While here move simplifyLoop() function to the new header, as
suggested by Chandler in the review.
Differential Revision: http://reviews.llvm.org/D21404
llvm-svn: 274959
SimplifyCFG had logic to insert calls to llvm.trap for two very
particular IR patterns: stores and invokes of undef/null.
While InstCombine canonicalizes certain undefined behavior IR patterns
to stores of undef, phase ordering means that this cannot be relied upon
in general.
There are much better tools than llvm.trap: UBSan and ASan.
N.B. I could be argued into reverting this change if a clear argument as
to why it is important that we synthesize llvm.trap for stores, I'd be
hard pressed to see why it'd be useful for invokes...
llvm-svn: 273778
r273711 was reverted by r273743. The inliner needs to know about any
call sites in the inlined function. These were obscured if we replaced
a call to undef with an undef but kept the call around.
This fixes PR28298.
llvm-svn: 273753
This patch moves MSSA's caching walker into MemorySSA, and moves the
actual definition of MSSA's caching walker out of MemorySSA.h. This is
done in preparation for the new walker, which should be out for review
soonish.
Also, this patch removes a field from UpwardsMemoryQuery and has a few
lines of diff from clang-format'ing MemorySSA.cpp.
llvm-svn: 273723
reduce the number of comparisons.
Specifically, InstCombine can turn:
(i == 5334 || i == 5335)
into:
((i | 1) == 5335)
SimplifyCFG was already able to detect the pattern:
(i == 5334 || i == 5335)
to:
((i & -2) == 5334)
This patch supersedes D21315 and resolves PR27555
(https://llvm.org/bugs/show_bug.cgi?id=27555).
Thanks to David and Chandler for the suggestions!
Author: Thomas Jablin (tjablin)
Reviewers: majnemer chandlerc halfdan cycheng
http://reviews.llvm.org/D21397
llvm-svn: 273639
CodeGen has hooks that allow targets to emit specialized code instead
of calls to memcmp, memchr, strcpy, stpcpy, strcmp, strlen, strnlen.
When ASan/MSan/TSan/ESan is in use, this sidesteps its interceptors, resulting
in uninstrumented memory accesses. To avoid that, make these sanitizers
mark the calls as nobuiltin.
Differential Revision: http://reviews.llvm.org/D19781
llvm-svn: 273083
Switch from m_Constant to m_APInt per David's request. NFC.
Author: Thomas Jablin (tjablin)
Reviewers: majnemer cycheng
http://reviews.llvm.org/D21440
llvm-svn: 272977
When moving unsafe allocas to the unsafe stack, dbg.declare intrinsics are
updated to refer to the new location.
This change does the same to dbg.value intrinsics.
llvm-svn: 272968
We should update results of the BranchProbabilityInfo after removing block in JumpThreading. Otherwise
we will get dangling pointer inside BranchProbabilityInfo cache.
Differential Revision: http://reviews.llvm.org/D20957
llvm-svn: 272891
(i == 5334 || i == 5335)
to:
((i & -2) == 5334)
This transformation has some incorrect side conditions. Specifically, the
transformation is only applied when the right-hand side constant (5334 in
the example) is a power of two not equal and not equal to the negated mask.
These side conditions were added in r258904 to fix PR26323. The correct side
condition is that: ((Constant & Mask) == Constant)[(5334 & -2) == 5334].
It's a little bit hard to see why these transformations are correct and what
the side conditions ought to be. Here is a CVC3 program to verify them for
64-bit values:
ONE : BITVECTOR(64) = BVZEROEXTEND(0bin1, 63);
x : BITVECTOR(64);
y : BITVECTOR(64);
z : BITVECTOR(64);
mask : BITVECTOR(64) = BVSHL(ONE, z);
QUERY( (y & ~mask = y) =>
((x & ~mask = y) <=> (x = y OR x = (y | mask)))
);
Please note that each pattern must be a dual implication (<--> or iff). One
directional implication can create spurious matches. If the implication is
only one-way, an unsatisfiable condition on the left side can imply a
satisfiable condition on the right side. Dual implication ensures that
satisfiable conditions are transformed to other satisfiable conditions and
unsatisfiable conditions are transformed to other unsatisfiable conditions.
Here is a concrete example of a unsatisfiable condition on the left
implying a satisfiable condition on the right:
mask = (1 << z)
(x & ~mask) == y --> (x == y || x == (y | mask))
Substituting y = 3, z = 0 yields:
(x & -2) == 3 --> (x == 3 || x == 2)
The version of this code before r258904 had no side-conditions and
incorrectly justified itself in comments through one-directional
implication.
Thanks to Chandler for the suggestion!
Author: Thomas Jablin (tjablin)
Reviewers: chandlerc majnemer hfinkel cycheng
http://reviews.llvm.org/D21417
llvm-svn: 272873
If a local_unnamed_addr attribute is attached to a global, the address
is known to be insignificant within the module. It is distinct from the
existing unnamed_addr attribute in that it only describes a local property
of the module rather than a global property of the symbol.
This attribute is intended to be used by the code generator and LTO to allow
the linker to decide whether the global needs to be in the symbol table. It is
possible to exclude a global from the symbol table if three things are true:
- This attribute is present on every instance of the global (which means that
the normal rule that the global must have a unique address can be broken without
being observable by the program by performing comparisons against the global's
address)
- The global has linkonce_odr linkage (which means that each linkage unit must have
its own copy of the global if it requires one, and the copy in each linkage unit
must be the same)
- It is a constant or a function (which means that the program cannot observe that
the unique-address rule has been broken by writing to the global)
Although this attribute could in principle be computed from the module
contents, LTO clients (i.e. linkers) will normally need to be able to compute
this property as part of symbol resolution, and it would be inefficient to
materialize every module just to compute it.
See:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160509/356401.htmlhttp://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160516/356738.html
for earlier discussion.
Part of the fix for PR27553.
Differential Revision: http://reviews.llvm.org/D20348
llvm-svn: 272709
Ensuring that the PHI are all single-operand is not performed in the
second pass added by the previous pass. This removes the assert from
the first pass.
llvm-svn: 272650
We only used to add the edge from the cloned loop to PHIs that
corresponded to values defined by the loop. We need to do this for all
PHIs obviously since we need a PHI operand for each incoming edge.
This includes things like PHIs with a constant value or with values
defined before the original loop (see the testcases).
After the patch the PHIs are added to the exit block in two passes.
In the first pass we ensure there is a single-operand (LCSSA) PHI for
each value defined by the loop.
In the second pass we loop through each (single-operand) PHI and add the
value for the edge from the cloned loop. If the value is defined in the
loop we'll use the cloned instruction from the cloned loop.
Fixes PR28037
llvm-svn: 272649
This used to be free, copying and moving DebugLocs became expensive
after the metadata rewrite. Passing by reference eliminates a ton of
track/untrack operations. No functionality change intended.
llvm-svn: 272512
Summary:
Make isGuaranteedToExecute use the
isGuaranteedToTransferExecutionToSuccessor helper, and make that helper
a bit more accurate.
