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| author | Justin Bogner <mail@justinbogner.com> | 2016-02-25 01:02:18 +0000 |
|---|---|---|
| committer | Justin Bogner <mail@justinbogner.com> | 2016-02-25 01:02:18 +0000 |
| commit | 08154bf3d2539a3a74af6a4a3822c566ab329b14 (patch) | |
| tree | d48d7d9d31b31ed35bd34cd4fe993d6ebb52f668 /llvm/lib/IR/ConstantFold.cpp | |
| parent | 479d545ca2d499f791a84722e0c84f1aa55428b8 (diff) | |
| download | bcm5719-llvm-08154bf3d2539a3a74af6a4a3822c566ab329b14.tar.gz bcm5719-llvm-08154bf3d2539a3a74af6a4a3822c566ab329b14.zip | |
IR: Make the X / undef -> undef fold match the comment
The constant folding for sdiv and udiv has a big discrepancy between the
comments and the code, which looks like a typo. Currently, we're folding
X / undef pretty inconsistently:
0 / undef -> undef
C / undef -> 0
undef / undef -> 0
Whereas the comments state we do X / undef -> undef. The logic that
returns zero is actually commented as doing undef / X -> 0, despite that
the LHS isn't undef in many of the cases that hit it.
llvm-svn: 261813
Diffstat (limited to 'llvm/lib/IR/ConstantFold.cpp')
| -rw-r--r-- | llvm/lib/IR/ConstantFold.cpp | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/llvm/lib/IR/ConstantFold.cpp b/llvm/lib/IR/ConstantFold.cpp index 00ff9788a9c..aea8308e9c6 100644 --- a/llvm/lib/IR/ConstantFold.cpp +++ b/llvm/lib/IR/ConstantFold.cpp @@ -948,7 +948,7 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, case Instruction::SDiv: case Instruction::UDiv: // X / undef -> undef - if (match(C1, m_Zero())) + if (isa<UndefValue>(C2)) return C2; // undef / 0 -> undef // undef / 1 -> undef |
