Summary:
This "pass" eagerly creates div and rem instructions even when only one
is needed -- it relies on a later pass (machine DCE?) to clean them up.
This is problematic not just from a cleanliness perspective (this pass
is running during CodeGenPrepare, so should leave the IR in a better
state), but it also creates a problem for instruction selection. If we
always have a div+rem, isel will always select a divrem instruction (if
possible), even when a single div or rem would do.
Specifically, in NVPTX, we want to compute rem from the output of div,
if available. But if a div is not available, we want to leave the rem
alone. This transformation is overeager if div is always available.
Because this code runs as part of CodeGenPrepare, it's nontrivial to
write a test for this change. But this will effectively be tested by
a later patch which adds the aforementioned change to NVPTX isel.
Reviewers: tra
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26088
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285460 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
In BypassSlowDivision's short-dividend path, we would create e.g.
udiv exact i32 %a, %b
"exact" here means that we are asserting that %a is a multiple of %b.
But we have no reason to believe this must be true -- this is just a
bug, as far as I can tell.
Reviewers: tra
Subscribers: jholewinski, llvm-commits
Differential Revision: https://reviews.llvm.org/D26097
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285459 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes PR 30784. Discussed with Justin, who pointed out that
in the new PassManager infrastructure we can have more fine-grained
control on which analyses we want to preserve, but this is the
best we can do with the current infrastructure.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285380 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This is in preparation for a change to utilize this flag for symbols
referenced/defined in either inline or module level assembly.
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26048
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285376 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: LICM may hoist instructions to preheader speculatively. Before code generation, we need to sink down the hoisted instructions inside to loop if it's beneficial. This pass is a reverse of LICM: looking at instructions in preheader and sinks the instruction to basic blocks inside the loop body if basic block frequency is smaller than the preheader frequency.
Reviewers: hfinkel, davidxl, chandlerc
Subscribers: anna, modocache, mgorny, beanz, reames, dberlin, chandlerc, mcrosier, junbuml, sanjoy, mzolotukhin, llvm-commits
Differential Revision: https://reviews.llvm.org/D22778
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285308 91177308-0d34-0410-b5e6-96231b3b80d8
After successfull horizontal reduction vectorization attempt for PHI node
vectorizer tries to update root binary op by combining vectorized tree
and the ReductionPHI node. But during vectorization this ReductionPHI
can be vectorized itself and replaced by the `undef` value, while the
instruction itself is marked for deletion. This 'marked for deletion'
PHI node then can be used in new binary operation, causing "Use still
stuck around after Def is destroyed" crash upon PHI node deletion.
Also the test is fixed to make it perform actual testing.
Differential Revision: https://reviews.llvm.org/D25671
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285286 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: This patch introduces updateDiscriminator to DILocation so that it can be directly called by AddDiscriminator. It also makes it easier to update the discriminator later.
Reviewers: dnovillo, dblaikie, aprantl, echristo
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D25959
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285207 91177308-0d34-0410-b5e6-96231b3b80d8
1. Use 'auto' with dyn_cast.
2. Variables start with a capital letter.
3. Use proper punctuation in comments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285200 91177308-0d34-0410-b5e6-96231b3b80d8
When the loop exit condition is canonicalized as a != compaison, reuse the
debug location of the original (non canonical) comparison.
Before this patch, the debug location of the new icmp was obtained from the
loop latch terminator. This patch fixes the issue by correctly setting the
IRBuilder's "current debug location" to the location of the original compare.
Differential Revision: https://reviews.llvm.org/D25953
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285185 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Select instruction annotation in IR PGO uses the edge count to infer the
branch count. It's currently placed in setInstrumentedCounts() where
no all the BB counts have been computed. This leads to wrong branch weights.
Move the annotation after all BB counts are populated.
Reviewers: davidxl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D25961
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285128 91177308-0d34-0410-b5e6-96231b3b80d8
The original patch of the A->B->A BitCast optimization was reverted by r274094 because it may cause infinite loop inside compiler https://llvm.org/bugs/show_bug.cgi?id=27996.