There's a potential performance impact here from assuming that arbitrary
calls might not return. This probably has little impact on loads and
stores to a pointer because most things alias analysis can reason about
are dereferenceable anyway. The other impacts, like less aggressive
hoisting of sdiv by a variable and less aggressive hoisting around
volatile memory operations, are unlikely to matter for real code.
This also impacts SCEV, which uses the same helper. It's a minor
improvement there because we can tell that, for example, memcpy always
returns normally. Strictly speaking, it's also introducing
a bug, but it's not any worse than everywhere else we assume readonly
functions terminate.
Fixes http://llvm.org/PR27857.
Reviewers: hfinkel, reames, chandlerc, sanjoy
Subscribers: broune, llvm-commits
Differential Revision: http://reviews.llvm.org/D21167
llvm-svn: 272489
Summary:
Dominator updation fails for a loop inserted with a new basicblock.
A block required by DT to set the IDom might not have been cloned yet. This is because there is no predefined ordering of loop blocks (except for the header block which should be the first block in the list).
The patch first creates DT nodes for the cloned blocks and then separately updates the DT in a follow-on loop.
Reviewers: anemet, dberlin
Subscribers: dberlin, llvm-commits
Differential Revision: http://reviews.llvm.org/D20899
llvm-svn: 272479
A memory access defined on function entry cannot be locally dominated by another memory access.
The patch was split from http://reviews.llvm.org/D19338 which exposes the problem.
Differential Revision: http://reviews.llvm.org/D21039
llvm-svn: 272436
Summary:
This fixes PR26682. Also add LCSSA as a preserved pass to LoopSimplify,
that looks correct to me and allows to write a test for the issue.
Reviewers: chandlerc, bogner, sanjoy
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D21112
llvm-svn: 272224
A basic block could contain:
%cp = cleanuppad []
cleanupret from %cp unwind to caller
This basic block is empty and is thus a candidate for removal. However,
there can be other uses of %cp outside of this basic block. This is
only possible in unreachable blocks.
Make our transform more correct by checking that the pad has a single
user before removing the BB.
This fixes PR28005.
llvm-svn: 271816
Add support for the new pass manager to MemorySSA pass.
Change MemorySSA to be computed eagerly upon construction.
Change MemorySSAWalker to be owned by the MemorySSA object that creates
it.
Reviewers: dberlin, george.burgess.iv
Subscribers: mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D19664
llvm-svn: 271432
This will be necessary to allow the global merge pass to attach
multiple debug info metadata nodes to global variables once we reverse
the edge from DIGlobalVariable to GlobalVariable.
Differential Revision: http://reviews.llvm.org/D20414
llvm-svn: 271358
Summary:
If we can prove that an op.with.overflow intrinsic does not overflow, we
can get rid of the intrinsic, and replace it with non-wrapping
arithmetic.
This was first checked in at r265913 but reverted in r265950 because it
exposed some issues around how SCEV handled post-inc add recurrences.
Those issues have now been fixed.
Reviewers: atrick, regehr
Subscribers: sanjoy, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D18685
llvm-svn: 271153
Summary:
When RF_NullMapMissingGlobalValues is set, mapValue can return null
for GlobalValue. When mapping the operands of a constant that is
referenced from metadata, we need to handle this case and actually
return null instead of mapping this constant.
Reviewers: dexonsmith, rafael
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D20713
llvm-svn: 271129
Summary:
Unroll factor (Count) calculations moved to a new function.
Early exits on pragma and "-unroll-count" defined factor added.
New type of unrolling "Force" introduced (previously used implicitly).
New unroll preference "AllowRemainder" introduced and set "true" by default.
(should be set to false for architectures that suffers from it).
Reviewers: hfinkel, mzolotukhin, zzheng
Differential Revision: http://reviews.llvm.org/D19553
From: Evgeny Stupachenko <evstupac@gmail.com>
llvm-svn: 271071
When we traced through a phi node looking for floating-point reductions, we
forgot whether we'd ever seen an instruction without fast-math flags (that
would block vectorization). This propagates it through to the end.
llvm-svn: 271015
If every operands of a constant are mapping to themselves, and the
type does not change, we have an early exit as acknowledged in the
comment:
// Otherwise, we have some other constant to remap. Start by checking to see
// if all operands have an identity remapping.
However instead of checking for identity the code was checking if the
operands were mapped to the constant itself, which is rarely true.
As a consequence, the coverage report showed that the early exit was
never taken.
llvm-svn: 270944
It turns out that too many passes are relying on alias analysis results
for control dependencies. Until we fix that by introducing a more accurate
modelling of control dependencies, special case assume in MemorySSA instead.
Also introduce tests to ensure we don't regress the FunctionAttrs or LICM
passes.
Differential Revision: http://reviews.llvm.org/D20658
llvm-svn: 270823
There is only one caller of MemorySSA::createNewAccess, and it passes true
as the IgnoreNonMemory argument. Remove that argument and fold its behavior
into createNewAccess.
llvm-svn: 270812
It may materialize a declaration, or a definition. The name could
be misleading. This is following a merge of materializeInitFor()
into materializeDeclFor().
Differential Revision: http://reviews.llvm.org/D20593
llvm-svn: 270759
They were originally separated to handle the co-recursion between
the ValueMapper and the ValueMaterializer. This recursion does not
exist anymore: the ValueMapper now uses a Worklist and the
ValueMaterializer is scheduling job on the Worklist.
Differential Revision: http://reviews.llvm.org/D20593
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 270758
Also, rename recognizeBitReverseOrBSwapIdiom to recognizeBSwapOrBitReverseIdiom,
so the ordering of the MatchBSwaps and MatchBitReversals arguments are
consistent with the function name.
llvm-svn: 270715
A cleanuppad is not cheap, they turn into many instructions and result
in additional spills and fills. It is not worth keeping a cleanuppad
around if all it does is hold a lifetime.end instruction.
N.B. We first try to merge the cleanuppad with another cleanuppad to
avoid dropping the lifetime and debug info markers.
llvm-svn: 270314
Summary: Set default branch weight to 1:1 if one of the branch has profile missing when simplifying CFG.
Reviewers: spatel, davidxl
Subscribers: danielcdh, llvm-commits
Differential Revision: http://reviews.llvm.org/D20307
llvm-svn: 269995
Ported DA to the new PM by splitting the former DependenceAnalysis Pass
into a DependenceInfo result type and DependenceAnalysisWrapperPass type
and adding a new PM-style DependenceAnalysis analysis pass returning the
DependenceInfo.
Patch by Philip Pfaffe, most of the review by Justin.
Differential Revision: http://reviews.llvm.org/D18834
llvm-svn: 269370
This new verifier rule lets us unambigously pick a calling convention
when creating a new declaration for
`@llvm.experimental.deoptimize.<ty>`. It is also congruent with our
lowering strategy -- since all calls to `@llvm.experimental.deoptimize`
are lowered to calls to `__llvm_deoptimize`, it is reasonable to enforce
a unique calling convention.
