all of this with post-commit review, this is
about as small as I can make this patch.
This patch makes LocationSize into an actual type that wraps a uint64_t;
users are required to call getValue() in order to get the size now. If
the LocationSize has an Unknown size (e.g. if LocSize ==
MemoryLocation::UnknownSize), getValue() will assert.
This also adds DenseMap specializations for LocationInfo, which required
taking two more values from the set of values LocationInfo can
represent. Hence, heavy users of multi-exabyte arrays or structs may
observe slightly lower-quality code as a result of this change.
The intent is for getValue()s to be very close to a corresponding
hasValue() (which is often spelled `!= MemoryLocation::UnknownSize`).
Sadly, small diff context appears to crop that out sometimes, and the
last change in DSE does require a bit of nonlocal reasoning about
control-flow. :/
This also removes an assert, since it's now redundant with the assert in
getValue().
llvm-svn: 344013
This is one of a series of changes intended to make
https://reviews.llvm.org/D44748 more easily reviewable. Please see that
patch for more context.
Since I was requested to do all of this with post-commit review, this is
about as small as I can make it (beyond committing changes to these few
files separately, but they're incredibly similar in spirit, so...)
On its own, this change doesn't make a great deal of sense. I plan on
having a follow-up Real Soon Now(TM) to make the bits here make more
sense. :)
In particular, the next change in this series is meant to make
LocationSize an actual type, which you have to call .getValue() on in
order to get at the uint64_t inside. Hence, this change refactors code
so that:
- we only need to call the soon-to-come getValue() once in most cases,
and
- said call to getValue() happens very closely to a piece of code that
checks if the LocationSize has a value (e.g. if it's != UnknownSize).
llvm-svn: 344012
In r339636 the alias analysis rules were changed with regards to tail calls
and byval arguments. Previously, tail calls were assumed not to alias
allocas from the current frame. This has been updated, to not assume this
for arguments with the byval attribute.
This patch aligns TailCallElim with the new rule. Tail marking can now be
more aggressive and mark more calls as tails, e.g.:
define void @test() {
%f = alloca %struct.foo
call void @bar(%struct.foo* byval %f)
ret void
}
define void @test2(%struct.foo* byval %f) {
call void @bar(%struct.foo* byval %f)
ret void
}
define void @test3(%struct.foo* byval %f) {
%agg.tmp = alloca %struct.foo
%0 = bitcast %struct.foo* %agg.tmp to i8*
%1 = bitcast %struct.foo* %f to i8*
call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %1, i64 40, i1 false)
call void @bar(%struct.foo* byval %agg.tmp)
ret void
}
The problematic case where a byval parameter is captured by a call is still
handled correctly, and will not be marked as a tail (see PR7272).
llvm-svn: 343986
This patch turns LoopInterchange into a loop pass. It now only
considers top-level loops and tries to move the innermost loop to the
optimal position within the loop nest. By only looking at top-level
loops, we might miss a few opportunities the function pass would get
(e.g. if we have a loop nest of 3 loops, in the function pass
we might process loops at level 1 and 2 and move the inner most loop to
level 1, and then we process loops at levels 0, 1, 2 and interchange
again, because we now have a different inner loop). But I think it would
be better to handle such cases by picking the best inner loop from the
start and avoid re-visiting the same loops again.
The biggest advantage of it being a function pass is that it interacts
nicely with the other loop passes. Without this patch, there are some
performance regressions on AArch64 with loop interchanging enabled,
where no loops were interchanged, but we missed out on some other loop
optimizations.
It also removes the SimplifyCFG run. We are just changing branches, so
the CFG should not be more complicated, besides the additional 'unique'
preheaders this pass might create.
Reviewers: chandlerc, efriedma, mcrosier, javed.absar, xbolva00
Reviewed By: xbolva00
Differential Revision: https://reviews.llvm.org/D51702
llvm-svn: 343308
This patch extends LoopInterchange to move LCSSA to the right place
after interchanging. This is required for LoopInterchange to become a
function pass.
An alternative to the manual moving of the PHIs, we could also re-form
the LCSSA phis for a set of interchanged loops, but that's more
expensive.
