| From cc2bebe039374d6f0c8251ac322f8f7148d85950 Mon Sep 17 00:00:00 2001 |
| From: Bill Wendling <isanbard@gmail.com> |
| Date: Wed, 14 Aug 2019 16:44:07 +0000 |
| Subject: [PATCH] Ignore indirect branches from callbr. |
| |
| Summary: |
| We can't speculate around indirect branches: indirectbr and invoke. The |
| callbr instruction needs to be included here. |
| |
| Reviewers: nickdesaulniers, manojgupta, chandlerc |
| |
| Reviewed By: chandlerc |
| |
| Subscribers: llvm-commits |
| |
| Tags: #llvm |
| |
| Differential Revision: https://reviews.llvm.org/D66200 |
| |
| llvm-svn: 368873 |
| --- |
| .../Transforms/Scalar/SpeculateAroundPHIs.cpp | 6 ++- |
| .../Transforms/SpeculateAroundPHIs/pr42991.ll | 44 +++++++++++++++++++ |
| 2 files changed, 48 insertions(+), 2 deletions(-) |
| create mode 100644 llvm/test/Transforms/SpeculateAroundPHIs/pr42991.ll |
| |
| diff --git a/llvm/lib/Transforms/Scalar/SpeculateAroundPHIs.cpp b/llvm/lib/Transforms/Scalar/SpeculateAroundPHIs.cpp |
| index c13fb3e0451..e6db11f47ea 100644 |
| --- a/llvm/lib/Transforms/Scalar/SpeculateAroundPHIs.cpp |
| +++ b/llvm/lib/Transforms/Scalar/SpeculateAroundPHIs.cpp |
| @@ -777,8 +777,10 @@ static bool tryToSpeculatePHIs(SmallVectorImpl<PHINode *> &PNs, |
| // speculation if the predecessor is an invoke. This doesn't seem |
| // fundamental and we should probably be splitting critical edges |
| // differently. |
| - if (isa<IndirectBrInst>(PredBB->getTerminator()) || |
| - isa<InvokeInst>(PredBB->getTerminator())) { |
| + const auto *TermInst = PredBB->getTerminator(); |
| + if (isa<IndirectBrInst>(TermInst) || |
| + isa<InvokeInst>(TermInst) || |
| + isa<CallBrInst>(TermInst)) { |
| LLVM_DEBUG(dbgs() << " Invalid: predecessor terminator: " |
| << PredBB->getName() << "\n"); |
| return false; |
| diff --git a/llvm/test/Transforms/SpeculateAroundPHIs/pr42991.ll b/llvm/test/Transforms/SpeculateAroundPHIs/pr42991.ll |
| new file mode 100644 |
| index 00000000000..4aef689f53d |
| --- /dev/null |
| +++ b/llvm/test/Transforms/SpeculateAroundPHIs/pr42991.ll |
| @@ -0,0 +1,44 @@ |
| +; RUN: opt -S -passes=spec-phis %s |
| + |
| +; This testcase crashes during the speculate around PHIs pass. The pass however |
| +; results in no changes. |
| + |
| +define i32 @test1() { |
| +entry: |
| + callbr void asm sideeffect "", "X,X,~{dirflag},~{fpsr},~{flags}"(i8* blockaddress(@test1, %return), i8* blockaddress(@test1, %f)) |
| + to label %asm.fallthrough [label %return, label %f] |
| + |
| +asm.fallthrough: |
| + br label %return |
| + |
| +f: |
| + br label %return |
| + |
| +return: |
| + %retval.0 = phi i32 [ 0, %f ], [ 1, %asm.fallthrough ], [ 1, %entry ] |
| + ret i32 %retval.0 |
| +} |
| + |
| +define void @test2() { |
| +entry: |
| + br label %tailrecurse |
| + |
| +tailrecurse: |
| + %call = tail call i32 @test3() |
| + %tobool1 = icmp eq i32 %call, 0 |
| + callbr void asm sideeffect "", "X,X,~{dirflag},~{fpsr},~{flags}"(i8* blockaddress(@test2, %test1.exit), i8* blockaddress(@test2, %f.i)) |
| + to label %if.end6 [label %test1.exit, label %f.i] |
| + |
| +f.i: |
| + br label %test1.exit |
| + |
| +test1.exit: |
| + %retval.0.i = phi i1 [ false, %f.i ], [ true, %tailrecurse ] |
| + %brmerge = or i1 %tobool1, %retval.0.i |
| + br i1 %brmerge, label %if.end6, label %tailrecurse |
| + |
| +if.end6: |
| + ret void |
| +} |
| + |
| +declare i32 @test3() |
| -- |
| 2.23.0.rc1.153.gdeed80330f-goog |
| |