Some of the tests that were breaking this verifier rule have had to be
split up into different .ll files.
The inliner was violating this rule as well, and has been fixed to avoid
producing invalid IR.
llvm-svn: 269261
Summary: In sample profile, some branches may have profile missing due to profile inaccuracy. We want existing branch probability still valid after propagation.
Reviewers: hfinkel, davidxl, spatel
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D19948
llvm-svn: 269137
Remove the ModuleLevelChanges argument, and the ability to create new
subprograms for cloned functions. The latter was added without review in
r203662, but it has no in-tree clients (all non-test callers pass false
for ModuleLevelChanges [1], so it isn't reachable outside of tests). It
also isn't clear that adding a duplicate subprogram to the compile unit is
always the right thing to do when cloning a function within a module. If
this functionality comes back it should be accompanied with a more concrete
use case.
Furthermore, all in-tree clients add the returned function to the module.
Since that's pretty much the only sensible thing you can do with the function,
just do that in CloneFunction.
[1] http://llvm-cs.pcc.me.uk/lib/Transforms/Utils/CloneFunction.cpp/rCloneFunction
Differential Revision: http://reviews.llvm.org/D18628
llvm-svn: 269110
Allow vectorization when the step is a loop-invariant variable.
This is the loop example that is getting vectorized after the patch:
int int_inc;
int bar(int init, int *restrict A, int N) {
int x = init;
for (int i=0;i<N;i++){
A[i] = x;
x += int_inc;
}
return x;
}
"x" is an induction variable with *loop-invariant* step.
But it is not a primary induction. Primary induction variable with non-constant step is not handled yet.
Differential Revision: http://reviews.llvm.org/D19258
llvm-svn: 269023
Retrying r268550/r268751 which were reverted at r268577/r268765 due a memory sanitizer failure.
I have not been able to reproduce that failure, but I've taken another guess at fixing
the problem in this version of the patch and will watch for another failure.
Original commit message:
Unlike earlier similar fixes, we need to recalculate the branch weights
in this case.
Differential Revision: http://reviews.llvm.org/D19674
llvm-svn: 268767
Retrying r268550 which was reverted at r268577 due a memory sanitizer failure.
I have not been able to reproduce that failure, but I've taken a guess at fixing
the problem in this version of the patch and will watch for another failure.
Original commit message:
Unlike earlier similar fixes, we need to recalculate the branch weights
in this case.
Differential Revision: http://reviews.llvm.org/D19674
llvm-svn: 268751
This test was crashing, and currently it breaks bootstrapping clang with debuginfo
Differential Revision: http://reviews.llvm.org/D20008
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 268715
Summary: We need to clean up CFG before assigning discriminator to minimize the impact of optimization on debug info.
Reviewers: davidxl, dblaikie, dnovillo
Subscribers: dnovillo, danielcdh, llvm-commits
Differential Revision: http://reviews.llvm.org/D19926
llvm-svn: 268675
Summary:
Some PHIs can have expressions that are not AddRecExprs due to the presence
of sext/zext instructions. In order to prevent the Loop Vectorizer from
bailing out when encountering these PHIs, we now coerce the SCEV
expressions to AddRecExprs using SCEV predicates (when possible).
We only do this when the alternative would be to not vectorize.
Reviewers: mzolotukhin, anemet
Subscribers: mssimpso, sanjoy, mzolotukhin, llvm-commits
Differential Revision: http://reviews.llvm.org/D17153
llvm-svn: 268633
MemorySanitizer: use-of-uninitialized-value
0x4910e47 in count /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/include/llvm/Support/MathExtras.h:159:12
0x4910e47 in countLeadingZeros<unsigned long> /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/include/llvm/Support/MathExtras.h:183
0x4910e47 in FitWeights /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:855
0x4910e47 in SimplifyCondBranchToCondBranch /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:2895
This reverts commit 609f4dd4bf3bc735c8c047a4d4b0a8e9e4d202e2.
llvm-svn: 268577
Unlike earlier similar fixes, we need to recalculate the branch weights
in this case.
Differential Revision: http://reviews.llvm.org/D19674
llvm-svn: 268550
This patch fixes PR27615.
@llvm.dbg.value instructions no longer count towards the maximum number of
instructions to look back at in the instruction list when searching for a
store instruction. This should make the output consistent between debug and
non-debug build.
Patch by Henric Karlsson <henric.karlsson@ericsson.com>!
Differential Revision: http://reviews.llvm.org/D19912
llvm-svn: 268512
We forgot to consider the target of ifuncs when considering if a
function was alive or dead.
N.B. Also update a few auxiliary tools like bugpoint and
verify-uselistorder.
This fixes PR27593.
llvm-svn: 268468
Make it possible that TryToSimplifyUncondBranchFromEmptyBlock merges empty
basic block including lifetime intrinsics as well as phi nodes and
unconditional branch into its successor or predecessor(s).
If successor of empty block has single predecessor, all contents including
lifetime intrinsics are sinked into the successor. Otherwise, they are
hoisted into its predecessor(s) and then merged into the predecessor(s).
Patch by Josh Yoon <josh.yoon@samsung.com>!
Differential Revision: http://reviews.llvm.org/D19257
llvm-svn: 268254
This moves some logic added to EarlyCSE in rL268120 into
`llvm::isInstructionTriviallyDead`. Adds a test case for DCE to
demonstrate that passes other than EarlyCSE can now pick up on the new
information.
llvm-svn: 268126
This patch fixes two somewhat related bugs in MemorySSA's caching
walker. These bugs were found because D19695 brought up the problem
that we'd have defs cached to themselves, which is incorrect.
The bugs this fixes are:
- We would sometimes skip the nearest clobber of a MemoryAccess, because
we would query our cache for a given potential clobber before
checking if the potential clobber is the clobber we're looking for.
The cache entry for the potential clobber would point to the nearest
clobber *of the potential clobber*, so if that was a cache hit, we'd
ignore the potential clobber entirely.
- There are times (sometimes in DFS, sometimes in the getClobbering...
functions) where we would insert cache entries that say a def
clobbers itself.
There's a bit of common code between the fixes for the bugs, so they
aren't split out into multiple commits.
This patch also adds a few unit tests, and refactors existing tests a
bit to reduce the duplication of setup code.
llvm-svn: 268087
Summary:
Historically, we had a switch in the Makefiles for turning on "expensive
checks". This has never been ported to the cmake build, but the
(dead-ish) code is still around.
This will also make it easier to turn it on in buildbots.
Reviewers: chandlerc
Subscribers: jyknight, mzolotukhin, RKSimon, gberry, llvm-commits
Differential Revision: http://reviews.llvm.org/D19723
llvm-svn: 268050
When inlining a call site with llvm.mem.parallel_loop_access metadata, this
metadata needs to be propagated to all cloned memory-accessing instructions.
Otherwise, inlining parts of the loop body will invalidate the annotation.