Reviewers: efriedma, mcrosier, davide
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D52154
llvm-svn: 343132
This reverts commit bd7b44f35ee9fbe365eb25ce55437ea793b39346.
Reland r342994: disabled the optimization and explicitly enable it in test.
-mllvm -consthoist-min-num-to-rebase<unsigned>=0
[ConstHoist] Do not rebase single (or few) dependent constant
If an instance (InsertionPoint or IP) of Base constant A has only one or few
rebased constants depending on it, do NOT rebase. One extra ADD instruction is
required to materialize each rebased constant, assuming A and the rebased have
the same materialization cost.
Differential Revision: https://reviews.llvm.org/D52243
llvm-svn: 343053
If an instance (InsertionPoint or IP) of Base constant A has only one or few
rebased constants depending on it, do NOT rebase. One extra ADD instruction is
required to materialize each rebased constant, assuming A and the rebased have
the same materialization cost.
Differential Revision: https://reviews.llvm.org/D52243
llvm-svn: 342994
Summary:
The default target of the switch instruction may sometimes be an
"unreachable" block, when it is guaranteed that one of the cases is
always taken. The dominator tree concludes that such a switch
instruction does not have an immediate post dominator. This confuses
divergence analysis, which is unable to propagate sync dependence to
the targets of the switch instruction.
As a workaround, the AMDGPU target now invokes lower-switch as a
preISel pass. LowerSwitch is designed to handle the unreachable
default target correctly, allowing the divergence analysis to locate
the correct immediate dominator of the now-lowered switch.
Reviewers: arsenm, nhaehnle
Reviewed By: nhaehnle
Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, llvm-commits, simoll
Differential Revision: https://reviews.llvm.org/D52221
llvm-svn: 342722
Summary:
his code was in CGDecl.cpp and really belongs in LLVM's isBytewiseValue. Teach isBytewiseValue the tricks clang's isRepeatedBytePattern had, including merging undef properly, and recursing on more types.
clang part of this patch: D51752
Subscribers: dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D51751
llvm-svn: 342709
Pass Execution Instrumentation interface enables customizable instrumentation
of pass execution, as per "RFC: Pass Execution Instrumentation interface"
posted 06/07/2018 on llvm-dev@
The intent is to provide a common machinery to implement all
the pass-execution-debugging features like print-before/after,
opt-bisect, time-passes etc.
Here we get a basic implementation consisting of:
* PassInstrumentationCallbacks class that handles registration of callbacks
and access to them.
* PassInstrumentation class that handles instrumentation-point interfaces
that call into PassInstrumentationCallbacks.
* Callbacks accept StringRef which is just a name of the Pass right now.
There were some ideas to pass an opaque wrapper for the pointer to pass instance,
however it appears that pointer does not actually identify the instance
(adaptors and managers might have the same address with the pass they govern).
Hence it was decided to go simple for now and then later decide on what the proper
mental model of identifying a "pass in a phase of pipeline" is.
* Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies
on different IRUnits (e.g. Analyses).
* PassInstrumentationAnalysis analysis is explicitly requested from PassManager through
usual AnalysisManager::getResult. All pass managers were updated to run that
to get PassInstrumentation object for instrumentation calls.
* Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra
args out of a generic PassManager's extra args. This is the only way I was able to explicitly
run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or
RepeatedPass::run.
TODO: Upon lengthy discussions we agreed to accept this as an initial implementation
and then get rid of getAnalysisResult by improving RepeatedPass implementation.
* PassBuilder takes PassInstrumentationCallbacks object to pass it further into
PassInstrumentationAnalysis. Callbacks registration should be performed directly
through PassInstrumentationCallbacks.
* new-pm tests updated to account for PassInstrumentationAnalysis being run
* Added PassInstrumentation tests to PassBuilderCallbacks unit tests.
Other unit tests updated with registration of the now-required PassInstrumentationAnalysis.
Made getName helper to return std::string (instead of StringRef initially) to fix
asan builtbot failures on CGSCC tests.
