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| author | Andrew Trick <atrick@apple.com> | 2011-11-17 23:36:35 +0000 |
|---|---|---|
| committer | Andrew Trick <atrick@apple.com> | 2011-11-17 23:36:35 +0000 |
| commit | 4f3052403ca5ea9542a118c2e54ff9c82038f41c (patch) | |
| tree | 1dd30660130db7eec9772488e057b352767226cb /lib/Transforms/Utils/SimplifyIndVar.cpp | |
| parent | 7cf2a04361e8613264498e50babe52d65c070473 (diff) | |
| download | llvm-4f3052403ca5ea9542a118c2e54ff9c82038f41c.tar.gz llvm-4f3052403ca5ea9542a118c2e54ff9c82038f41c.tar.bz2 llvm-4f3052403ca5ea9542a118c2e54ff9c82038f41c.tar.xz | |
Fix an overly general check in SimplifyIndvar to handle useless phi cycles.
The right way to check for a binary operation is
cast<BinaryOperator>. The original check: cast<Instruction> &&
numOperands() == 2 would match phi "instructions", leading to an
infinite loop in extreme corner case: a useless phi with operands
[self, constant] that prior optimization passes failed to remove,
being used in the loop by another useless phi, in turn being used by an
lshr or udiv.
Fixes PR11350: runaway iteration assertion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144935 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Utils/SimplifyIndVar.cpp')
| -rw-r--r-- | lib/Transforms/Utils/SimplifyIndVar.cpp | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/lib/Transforms/Utils/SimplifyIndVar.cpp b/lib/Transforms/Utils/SimplifyIndVar.cpp index 76289c055b..6732a789d5 100644 --- a/lib/Transforms/Utils/SimplifyIndVar.cpp +++ b/lib/Transforms/Utils/SimplifyIndVar.cpp @@ -107,8 +107,8 @@ Value *SimplifyIndvar::foldIVUser(Instruction *UseInst, Instruction *IVOperand) // Attempt to fold a binary operator with constant operand. // e.g. ((I + 1) >> 2) => I >> 2 - if (IVOperand->getNumOperands() != 2 || - !isa<ConstantInt>(IVOperand->getOperand(1))) + if (!isa<BinaryOperator>(IVOperand) + || !isa<ConstantInt>(IVOperand->getOperand(1))) return 0; IVSrc = IVOperand->getOperand(0); |