With this functionality, we now vectorize the following as expected:
void Body(int *res, int *c, int *d, int *p, int i) {
res[i] = (p[i] == 0) ? res[i] : res[i] + d[i];
}
void Test(int *res, int *c, int *d, int *p, int n) {
int i;
#pragma clang loop vectorize(assume_safety)
for (i = 0; i < 1600; i++) {
Body(res, c, d, p, i);
}
}
llvm-svn: 267949
There's no existing test for this path, and I don't know how to expose
it in a regression test, but I'm assuming there's some reason this
path exists.
llvm-svn: 267813
Now the pass is just a tiny wrapper around the util. This lets us reuse
the logic elsewhere (done here for BuildLibCalls) instead of duplicating
it.
The next step is to have something like getOrInsertLibFunc that also
sets the attributes.
Differential Revision: http://reviews.llvm.org/D19470
llvm-svn: 267759
I tried to be as close as possible to the strongest check that
existed before; cleaning these up properly is left for future work.
Differential Revision: http://reviews.llvm.org/D19469
llvm-svn: 267758
Summary:
Refine the workaround from r266877 that attempts to prevent
renaming of locals in inline assembly, so that in addition to looking
for a llvm.used local value, that there is at least one inline assembly
call in the module. Otherwise, debug functions added to the llvm.used
can block importing/exporting unnecessarily.
Reviewers: joker.eph
Subscribers: llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D19573
llvm-svn: 267717
Summary:
cloneLoopWithPreheader() does not update LoopInfo for sub-loop of
the original loop being cloned. Add assert to ensure no sub-loops for loop being cloned.
Reviewers: anemet, ashutosh.nema, hfinkel
Subscribers: mzolotukhin, llvm-commits
Differential Revision: http://reviews.llvm.org/D15922
llvm-svn: 267671
Summary:
It is incorrect to compare TripCount (which is BECount + 1)
with extraiters (or Count) to check if we should enter unrolled
loop or not, because TripCount can potentially overflow
(when BECount is max unsigned integer).
While comparing BECount with (Count - 1) is overflow safe and
therefore correct.
Reviewer: hfinkel
Differential Revision: http://reviews.llvm.org/D19256
From: Evgeny Stupachenko <evstupac@gmail.com>
llvm-svn: 267662
The destination buffer that sprintf uses is restrict qualified, we do
not need to worry about derived pointers referenced via format
specifiers.
This reverts commit r267580.
llvm-svn: 267605
sprintf doesn't read or copy the terminating null byte from it's string
operands. sprintf will append it's own after processing all of the
format specifiers.
This fixes PR27526.
llvm-svn: 267580
When SimplifyCFG merges identical instructions from both sides of a diamond, it
can preserve !llvm.mem.parallel_loop_access (as it does with most of the other
metadata). There's no real data or control dependency change in this case.
llvm-svn: 267515
The original commit was reverted because of a buildbot problem with LazyCallGraph::SCC handling (not related to the OptBisect handling).
Differential Revision: http://reviews.llvm.org/D19172
llvm-svn: 267231
E.g. for:
!1 = {"llvm.distribute", i32 1}
it now returns the MDOperand for 1.
I will use this in LoopDistribution to check the value of the metadata.
Note that the change is backward-compatible with its current use in
LoopVersioningLICM. An Optional implicitly converts to a bool depending
whether it contains a value or not.
llvm-svn: 267190
Summary:
CachingMemorySSAWalker::invalidateInfo was using IsCall to determine
which cache map needed to be cleared of entries referring to the invalidated
MemoryAccess, but there could also be entries referring to it in the
other cache map (value entries, not key entries). This change just
clears both tables to be conservatively correct.
Also add a verifyRemoved() function, called when expensive
checks (i.e. XDEBUG) are enabled to verify that the invalidated
MemoryAccess object is not referenced in any of the caches.
Reviewers: dberlin, george.burgess.iv
Subscribers: mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D19388
llvm-svn: 267157
Re-layer the functions in the new (i.e., newly correct) post-order
traversals in ValueEnumerator (r266947) and ValueMapper (r266949).
Instead of adding a node to the worklist in a helper function and
returning a flag to say what happened, return the node itself. This
makes the code way cleaner: the worklist is local to the main function,
there is no flag for an early loop exit (since we can cleanly bury the
loop), and it's perfectly clear when pointers into the worklist might be
invalidated.
I'm fixing both algorithms in the same commit to avoid repeating the
commit message; if you take the time to understand one the other should
be easy. The diff itself isn't entirely obvious since the traversals
have some noise (i.e., things to do), but here's the high-level change:
auto helper = [&WL](T *Op) { auto helper = [](T **&I, T **E) {
=> while (I != E) {
if (shouldVisit(Op)) { T *Op = *I++;
WL.push(Op, Op->begin()); if (shouldVisit(Op)) {
return true; return Op;
} }
return false; return nullptr;
}; };
=>
WL.push(S, S->begin()); WL.push(S, S->begin());
while (!empty()) { while (!empty()) {
auto *N = WL.top().N; auto *N = WL.top().N;
auto *&I = WL.top().I; auto *&I = WL.top().I;
bool DidChange = false;
while (I != N->end())
if (helper(*I++)) { => if (T *Op = helper(I, N->end()) {
DidChange = true; WL.push(Op, Op->begin());
break; continue;
} }
if (DidChange)
continue;
POT.push(WL.pop()); => POT.push(WL.pop());
} }
Thanks to Mehdi for helping me find a better way to layer this.
llvm-svn: 267099
This patch implements a optimization bisect feature, which will allow optimizations to be selectively disabled at compile time in order to track down test failures that are caused by incorrect optimizations.
The bisection is enabled using a new command line option (-opt-bisect-limit). Individual passes that may be skipped call the OptBisect object (via an LLVMContext) to see if they should be skipped based on the bisect limit. A finer level of control (disabling individual transformations) can be managed through an addition OptBisect method, but this is not yet used.
The skip checking in this implementation is based on (and replaces) the skipOptnoneFunction check. Where that check was being called, a new call has been inserted in its place which checks the bisect limit and the optnone attribute. A new function call has been added for module and SCC passes that behaves in a similar way.
Differential Revision: http://reviews.llvm.org/D19172
llvm-svn: 267022
Summary:
`llvm.guard(false)` always bails out of the current compilation unit, so
we can prune any control flow following it.
Reviewers: hfinkel, pcc, reames
Subscribers: majnemer, reames, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D19245
llvm-svn: 266955
The iteratitive algorithm from r265456 claimed but failed to create a
post-order traversal. It had the same error that was fixed in the
ValueEnumerator in r266947: now, instead of pushing all operands on the
worklist at once, we pause whenever an operand gets pushed in order to
go depth-first (I know, it sounds obvious).
Sadly, I have no idea how to observe this from outside the algorithm and
so I haven't written a test. The output should be the same; it should
just use fewer temporary nodes now. I've added some comments that I
hope make the current logic clear enough it's unlikely to regress.
llvm-svn: 266949
Summary:
This patch prevents importing from (and therefore exporting from) any
module with a "llvm.used" local value. Local values need to be promoted
and renamed when importing, and their presense on the llvm.used variable
indicates that there are opaque uses that won't see the rename. One such
example is a use in inline assembly.