The problem is with following code
xB = load (type B);
xA = load (type A);
+yA = (A)xB; B -> A
+zAn = PHI[yA, xA]; PHI
+zBn = (B)zAn; // A -> B
store zAn;
store zBn;
optimizeBitCastFromPhi generates
+zBn = (B)zAn; // A -> B
and expects it will be combined with the following store instruction to another
store zAn
Unfortunately before combineStoreToValueType is called on the store instruction, optimizeBitCastFromPhi is called on the new BitCast again, and this pattern repeats indefinitely.
optimizeBitCastFromPhi only generates BitCast for load/store instructions, only the BitCast before store can cause the reexecution of optimizeBitCastFromPhi, and BitCast before store can easily be handled by InstCombineLoadStoreAlloca.cpp. So the solution to the problem is if all users of a CI are store instructions, we should not do optimizeBitCastFromPhi on it. Then optimizeBitCastFromPhi will not be called on the new BitCast instructions.
Differential Revision: https://reviews.llvm.org/D23896
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285116 91177308-0d34-0410-b5e6-96231b3b80d8
When we predicate an instruction (div, rem, store) we place the instruction in
its own basic block within the vectorized loop. If a predicated instruction has
scalar operands, it's possible to recursively sink these scalar expressions
into the predicated block so that they might avoid execution. This patch sinks
as much scalar computation as possible into predicated blocks. We previously
were able to sink such operands only if they were extractelement instructions.
Differential Revision: https://reviews.llvm.org/D25632
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285097 91177308-0d34-0410-b5e6-96231b3b80d8
This adds a new function to DebugInfo.cpp that takes an llvm::Module
as input and removes all debug info metadata that is not directly
needed for line tables, thus effectively stripping all type and
variable information from the module.
The primary motivation for this feature was the bitcode work flow
(cf. http://lists.llvm.org/pipermail/llvm-dev/2016-June/100643.html
for more background). This is not wired up yet, but will be in
subsequent patches. For testing, the new functionality is exposed to
opt with a -strip-nonlinetable-debuginfo option.
The secondary use-case (and one that works right now!) is as a
reduction pass in bugpoint. I added two new bugpoint options
(-disable-strip-debuginfo and -disable-strip-debug-types) to control
the new features. By default it will first attempt to remove all debug
information, then only the type info, and then proceed to hack at any
remaining MDNodes.
Thanks to Adrian Prantl for stewarding this patch!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285094 91177308-0d34-0410-b5e6-96231b3b80d8
When indvars widened an induction variable, the debug location for the loop
increment computation was incorrectly set equal to the debug loc of the loop
latch terminator.
This patch fixes the issue by propagating the correct location from the
original loop increment instruction to the new widened increment.
Differential Revision: https://reviews.llvm.org/D25872
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285083 91177308-0d34-0410-b5e6-96231b3b80d8
Now that MemorySSA keeps track of whether MemoryUses are optimized, use
getClobberingMemoryAccess() to check MemoryUse memory dependencies since
it should no longer be so expensive.
This is a follow-up change to https://reviews.llvm.org/D25881
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285080 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes a bug in the handling of lexical scopes, when more than one
scope is defined on the same line or functions are inlined into call
sites that are on the same line as the function definition. This
situation can easily happen in macro expansions.
The problem is solved by introducing a SmallDenseMap<DIScope *,
DILexicalBlockFile *, 1> that keeps track of all the different lexical
scopes that share a line/file location.
Fixes PR30681.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284998 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When using MemorySSA, re-optimize MemoryPhis when removing a store since
this may create MemoryPhis with all identical arguments.
Also, when using MemorySSA to check if two MemoryUses are reading from
the same version of the heap, use the defining access instead of calling
getClobberingAccess, since the latter can currently result in many more
AA calls. Once the MemorySSA use optimization tracking changes are
done, we can remove this limitation, which should result in more loads
being CSE'd.
