diff options
| author | Dan Gohman <gohman@apple.com> | 2009-10-26 15:32:57 +0000 |
|---|---|---|
| committer | Dan Gohman <gohman@apple.com> | 2009-10-26 15:32:57 +0000 |
| commit | a8225083ba7b2368cec0ced232e43dc77d5f6f0a (patch) | |
| tree | 1d9642aa0ac70355002c616fa9d317b6b95188f5 /lib/Transforms/Scalar/LoopStrengthReduce.cpp | |
| parent | a5dc45e3c8fa26e62b187284a240adf3879b56e2 (diff) | |
Make LSR's OptimizeShadowIV ignore induction variables with negative
strides for now, because it doesn't handle them correctly. This fixes a
miscompile of SingleSource/Benchmarks/Misc-C++/ray.
This problem was usually hidden because indvars transforms such induction
variables into negations of canonical induction variables.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85118 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Scalar/LoopStrengthReduce.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/LoopStrengthReduce.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp index 4c305aae83..e20fb16fb1 100644 --- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -2262,6 +2262,10 @@ void LoopStrengthReduce::OptimizeShadowIV(Loop *L) { if (!C) continue; + // Ignore negative constants, as the code below doesn't handle them + // correctly. TODO: Remove this restriction. + if (!C->getValue().isStrictlyPositive()) continue; + /* Add new PHINode. */ PHINode *NewPH = PHINode::Create(DestTy, "IV.S.", PH); |