See also the discussion at:
http://lists.llvm.org/pipermail/llvm-dev/2016-April/098047.html
As part of this, move collectUsedGlobalVariables out of Transforms/Utils
and into IR/Module so that it can be used more widely. There are several
other places in LLVM that used copies of this code that can be cleaned
up as a follow on NFC patch.
Reviewers: joker.eph
Subscribers: pcc, llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D18986
llvm-svn: 266877
This linkage is *not* intended to express that a declaration refers
to a weak symbol, but that the symbol might not be present at link
time. I don't believe it was the intent.
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266856
This patch improves SimplifyCFG to catch cases like:
if (a < b) {
if (a > b) <- known to be false
unreachable;
}
Phabricator Revision: http://reviews.llvm.org/D18905
llvm-svn: 266767
Summary:
Need to use predecessors for reverse graph, successors for forward graph.
succ_iterator/pred_iterator are not compatible, this patch is all the work necessary to work around that (which is what everywhere else does). Not sure if there is a better way, so cc'ing some random folks to take a gander :)
Reviewers: dblaikie, qcolombet, echristo
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D18796
llvm-svn: 266718
Removed some unused headers, replaced some headers with forward class declarations.
Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'
Patch by Eugene Kosov <claprix@yandex.ru>
Differential Revision: http://reviews.llvm.org/D19219
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595
This catches two nullptr insertions into the ValueMap I missed in
r266567. I missed CloneFunction becuase it never calls RemapInstruction
directly. Here's one of the still-failing bots:
http://lab.llvm.org:8011/builders/clang-x64-ninja-win7/builds/11496
llvm-svn: 266570
Add an assertion to ValueMapper that prevents double-scheduling of
GlobalValues to remap, and fix the one place it happened. There are
tons of tests that fail with this assertion in place and without the
code change, so I'm not adding another.
Although it looks related, r266563 was, indeed, removing dead code.
AFAICT, this cross-file double-scheduling started in r266510 when the
cross-file recursion was removed.
llvm-svn: 266569
Apparently there isn't test coverage for all of these. I'd appreciate
if someone with could reproduce and send me something to reduce, but for
now I've just looked for users of RemapInstruction and MapValue and
ensured they don't accidentally insert nullptr. Here is one of the
bootstraps that caught:
http://lab.llvm.org:8011/builders/clang-x64-ninja-win7/builds/11494
llvm-svn: 266567
As a follow-up to r123058, assert that there are no null mappings in the
ValueMap instead of just ignoring them when they are there. There were
a couple of accidental insertions in CloneFunction so I cleaned those up
(caught by testcases).
llvm-svn: 266565
Rather than relying on the structural equivalence of DICompositeType to
merge type definitions, use an explicit map on the LLVMContext that
LLParser and BitcodeReader consult when constructing new nodes.
Each non-forward-declaration DICompositeType with a non-empty
'identifier:' field is stored/loaded from the type map, and the first
definiton will "win".
This map is opt-in: clients that expect ODR types from different modules
to be merged must call LLVMContext::ensureDITypeMap.
- Clients that just happen to load more than one Module in the same
LLVMContext won't magically merge types.
- Clients (like LTO) that want to continue to merge types based on ODR
identifiers should opt-in immediately.
I have updated LTOCodeGenerator.cpp, the two "linking" spots in
gold-plugin.cpp, and llvm-link (unless -disable-debug-info-type-map) to
set this.
With this in place, it will be straightforward to remove the DITypeRef
concept (i.e., referencing types by their 'identifier:' string rather
than pointing at them directly).
llvm-svn: 266549
Since the result of a mapped distinct node is known up front, it's more
efficient to map them separately from uniqued nodes. This commit pulls
them out of the post-order traversal and stores them in a worklist to be
remapped at the top-level.
This is essentially reapplying r244181 ("ValueMapper: Rotate distinct
node remapping algorithm") to the new iterative algorithm from r265456
("ValueMapper: Rewrite Mapper::mapMetadata without recursion").
Now that the traversal logic only handles uniqued MDNodes, it's much
simpler to inline it all into MDNodeMapper::createPOT (I've killed the
MDNodeMapper::push and MDNodeMapper::tryToPop helpers and localized the
traversal worklist).
The resulting high-level algorithm for MDNodeMapper::map now looks like
this:
- Distinct nodes are immediately mapped and added to
MDNodeMapper::DistinctWorklist using MDNodeMapper::mapDistinctNode.
- Uniqued nodes are mapped via MDNodeMapper::mapTopLevelUniquedNode,
which traverses the transitive uniqued subgraph of a node to
calculate uniqued node mappings in bulk.
- This is a simplified version of MDNodeMapper::map from before
this commit (originally r265456) that doesn't traverse through
any distinct nodes.
- Distinct nodes are added to MDNodeMapper::DistinctWorklist via
MDNodeMapper::mapDistinctNode.
- This uses MDNodeMapper::createPOT to fill a
MDNodeMapper::UniquedGraph (a post-order traversal and side
table), UniquedGraph::propagateChanges to track which uniqued
nodes need to change, and MDNodeMapper::mapNodesInPOT to create
the uniqued nodes.
- Placeholders for forward references are now only needed when
there's a uniquing cycle (a cycle of uniqued nodes unbroken by
distinct nodes). This is the key functionality change that
we're reintroducing (from r244181). As of r265456, a temporary
forward reference might be needed for any cycle that involved
uniqued nodes.
- After mapping the first node appropriately, MDNodeMapper::map works
through MDNodeMapper::DistinctWorklist. For each distinct node, its
operands are remapped with MDNodeMapper::mapDistinctNode and
MDNodeMapper::mapTopLevelUniquedNode until all nodes have been
mapped.
Sadly there's nothing observable I can test here; no real functionality
change, just a compile-time speedup from reduced malloc traffic.
llvm-svn: 266537
As a minor fixup to r266258, only track nodes that needed a placeholder
in CyclicNodes in MDNodeMapper::mapUniquedNodes. There should be no
observable functionality change, just some local memory savings because
CyclicNodes only needs to grow to accommodate nodes that are actually
involved in cycles. (This was the original intent of r266258, or else
the vector would have been called "ChangedNodes".)
llvm-svn: 266536
Stop memoizing ConstantAsMetadata in ValueMapper::mapMetadata. Now we
have to recompute it, but these metadata aren't particularly common, and
it restricts the lifetime of the Metadata map unnecessarily.
(The motivation is that I have a patch which uses a single Metadata map
for the lifetime of IRMover. Mehdi profiled r266446 with the patch
applied and we saw a pretty big speedup in lib/Linker.)
llvm-svn: 266513
This reverts commit r266507, reapplying r266503 (and r266505
"ValueMapper: Use API from r266503 in unit tests, NFC") completely
unchanged.
