diff options
Diffstat (limited to 'lib/Transforms/Scalar/InstructionCombining.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 4161724225..37ba949a2e 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -837,7 +837,6 @@ Instruction *InstCombiner::visitDiv(BinaryOperator &I) { if (Instruction *LHS = dyn_cast<Instruction>(I.getOperand(0))) if (LHS->getOpcode() == Instruction::Div) if (ConstantInt *LHSRHS = dyn_cast<ConstantInt>(LHS->getOperand(1))) { - std::cerr << "DIV: " << *LHS << " : " << I; // (X / C1) / C2 -> X / (C1*C2) return BinaryOperator::createDiv(LHS->getOperand(0), ConstantExpr::getMul(RHS, LHSRHS)); @@ -1764,6 +1763,44 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) { } break; + case Instruction::Cast: { // (setcc (cast X to larger), CI) + const Type *SrcTy = LHSI->getOperand(0)->getType(); + if (SrcTy->isIntegral() && LHSI->getType()->isIntegral()) { + unsigned SrcBits = SrcTy->getPrimitiveSize(); + if (SrcTy == Type::BoolTy) SrcBits = 1; + unsigned DestBits = LHSI->getType()->getPrimitiveSize(); + if (LHSI->getType() == Type::BoolTy) DestBits = 1; + if (SrcBits < DestBits) { + // 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"); + 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::SetLE: + return ReplaceInstUsesWith(I, ConstantExpr::getSetLE(Max, CI)); + case Instruction::SetGT: + return ReplaceInstUsesWith(I, ConstantExpr::getSetGT(Min, CI)); + case Instruction::SetGE: + return ReplaceInstUsesWith(I, ConstantExpr::getSetGE(Min, CI)); + } + } + + return new SetCondInst(I.getOpcode(), LHSI->getOperand(0), + ConstantExpr::getCast(CI, SrcTy)); + } + } + break; + } case Instruction::Shl: // (setcc (shl X, ShAmt), CI) if (ConstantUInt *ShAmt = dyn_cast<ConstantUInt>(LHSI->getOperand(1))) { switch (I.getOpcode()) { |