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| 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 | d632f89596f77e0df731280adedf3ac7e8fd1d4f (patch) | |
| tree | acabf75e8fbc678fa3f1735d6acf2f05fda2c732 /llvm/lib/Transforms | |
| parent | 4302824fe26039e00cf48da39f1c799d3c1de368 (diff) | |
| download | bcm5719-llvm-d632f89596f77e0df731280adedf3ac7e8fd1d4f.tar.gz bcm5719-llvm-d632f89596f77e0df731280adedf3ac7e8fd1d4f.zip | |
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.
llvm-svn: 85118
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp index 4c305aae832..e20fb16fb16 100644 --- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/llvm/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); |