I reverted because of a bot failure here:
http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/16810/
However, looking more closely, the failure was from a host-compiler
crash (clang 3.7.1) when building:
lib/CodeGen/AsmPrinter/CMakeFiles/LLVMAsmPrinter.dir/DwarfAccelTable.cpp.o
I didn't modify that file, or anything it includes, with that commit.
The next build (which hadn't picked up my revert) got past it:
http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/16811/
I think this was just unfortunate timing. I suppose the bot must be
flakey.
llvm-svn: 266510
This reverts commit r266503, in case it's the root cause of this bot
failure:
http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/16810
I'm also reverting r266505 -- "ValueMapper: Use API from r266503 in unit
tests, NFC" -- since it's in the way.
llvm-svn: 266507
Eliminate co-recursion of Mapper::mapValue through
ValueMaterializer::materializeInitFor, through a major redesign of the
ValueMapper.cpp interface.
- Expose a ValueMapper class that controls the entry points to the
mapping algorithms.
- Change IRLinker to use ValueMapper directly, rather than
llvm::RemapInstruction, llvm::MapValue, etc.
- Use (e.g.) ValueMapper::scheduleMapGlobalInit to add mapping work to
a worklist in ValueMapper instead of recursing.
There were two fairly major complications.
Firstly, IRLinker::linkAppendingVarProto incorporates an on-the-fly IR
ugprade that I had to split apart. Long-term, this upgrade should be
done in the bitcode reader (and we should only accept the "new" form),
but for now I've just made it work and added a FIXME. The hold-op is
that we need to deprecate C API that relies on this.
Secondly, IRLinker has special logic to correctly implement aliases with
comdats, and uses two ValueToValueMapTy instances and two
ValueMaterializers. I supported this by allowing clients to register an
alternate mapping context, whose MCID can be passed in when scheduling
new work.
While out of scope for this commit, it should now be straightforward to
remove recursion from Mapper::mapValue.
llvm-svn: 266503
Change Mapper::VM to a pointer and add a `getVM()` accessor for it.
While this has no functionality change, it minimizes the diff on an
upcoming patch that allows switching between instances of
ValueToValueMapTy on a single Mapper instance.
llvm-svn: 266490
Currently each Function points to a DISubprogram and DISubprogram has a
scope field. For member functions the scope is a DICompositeType. DIScopes
point to the DICompileUnit to facilitate type uniquing.
Distinct DISubprograms (with isDefinition: true) are not part of the type
hierarchy and cannot be uniqued. This change removes the subprograms
list from DICompileUnit and instead adds a pointer to the owning compile
unit to distinct DISubprograms. This would make it easy for ThinLTO to
strip unneeded DISubprograms and their transitively referenced debug info.
Motivation
----------
Materializing DISubprograms is currently the most expensive operation when
doing a ThinLTO build of clang.
We want the DISubprogram to be stored in a separate Bitcode block (or the
same block as the function body) so we can avoid having to expensively
deserialize all DISubprograms together with the global metadata. If a
function has been inlined into another subprogram we need to store a
reference the block containing the inlined subprogram.
Attached to https://llvm.org/bugs/show_bug.cgi?id=27284 is a python script
that updates LLVM IR testcases to the new format.
http://reviews.llvm.org/D19034
<rdar://problem/25256815>
llvm-svn: 266446
This is almost identical to:
http://reviews.llvm.org/rL264527
This doesn't solve PR27344; it just allows the profile weights to survive.
To solve the bug, we need to use the profile weights in the backend.
llvm-svn: 266442
Fix a major bug from r265456. Although it's now much rarer, ValueMapper
sometimes has to duplicate cycles. The
might-transitively-reference-a-temporary counts don't decrement on their
own when there are cycles, and you need to call MDNode::resolveCycles to
fix it.
r265456 was checking the input nodes to see if they were unresolved.
This is useless; they should never be unresolved. Instead we should
check the output nodes and resolve cycles on them.
llvm-svn: 266258
Summary:
For correct handling of alias to nameless
function, we need to be able to refer them through a GUID in the summary.
Here we name them using a hash of the non-private global names in the module.
Reviewers: tejohnson
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D18883
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266132
This is more robust to changes in the link ordering.
Differential Revision: http://reviews.llvm.org/D18946
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266018
This patch ensures that when we detect first-order recurrences, we reject a phi
node if its previous value is also a phi node. During vectorization the initial
and previous values of the recurrence are shuffled together to create the value
for the current iteration. However, phi nodes are not widened like other
instructions. This fixes PR27246.
Differential Revision: http://reviews.llvm.org/D18971
llvm-svn: 265983
Summary:
If we can prove that an op.with.overflow intrinsic does not overflow, we
can get rid of the intrinsic, and replace it with non-wrapping
arithmetic.
Reviewers: atrick, regehr
Subscribers: sanjoy, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D18685
llvm-svn: 265913
Strip out the remapping parts of IRLinker::linkFunctionBody and put them
in ValueMapper.cpp under the name Mapper::remapFunction (with a
top-level entry-point llvm::RemapFunction).
This is a nice cleanup on its own since it puts the remapping code
together and shares a single Mapper context for the entire
IRLinker::linkFunctionBody Call. Besides that, this will make it easier
to break the co-recursion between IRMover.cpp and ValueMapper.cpp in
follow ups.
llvm-svn: 265835
Use Mapper::mapValue instead of llvm::MapValue from
Mapper::remapInstruction when mapping an incoming block for a PHINode
(follow-up to r265832). This will implicitly pass along the
Materializer argument, but when this code was added in r133513 there was
no Materializer argument. I suspect this call to MapValue was just
missed in r182776 since it's not observable (basic blocks can't be
materialized, and they don't reference other values).
llvm-svn: 265833
Add Mapper::remapInstruction, move the guts of llvm::RemapInstruction
into it, and use the same Mapper for most of the calls to MapValue and
MapMetadata. There should be no functionality change here.
I left off the call to MapValue that wasn't passing in a Materializer
argument (for basic blocks of PHINodes). It shouldn't change
functionality either, but I'm suspicious enough to commit separately.
llvm-svn: 265832
Prevent the Metadata side-table in ValueMap from growing unnecessarily
when RF_NoModuleLevelChanges. As a drive-by, make ValueMap::hasMD,
which apparently had no users until I used it here for testing, actually
compile.
llvm-svn: 265828
Stop adding MDString to the Metadata section of the ValueMap in
MapMetadata. It blows up the size of the map for no benefit, since we
can always return quickly anyway.
There is a potential follow-up that I don't think I'll push on right
away, but maybe someone else is interested: stop checking for a
pre-mapped MDString, and move the `isa<MDString>()` checks in
Mapper::mapSimpleMetadata and MDNodeMapper::getMappedOp in front of the
`VM.getMappedMD()` calls. While this would preclude explicitly
remapping MDStrings it would probably be a little faster.
llvm-svn: 265827
This reverts commit r265765, reapplying r265759 after changing a call from
LocalAsMetadata::get to ValueAsMetadata::get (and adding a unit test). When a
local value is mapped to a constant (like "i32 %a" => "i32 7"), the new debug
intrinsic operand may no longer be pointing at a local.
http://lab.llvm.org:8080/green/job/clang-stage1-configure-RA_build/19020/
The previous coommit message follows:
--
This is a partial re-commit -- maybe more of a re-implementation -- of
r265631 (reverted in r265637).