Reviewers: chandlerc, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D47858
llvm-svn: 342664
Summary:
Before removing basic blocks that ipsccp has considered as dead
all uses of the basic block label must be removed. That is done
by calling ConstantFoldTerminator on the users. An exception
is when the branch condition is an undef value. In such
scenarios ipsccp is using some internal assumptions regarding
which edge in the control flow that should remain, while
ConstantFoldTerminator don't know how to fold the terminator.
The problem addressed here is related to ConstantFoldTerminator's
ability to rewrite a 'switch' into a conditional 'br'. In such
situations ConstantFoldTerminator returns true indicating that
the terminator has been rewritten. However, ipsccp treated the
true value as if the edge to the dead basic block had been
removed. So the code for resolving an undef branch condition
did not trigger, and we ended up with assertion that there were
uses remaining when deleting the basic block.
The solution is to resolve indeterminate branches before the
call to ConstantFoldTerminator.
Reviewers: efriedma, fhahn, davide
Reviewed By: fhahn
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52232
llvm-svn: 342632
Pass Execution Instrumentation interface enables customizable instrumentation
of pass execution, as per "RFC: Pass Execution Instrumentation interface"
posted 06/07/2018 on llvm-dev@
The intent is to provide a common machinery to implement all
the pass-execution-debugging features like print-before/after,
opt-bisect, time-passes etc.
Here we get a basic implementation consisting of:
* PassInstrumentationCallbacks class that handles registration of callbacks
and access to them.
* PassInstrumentation class that handles instrumentation-point interfaces
that call into PassInstrumentationCallbacks.
* Callbacks accept StringRef which is just a name of the Pass right now.
There were some ideas to pass an opaque wrapper for the pointer to pass instance,
however it appears that pointer does not actually identify the instance
(adaptors and managers might have the same address with the pass they govern).
Hence it was decided to go simple for now and then later decide on what the proper
mental model of identifying a "pass in a phase of pipeline" is.
* Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies
on different IRUnits (e.g. Analyses).
* PassInstrumentationAnalysis analysis is explicitly requested from PassManager through
usual AnalysisManager::getResult. All pass managers were updated to run that
to get PassInstrumentation object for instrumentation calls.
* Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra
args out of a generic PassManager's extra args. This is the only way I was able to explicitly
run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or
RepeatedPass::run.
TODO: Upon lengthy discussions we agreed to accept this as an initial implementation
and then get rid of getAnalysisResult by improving RepeatedPass implementation.
* PassBuilder takes PassInstrumentationCallbacks object to pass it further into
PassInstrumentationAnalysis. Callbacks registration should be performed directly
through PassInstrumentationCallbacks.
* new-pm tests updated to account for PassInstrumentationAnalysis being run
* Added PassInstrumentation tests to PassBuilderCallbacks unit tests.
Other unit tests updated with registration of the now-required PassInstrumentationAnalysis.
Reviewers: chandlerc, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D47858
llvm-svn: 342597
Summary:
Pass Execution Instrumentation interface enables customizable instrumentation
of pass execution, as per "RFC: Pass Execution Instrumentation interface"
posted 06/07/2018 on llvm-dev@
The intent is to provide a common machinery to implement all
the pass-execution-debugging features like print-before/after,
opt-bisect, time-passes etc.
Here we get a basic implementation consisting of:
* PassInstrumentationCallbacks class that handles registration of callbacks
and access to them.
* PassInstrumentation class that handles instrumentation-point interfaces
that call into PassInstrumentationCallbacks.
* Callbacks accept StringRef which is just a name of the Pass right now.
There were some ideas to pass an opaque wrapper for the pointer to pass instance,
however it appears that pointer does not actually identify the instance
(adaptors and managers might have the same address with the pass they govern).
Hence it was decided to go simple for now and then later decide on what the proper
mental model of identifying a "pass in a phase of pipeline" is.
* Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies
on different IRUnits (e.g. Analyses).
* PassInstrumentationAnalysis analysis is explicitly requested from PassManager through
usual AnalysisManager::getResult. All pass managers were updated to run that
to get PassInstrumentation object for instrumentation calls.
* Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra
args out of a generic PassManager's extra args. This is the only way I was able to explicitly
run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or
RepeatedPass::run.
