diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index f8f0573395..9274a4259c 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -2024,29 +2024,38 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) { if (SrcTy == Type::BoolTy) SrcBits = 1; unsigned DestBits = LHSI->getType()->getPrimitiveSize()*8; if (LHSI->getType() == Type::BoolTy) DestBits = 1; - if (SrcBits < DestBits) { + if (SrcBits < DestBits && + // FIXME: Reenable the code below for < and >. However, we have + // to handle the cases when the source of the cast and the dest of + // the cast have different signs. e.g: + // (cast sbyte %X to uint) >u 255U -> X <s (sbyte)0 + (I.getOpcode() == Instruction::SetEQ || + I.getOpcode() == Instruction::SetNE)) { // Check to see if the comparison is always true or false. Constant *NewCst = ConstantExpr::getCast(CI, SrcTy); if (ConstantExpr::getCast(NewCst, LHSI->getType()) != CI) { - Constant *Min = ConstantIntegral::getMinValue(SrcTy); - Constant *Max = ConstantIntegral::getMaxValue(SrcTy); - Min = ConstantExpr::getCast(Min, LHSI->getType()); - Max = ConstantExpr::getCast(Max, LHSI->getType()); switch (I.getOpcode()) { default: assert(0 && "unknown integer comparison"); +#if 0 + case Instruction::SetLT: { + Constant *Max = ConstantIntegral::getMaxValue(SrcTy); + Max = ConstantExpr::getCast(Max, LHSI->getType()); + return ReplaceInstUsesWith(I, ConstantExpr::getSetLT(Max, CI)); + } + case Instruction::SetGT: { + Constant *Min = ConstantIntegral::getMinValue(SrcTy); + Min = ConstantExpr::getCast(Min, LHSI->getType()); + return ReplaceInstUsesWith(I, ConstantExpr::getSetGT(Min, CI)); + } +#endif case Instruction::SetEQ: return ReplaceInstUsesWith(I, ConstantBool::False); case Instruction::SetNE: return ReplaceInstUsesWith(I, ConstantBool::True); - case Instruction::SetLT: - return ReplaceInstUsesWith(I, ConstantExpr::getSetLT(Max, CI)); - case Instruction::SetGT: - return ReplaceInstUsesWith(I, ConstantExpr::getSetGT(Min, CI)); } } - return new SetCondInst(I.getOpcode(), LHSI->getOperand(0), - ConstantExpr::getCast(CI, SrcTy)); + return new SetCondInst(I.getOpcode(), LHSI->getOperand(0), NewCst); } } break; |