diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index fd2b68a9ecd..e9f3458be98 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -1277,6 +1277,15 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, return Res; } } + + // X & -C == -C -> X > u ~C + // X & -C != -C -> X <= u ~C + // iff C is a power of 2 + if (ICI.isEquality() && RHS == LHSI->getOperand(1) && (-RHSV).isPowerOf2()) + return new ICmpInst( + ICI.getPredicate() == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_UGT + : ICmpInst::ICMP_ULE, + LHSI->getOperand(0), SubOne(RHS)); break; case Instruction::Or: { |