Reviewers: dberlin
Subscribers: mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D25881
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284984 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
These are good candidates for jump threading. This enables later opts
(such as InstCombine) to combine instructions from the selects with
instructions out of the selects. SimplifyCFG will fold the select
again if unfolding wasn't worth it.
Patch by James Molloy and Pablo Barrio.
Reviewers: reames, bkramer, mcrosier, gberry, haicheng, jmolloy, sebpop
Subscribers: jojo, rengolin, llvm-commits
Differential Revision: https://reviews.llvm.org/D25477
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284971 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Utility pass to remove gc.relocates created by rewrite statepoints for GC.
With respect to safepoint verification, the IR generated would be incorrect, and cannot run
as such.
This would be a single transformation on the final optimized IR.
The benefit of the pass is for easy analysis when the IRs are 'polluted' by too
many gc.relocates.
Added tests.
test run: All RS4GC tests with -verify option. Local downstream tests on large
IR files. This also works when the pointer being gc.relocated is another
gc.relocate.
Reviewers: sanjoy, reames
Subscribers: beanz, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D25096
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284855 91177308-0d34-0410-b5e6-96231b3b80d8
When we have a loop with a known upper bound on the number of iterations, and
furthermore know that either the number of iterations will be either exactly
that upper bound or zero, then we can fully unroll up to that upper bound
keeping only the first loop test to check for the zero iteration case.
Most of the work here is in plumbing this 'max-or-zero' information from the
part of scalar evolution where it's detected through to loop unrolling. I've
also gone for the safe default of 'false' everywhere but howManyLessThans which
could probably be improved.
Differential Revision: https://reviews.llvm.org/D25682
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284818 91177308-0d34-0410-b5e6-96231b3b80d8
There's no agreement about this patch. I personally find the
PRE machinery of the current GVN hard enough to reason about
that I'm not sure I'll try to land this again, instead of working
on the rewrite).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284796 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This allows us to mark when uses have been optimized.
This lets us avoid rewalking (IE when people call getClobberingAccess on everything), and also
enables us to later relax the requirement of use optimization during updates with less cost.
Reviewers: george.burgess.iv
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D25172
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284771 91177308-0d34-0410-b5e6-96231b3b80d8
All of these existed because MSVC 2013 was unable to synthesize default
move ctors. We recently dropped support for it so all that error-prone
boilerplate can go.
No functionality change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284721 91177308-0d34-0410-b5e6-96231b3b80d8
Some instructions from the original loop, when vectorized, can become trivially
dead. This happens because of the way we structure the new loop. For example,
we create new induction variables and induction variable "steps" in the new
loop. Thus, when we go to vectorize the original induction variable update, it
may no longer be needed due to the instructions we've already created. This
patch prevents us from creating these redundant instructions. This reduces code
size before simplification and allows greater flexibility in code generation
since we have fewer unnecessary instruction uses.
Differential Revision: https://reviews.llvm.org/D25631
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284631 91177308-0d34-0410-b5e6-96231b3b80d8
This change is motivated by the case when IndVarSimplify doesn't widen a comparison of IV increment because it can't prove IV increment being non-negative. We end up with a redundant trunc of the widened increment on this example.
for.body:
%i = phi i32 [ %start, %for.body.lr.ph ], [ %i.inc, %for.inc ]
%within_limits = icmp ult i32 %i, 64
br i1 %within_limits, label %continue, label %for.end
continue:
%i.i64 = zext i32 %i to i64
%arrayidx = getelementptr inbounds i32, i32* %base, i64 %i.i64
%val = load i32, i32* %arrayidx, align 4
br label %for.inc
for.inc:
%i.inc = add nsw nuw i32 %i, 1
%cmp = icmp slt i32 %i.inc, %limit
br i1 %cmp, label %for.body, label %for.end
There is a range check inside of the loop which guarantees the IV to be non-negative. NSW on the increment guarantees that the increment is also non-negative. Teach IndVarSimplify to use the range check to prove non-negativity of loop increments.
Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D25738
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284629 91177308-0d34-0410-b5e6-96231b3b80d8