This makes RF_IgnoreMissingLocals behave (almost) consistently between
the Value and the Metadata hierarchy. In particular:
- MapValue returns nullptr or "metadata !{}" for missing locals in
MetadataAsValue/LocalAsMetadata bridging paris, depending on
the RF_IgnoreMissingLocals flag.
- MapValue doesn't memoize LocalAsMetadata-related results.
- MapMetadata no longer deals with LocalAsMetadata or
RF_IgnoreMissingLocals at all. (This wasn't in r265631 at all, but
I realized during testing it would make the patch simpler with no
loss of generality.)
r265631 went too far, making both functions universally ignore
RF_IgnoreMissingLocals. This broke building (e.g.) compiler-rt.
Reassociate (and possibly other passes) don't currently maintain
dominates-use invariants for metadata operands, resulting in IR like
this:
define void @foo(i32 %arg) {
call void @llvm.some.intrinsic(metadata i32 %x)
%x = add i32 1, i32 %arg
}
If the inliner chooses to inline @foo into another function, then
RemapInstruction will call `MapValue(metadata i32 %x)` and assert that
the return is not nullptr.
I've filed PR27273 to add a Verifier check and fix the underlying
problem in the optimization passes.
As a workaround, return `!{}` instead of nullptr for unmapped
LocalAsMetadata when RF_IgnoreMissingLocals is unset. Otherwise, match
the behaviour of r265631.
Original commit message:
ValueMapper: Make LocalAsMetadata match function-local Values
Start treating LocalAsMetadata similarly to function-local members of
the Value hierarchy in MapValue and MapMetadata.
- Don't memoize them.
- Return nullptr if they are missing.
This also cleans up ConstantAsMetadata to stop listening to the
RF_IgnoreMissingLocals flag.
llvm-svn: 265768
Summary:
Fixes PR26774.
If you're aware of the issue, feel free to skip the "Motivation"
section and jump directly to "This patch".
Motivation:
I define "refinement" as discarding behaviors from a program that the
optimizer has license to discard. So transforming:
```
void f(unsigned x) {
unsigned t = 5 / x;
(void)t;
}
```
to
```
void f(unsigned x) { }
```
is refinement, since the behavior went from "if x == 0 then undefined
else nothing" to "nothing" (the optimizer has license to discard
undefined behavior).
Refinement is a fundamental aspect of many mid-level optimizations done
by LLVM. For instance, transforming `x == (x + 1)` to `false` also
involves refinement since the expression's value went from "if x is
`undef` then { `true` or `false` } else { `false` }" to "`false`" (by
definition, the optimizer has license to fold `undef` to any non-`undef`
value).
Unfortunately, refinement implies that the optimizer cannot assume
that the implementation of a function it can see has all of the
behavior an unoptimized or a differently optimized version of the same
function can have. This is a problem for functions with comdat
linkage, where a function can be replaced by an unoptimized or a
differently optimized version of the same source level function.
For instance, FunctionAttrs cannot assume a comdat function is
actually `readnone` even if it does not have any loads or stores in
it; since there may have been loads and stores in the "original
function" that were refined out in the currently visible variant, and
at the link step the linker may in fact choose an implementation with
a load or a store. As an example, consider a function that does two
atomic loads from the same memory location, and writes to memory only
if the two values are not equal. The optimizer is allowed to refine
this function by first CSE'ing the two loads, and the folding the
comparision to always report that the two values are equal. Such a
refined variant will look like it is `readonly`. However, the
unoptimized version of the function can still write to memory (since
the two loads //can// result in different values), and selecting the
unoptimized version at link time will retroactively invalidate
transforms we may have done under the assumption that the function
does not write to memory.
Note: this is not just a problem with atomics or with linking
differently optimized object files. See PR26774 for more realistic
examples that involved neither.
This patch:
This change introduces a new set of linkage types, predicated as
`GlobalValue::mayBeDerefined` that returns true if the linkage type
allows a function to be replaced by a differently optimized variant at
link time. It then changes a set of IPO passes to bail out if they see
such a function.
Reviewers: chandlerc, hfinkel, dexonsmith, joker.eph, rnk
Subscribers: mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D18634
llvm-svn: 265762
This is a partial re-commit -- maybe more of a re-implementation -- of
r265631 (reverted in r265637).
This makes RF_IgnoreMissingLocals behave (almost) consistently between
the Value and the Metadata hierarchy. In particular:
- MapValue returns nullptr or "metadata !{}" for missing locals in
MetadataAsValue/LocalAsMetadata bridging paris, depending on
the RF_IgnoreMissingLocals flag.
- MapValue doesn't memoize LocalAsMetadata-related results.
- MapMetadata no longer deals with LocalAsMetadata or
RF_IgnoreMissingLocals at all. (This wasn't in r265631 at all, but
I realized during testing it would make the patch simpler with no
loss of generality.)
r265631 went too far, making both functions universally ignore
RF_IgnoreMissingLocals. This broke building (e.g.) compiler-rt.
Reassociate (and possibly other passes) don't currently maintain
dominates-use invariants for metadata operands, resulting in IR like
this:
define void @foo(i32 %arg) {
call void @llvm.some.intrinsic(metadata i32 %x)
%x = add i32 1, i32 %arg
}
If the inliner chooses to inline @foo into another function, then
RemapInstruction will call `MapValue(metadata i32 %x)` and assert that
the return is not nullptr.
I've filed PR27273 to add a Verifier check and fix the underlying
problem in the optimization passes.
As a workaround, return `!{}` instead of nullptr for unmapped
LocalAsMetadata when RF_IgnoreMissingLocals is unset. Otherwise, match
the behaviour of r265631.
Original commit message:
ValueMapper: Make LocalAsMetadata match function-local Values
Start treating LocalAsMetadata similarly to function-local members of
the Value hierarchy in MapValue and MapMetadata.
- Don't memoize them.
- Return nullptr if they are missing.
This also cleans up ConstantAsMetadata to stop listening to the
RF_IgnoreMissingLocals flag.
llvm-svn: 265759
Remove the assertion that disallowed the combination, since
RF_IgnoreMissingLocals should have no effect on globals. As it happens,
RF_NullMapMissingGlobalValues asserted in MapValue(Constant*,...), so I
also changed a cast to a cast_or_null to get my test passing.
llvm-svn: 265633
Start treating LocalAsMetadata similarly to function-local members of
the Value hierarchy in MapValue and MapMetadata.
- Don't memoize them.
- Return nullptr if they are missing.