TODO: Upon lengthy discussions we agreed to accept this as an initial implementation
and then get rid of getAnalysisResult by improving RepeatedPass implementation.
* PassBuilder takes PassInstrumentationCallbacks object to pass it further into
PassInstrumentationAnalysis. Callbacks registration should be performed directly
through PassInstrumentationCallbacks.
* new-pm tests updated to account for PassInstrumentationAnalysis being run
* Added PassInstrumentation tests to PassBuilderCallbacks unit tests.
Other unit tests updated with registration of the now-required PassInstrumentationAnalysis.
Reviewers: chandlerc, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D47858
llvm-svn: 342544
Summary:
Adds LLVMAddUnifyFunctionExitNodesPass to expose
createUnifyFunctionExitNodesPass to the C and OCaml APIs.
Reviewers: whitequark, deadalnix
Reviewed By: whitequark
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52212
llvm-svn: 342476
A piece of logic in rewriteLoopExitValues has a weird check on number of
users which allowed an unprofitable transform in case if an instruction has
more than 6 users.
Differential Revision: https://reviews.llvm.org/D51404
Reviewed By: etherzhhb
llvm-svn: 342444
Summary:
EarlyCSE can make IR changes that will leave MemorySSA with accesses claiming to be optimized, but for which a subsequent MemorySSA run will yield a different optimized result.
Due to relying on AA queries, we can't fix this in general, unless we recompute MemorySSA.
Adding some tests to track this and a basic verify for future potential failures.
Reviewers: george.burgess.iv, gberry
Subscribers: sanjoy, jlebar, Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D51960
llvm-svn: 342422
As preparation for LoopInterchange becoming a loop pass, it needs to
preserve ScalarEvolution. Even though interchanging should not change
the trip count of the loop, it modifies loop entry, latch and exit
blocks.
I added -verify-scev to some loop interchange tests, but the verification does
not catch problems caused by missing invalidation of SE in loop interchange, as
the trip counts themselves do not change. So there might be potential to
make the SE verification covering more stuff in the future.
Reviewers: mkazantsev, efriedma, karthikthecool
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D52026
llvm-svn: 342209
This adds DebugCounter support to the PartiallyInlineLibCalls pass,
which should make debugging/automated bisection easier in the future.
Patch by Zhizhou Yang!
Differential Revision: https://reviews.llvm.org/D50093
llvm-svn: 342172
Fix for https://bugs.llvm.org/show_bug.cgi?id=38912.
In GVNHoist::computeInsertionPoints() we iterate over the Value
Numbers and calculate the Iterated Dominance Frontiers without
clearing the IDFBlocks vector first. IDFBlocks ends up accumulating
an insane number of basic blocks, which bloats the compilation time
of SemaChecking.cpp with ubsan enabled.
Differential Revision: https://reviews.llvm.org/D51980
llvm-svn: 342055
Summary:
Update MemorySSA in old LoopUnswitch pass.
Actual dependency and update is disabled by default.
Subscribers: sanjoy, jlebar, Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D45301
llvm-svn: 341984
There are 2 cases when we create PHI nodes:
* For the result of the call that was duplicated in the split blocks.
Those PHI nodes should have the debug location of the call.
* For values produced before the call. Those instructions need to be
duplicated in the split blocks and the PHI nodes should have the
debug locations of those instructions.
Fixes PR37962.
Reviewers: junbuml, gbedwell, vsk
Reviewed By: junbuml
Tags: #debug-info
Differential Revision: https://reviews.llvm.org/D51919
llvm-svn: 341970
Currently we re-use cached info from sub loops or traverse them
to populate AliasSetTracker. But after that we traverse all basic blocks
from the current loop. This is redundant work.
All what we need is traversing the all basic blocks from the loop except
those which are used to get the data from the cache.
This should improve compile time only.
Reviewers: mkazantsev, reames, kariddi, anna
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D51715
llvm-svn: 341896
IndVarSimplify's design is somewhat odd in the way how it reports that
some transform has made a change. It has a `Changed` field which can
be set from within any function, which makes it hard to track whether or
not it was set properly after a transform was made. It leads to oversights
in setting this flag where needed, see example in PR38855.
