diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index 5ca0ed25675..a855a0dd2d1 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -3052,26 +3052,27 @@ Instruction *InstCombiner::foldICmpBinOp(ICmpInst &I) { } break; } - case Instruction::Mul: + case Instruction::Mul: { if (!I.isEquality()) break; - if (ConstantInt *CI = dyn_cast<ConstantInt>(BO0->getOperand(1))) { - // a * Cst icmp eq/ne b * Cst --> a & Mask icmp b & Mask - // Mask = -1 >> count-trailing-zeros(Cst). - if (!CI->isZero() && !CI->isOne()) { - const APInt &AP = CI->getValue(); - ConstantInt *Mask = ConstantInt::get( - I.getContext(), - APInt::getLowBitsSet(AP.getBitWidth(), - AP.getBitWidth() - AP.countTrailingZeros())); + const APInt *C; + if (match(BO0->getOperand(1), m_APInt(C))) { + // icmp eq/ne (X * C), (Y * C) --> icmp (X & Mask), (Y & Mask) + // Mask = -1 >> count-trailing-zeros(C). + if (*C != 0 && *C != 1) { + // FIXME: If trailing zeros is 0, don't bother creating Mask. + Constant *Mask = ConstantInt::get( + BO0->getType(), + APInt::getLowBitsSet(C->getBitWidth(), + C->getBitWidth() - C->countTrailingZeros())); Value *And1 = Builder->CreateAnd(BO0->getOperand(0), Mask); Value *And2 = Builder->CreateAnd(BO1->getOperand(0), Mask); return new ICmpInst(Pred, And1, And2); } } break; - + } case Instruction::UDiv: case Instruction::LShr: if (I.isSigned() || !BO0->isExact() || !BO1->isExact()) |