This also cleans up ConstantAsMetadata to stop listening to the
RF_IgnoreMissingLocals flag.
llvm-svn: 265631
Clarify what this RemapFlag actually means.
- Change the flag name to match its intended behaviour.
- Clearly document that it's not supposed to affect globals.
- Add a host of FIXMEs to indicate how to fix the behaviour to match
the intent of the flag.
RF_IgnoreMissingLocals should only affect the behaviour of
RemapInstruction for function-local operands; namely, for operands of
type Argument, Instruction, and BasicBlock. Currently, it is *only*
passed into RemapInstruction calls (and the transitive MapValue calls
that it makes).
When I split Metadata from Value I didn't understand the flag, and I
used it in a bunch of places for "global" metadata.
This commit doesn't have any functionality change, but prepares to
cleanup MapMetadata and MapValue.
llvm-svn: 265628
Updating dominators for exit-blocks of the unrolled loops is not enough,
as shown in PR27157. The proper way is to update dominators for all
dominance-children of original loop blocks.
llvm-svn: 265605
Summary:
In the context of http://wg21.link/lwg2445 C++ uses the concept of
'stronger' ordering but doesn't define it properly. This should be fixed
in C++17 barring a small question that's still open.
The code currently plays fast and loose with the AtomicOrdering
enum. Using an enum class is one step towards tightening things. I later
also want to tighten related enums, such as clang's
AtomicOrderingKind (which should be shared with LLVM as a 'C++ ABI'
enum).
This change touches a few lines of code which can be improved later, I'd
like to keep it as NFC for now as it's already quite complex. I have
related changes for clang.
As a follow-up I'll add:
bool operator<(AtomicOrdering, AtomicOrdering) = delete;
bool operator>(AtomicOrdering, AtomicOrdering) = delete;
bool operator<=(AtomicOrdering, AtomicOrdering) = delete;
bool operator>=(AtomicOrdering, AtomicOrdering) = delete;
This is separate so that clang and LLVM changes don't need to be in sync.
Reviewers: jyknight, reames
Subscribers: jyknight, llvm-commits
Differential Revision: http://reviews.llvm.org/D18775
llvm-svn: 265602
r265273 added Mapper::mapBlockAddress, which delays mapping a
blockaddress value until the function has a body. The condition was
backwards, and should be checking Function::empty instead of
GlobalValue::isDeclaration.
llvm-svn: 265508
Add a common parent class for ConstantArray, ConstantVector, and
ConstantStruct called ConstantAggregate. These are the aggregate
subclasses of Constant that take operands.
This is mainly a cleanup, adding common `isa` target and removing
duplicated code. However, it also simplifies caching which constants
point transitively at `GlobalValue` (a possible future direction).
llvm-svn: 265466
This commit completely rewrites Mapper::mapMetadata (the implementation
of llvm::MapMetadata) using an iterative algorithm. The guts of the new
algorithm are in MDNodeMapper::map, the entry function in a new class.
Previously, Mapper::mapMetadata performed a recursive exploration of the
graph with eager "just in case there's a reason" malloc traffic.
The new algorithm has these benefits:
- New nodes and temporaries are not created eagerly.
- Uniquing cycles are not duplicated (see new unit test).
- No recursion.
Given a node to map, it does this:
1. Use a worklist to perform a post-order traversal of the transitively
referenced unmapped nodes.
2. Track which nodes will change operands, and which will have new
addresses in the mapped scheme. Propagate the changes through the
POT until fixed point, to pick up uniquing cycles that need to
change.
3. Map all the distinct nodes without touching their operands. If
RF_MoveDistinctMetadata, they get mapped to themselves; otherwise,
they get mapped to clones.
4. Map the uniqued nodes (bottom-up), lazily creating temporaries for
forward references as needed.
5. Remap the operands of the distinct nodes.
Mehdi helped me out by profiling this with -flto=thin. On his workload
(importing/etc. for opt.cpp), MapMetadata sped up by 15%, contributed
about 50% less to persistent memory, and made about 100x fewer calls to
malloc. The speedup is less than I'd hoped. The profile mainly blames
DenseMap lookups; perhaps there's a way to reduce them (e.g., by
disallowing remapping of MDString).
It would be nice to break the strange remaining recursion on the Value
side: MapValue => materializeInitFor => RemapInstruction => MapValue. I
think we could do this by having materializeInitFor return a worklist of
things to be remapped.
llvm-svn: 265456
Remove a few old FIXMEs from the original commit of the Metadata/Value
split in r223802. These are commented out assertions to the effect that
calls between mapValue and mapMetadata never return nullptr.
(The only behaviour change is that Mapper::mapSimpleMetadata memoizes
the nullptr return.)
When I originally rewrote the mapping code, I thought we could be
stricter in the new metadata hierarchy and never return nullptr when
RF_NullMapMissingGlobalValues was off. It's still not entirely clear to
me why these assertions failed (a few months ago, I had a theory that I
forgot to write down, but that's helping no one).
Understood or not, I no longer see how these commented-out assertions
would be useful. I'm relegating them to the annals of source control
before making significant changes to ValueMapper.cpp.
llvm-svn: 265282
This adds an assertion to maintain the property from r265273. When
Mapper::mapSimpleMetadata calls Mapper::mapValue, it should not find its
way back to mapMetadataImpl. This guarantees that mapSimpleMetadata is
not involved in any recursion.
Since Mapper::mapValue calls out to arbitrary materializers, we need to
save a bit on the ValueMap to make this assertion effective.
There should be no functionality change here. This co-recursion should
already have been impossible.
llvm-svn: 265276
The main change is to delay materializing GlobalValue initializers from
Mapper::mapValue until Mapper::~Mapper. This effectively removes all
recursion from mapSimplifiedMetadata, as promised in r265270.
mapSimplifiedMetadata calls mapValue for ConstantAsMetadata nodes to
find the mapped constant, and now it shouldn't be possible for mapValue
to indirectly re-invoke mapMetadata. I'll add an assertion to that
effect in a follow-up (separated so that the assertion can easily be
reverted independently, if it comes to that).
This a step toward a broader goal: converting Mapper::mapMetadataImpl
from a recursive to an iterative algorithm.
When a BlockAddress points at a BasicBlock inside an unmaterialized
function body, we need to delay it until the function body is
materialized in Mapper::~Mapper. This commit creates a temporary
BasicBlock and returns a new BlockAddress, then RAUWs the BasicBlock
once it is known. This situation should be extremely rare since a
BlockAddress is usually used from within the function it's referencing
(and BlockAddress itself is rare).
There should be no observable functionality change.
llvm-svn: 265273
Split out a helper for mapping metadata without operands. This is any
metadata that is not an MDNode, and any MDNode where the answer is known
without looking at operands.
Through some weird twists, this function is co-recursive:
mapSimpleMetadata
=> MapValue
=> materializeInitFor
=> linkFunctionBody
=> RemapInstructions
=> MapMetadata
=> mapSimpleMetadata
I plan to break the recursion in a follow-up.
llvm-svn: 265270
Davide Italiano