This patch removes the `Changed` field, turns it into a local and unifies
the signatures of all relevant transform functions to return boolean value
which designates whether or not this transform has made a change.
Differential Revision: https://reviews.llvm.org/D51850
Reviewed By: skatkov
llvm-svn: 341893
I'd made exactly this same change before, but it appears to have been accidentally reverted in another change. (I'm assuming accidental since it was without comment or test case, and in an unrelated change.)
llvm-svn: 341892
When GVN propagates an equality by replacing one value with another it also
needs to invalidate the cached information for the value being replaced.
Differential Revision: https://reviews.llvm.org/D51218
llvm-svn: 341820
Currently, `rewriteFirstIterationLoopExitValues` does not set Changed flag even if it makes
changes in the IR. There is no clear evidence that it can cause a crash, but it
looks highly suspicious and likely invalid.
Differential Revision: https://reviews.llvm.org/D51779
Reviewed By: skatkov
llvm-svn: 341779
Currently, `sinkUnusedInvariants` does not set Changed flag even if it makes
changes in the IR. There is no clear evidence that it can cause a crash, but it
looks highly suspicious and likely invalid.
Differential Revision: https://reviews.llvm.org/D51777
Reviewed By: skatkov
llvm-svn: 341777
Currently eliminateInstructions only returns true if any instruction got
replaced. In the test case for this patch, we eliminate the trivially
dead calls, for which eliminateInstructions not do a replacement and the
function is not marked as changed, which is why the inliner crashes
while traversing the call graph.
Alternatively we could also change eliminateInstructions to return true
in case we mark instructions for deletion, but that's slightly more code
and doing it at the place where the replacement happens seems safer.
Fixes PR37517.
Reviewers: davide, mcrosier, efriedma, bjope
Reviewed By: bjope
Differential Revision: https://reviews.llvm.org/D51169
llvm-svn: 341651
IndVars does not set `Changed` flag when it eliminates dead instructions. As result,
it may make IR modifications and report that it has done nothing. It leads to inconsistent
preserved analyzes results.
Differential Revision: https://reviews.llvm.org/D51770
Reviewed By: skatkov
llvm-svn: 341633
There is no need to create preheaders in the analysis stage, we only
need them when adjusting the branches. Also, the only cases we need to
create our own preheaders is when they have more than 1 predecessors or
PHI nodes (even with only 1 predecessor, we could have an LCSSA phi
node). I have simplified the conditions and added some assertions to be
sure. Because we know the inner and outer loop need to be tightly
nested, it is sufficient to check if the inner loop preheader is the
outer loop header to check if we need to create a new preheader.
Reviewers: efriedma, mcrosier, karthikthecool
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D51703
llvm-svn: 341533
Function rewriteLoopExitValues contains a check on isValidRewrite which
is needed to make sure that SCEV does not convert the pattern
`gep Base, (&p[n] - &p[0])` into `gep &p[n], Base - &p[0]`. This problem
has been fixed in SCEV long ago, so this check is just obsolete.
This patch converts it into an assertion to make sure that the SCEV will
not mess up this case in the future.
Differential Revision: https://reviews.llvm.org/D51582
Reviewed By: atrick
llvm-svn: 341516
Reland r341269. Use std::stable_sort when sorting constant condidates.
Reverting commit, r341365:
Revert r341269: [Constant Hoisting] Hoisting Constant GEP Expressions
One of the tests is failing 50% of the time when expensive checks are
enabled. Not sure how deep the problem is so just reverting while the
author can investigate so that the bots stop repeatedly failing and
blaming things incorrectly. Will respond with details on the original
commit.
Original commit, r341269:
[Constant Hoisting] Hoisting Constant GEP Expressions
Leverage existing logic in constant hoisting pass to transform constant GEP
expressions sharing the same base global variable. Multi-dimensional GEPs are
rewritten into single-dimensional GEPs.
https://reviews.llvm.org/D51396
Differential Revision: https://reviews.llvm.org/D51654
llvm-svn: 341417
Recent change to deleteDeadBlocksFromLoop was not enough to
fix all the problems related to dead blocks after nontrivial
unswitching of switches.
We need to delete all the dead blocks that were created during
unswitching, otherwise we will keep having problems with phi's
or dead blocks.
This change removes all the dead blocks that are reachable from the loop,
not trying to track whether these blocks are newly created by unswitching
or not. While not completely correct, we are unlikely to get loose but
reachable dead blocks that do not belong to our loop nest.
It does fix all the failures currently known, in particular PR38778.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D51519
llvm-svn: 341398
One of the tests is failing 50% of the time when expensive checks are
enabled. Not sure how deep the problem is so just reverting while the
author can investigate so that the bots stop repeatedly failing and
blaming things incorrectly. Will respond with details on the original
commit.
llvm-svn: 341365
This patch removes the function `expandSCEVIfNeeded` which behaves not as
it was intended. This function tries to make a lookup for exact existing expansion
and only goes to normal expansion via `expandCodeFor` if this lookup hasn't found
anything. As a result of this, if some instruction above the loop has a `SCEVConstant`
SCEV, this logic will return this instruction when asked for this `SCEVConstant` rather
than return a constant value. This is both non-profitable and in some cases leads to
breach of LCSSA form (as in PR38674).
Whether or not it is possible to break LCSSA with this algorithm and with some
non-constant SCEVs is still in question, this is still being investigated. I wasn't
able to construct such a test so far, so maybe this situation is impossible. If it is,
it will go as a separate fix.
Rather than do it, it is always correct to just invoke `expandCodeFor` unconditionally:
it behaves smarter about insertion points, and as side effect of this it will choose a
constant value for SCEVConstants. For other SCEVs it may end up finding a better insertion
point. So it should not be worse in any case.
NOTE: So far the only known case for which this transform may break LCSSA is mapping
of SCEVConstant to an instruction. However there is a suspicion that the entire algorithm
can compromise LCSSA form for other cases as well (yet not proved).
Differential Revision: https://reviews.llvm.org/D51286
Reviewed By: etherzhhb
llvm-svn: 341345
If we have a pair of binops feeding another pair of binops, rearrange the operands so
the matching pair are together because that allows easy factorization folds to happen
in instcombine:
((X << S) & Y) & (Z << S) --> ((X << S) & (Z << S)) & Y (reassociation)
--> ((X & Z) << S) & Y (factorize shift from 'and' ops optimization)
This is part of solving PR37098:
https://bugs.llvm.org/show_bug.cgi?id=37098
Note that there's an instcombine version of this patch attached there, but we're trying
to make instcombine have less responsibility to improve compile-time efficiency.
For reasons I still don't completely understand, reassociate does this kind of transform
sometimes, but misses everything in my motivating cases.
This patch on its own is gluing an independent cleanup chunk to the end of the existing
RewriteExprTree() loop. We can build on it and do something stronger to better order the
full expression tree like D40049. That might be an alternative to the proposal to add a
separate reassociation pass like D41574.
Differential Revision: https://reviews.llvm.org/D45842
llvm-svn: 341288
Leverage existing logic in constant hoisting pass to transform constant GEP
expressions sharing the same base global variable. Multi-dimensional GEPs are
rewritten into single-dimensional GEPs.
Differential Revision: https://reviews.llvm.org/D51396
llvm-svn: 341269
Splitting an alloca can decrease the alignment of GEPs into the
partition. Normally, rewriting accounts for this, but the code was
missing for uses of PHI nodes and select instructions.
Fixes https://bugs.llvm.org/show_bug.cgi?id=38707 .
Differential Revision: https://reviews.llvm.org/D51335
llvm-svn: 341094
Summary:
This is patch 1 of the new DivergenceAnalysis (https://reviews.llvm.org/D50433).
The purpose of this patch is to free up the name DivergenceAnalysis for the new generic
implementation. The generic implementation class will be shared by specialized
divergence analysis classes.
Patch by: Simon Moll
Reviewed By: nhaehnle
Subscribers: jvesely, jholewinski, arsenm, nhaehnle, mgorny, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D50434
Change-Id: Ie8146b11be2c50d5312f30e11c7a3036a15b48cb
llvm-svn: 341071
Joseph Tremoulet