diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index dc071380435..978b2e95ccc 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -1927,21 +1927,6 @@ static bool isSignBit(ConstantInt *CI) { return (CI->getZExtValue() & (~0ULL >> (64-NumBits))) == (1ULL << (NumBits-1)); } -/// RemoveNoopCast - Strip off nonconverting casts from the value. -/// -static Value *RemoveNoopCast(Value *V) { - if (CastInst *CI = dyn_cast(V)) { - const Type *CTy = CI->getType(); - const Type *OpTy = CI->getOperand(0)->getType(); - if (CTy->isInteger() && OpTy->isInteger()) { - if (CTy->getPrimitiveSizeInBits() == OpTy->getPrimitiveSizeInBits()) - return RemoveNoopCast(CI->getOperand(0)); - } else if (isa(CTy) && isa(OpTy)) - return RemoveNoopCast(CI->getOperand(0)); - } - return V; -} - Instruction *InstCombiner::visitSub(BinaryOperator &I) { Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); @@ -1967,21 +1952,17 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) { if (match(Op1, m_Not(m_Value(X)))) return BinaryOperator::createAdd(X, ConstantExpr::getAdd(C, ConstantInt::get(I.getType(), 1))); - // -((uint)X >> 31) -> ((int)X >> 31) - // -((int)X >> 31) -> ((uint)X >> 31) + // -(X >>u 31) -> (X >>s 31) + // -(X >>s 31) -> (X >>u 31) if (C->isNullValue()) { - Value *NoopCastedRHS = RemoveNoopCast(Op1); - if (ShiftInst *SI = dyn_cast(NoopCastedRHS)) + if (ShiftInst *SI = dyn_cast(Op1)) if (SI->getOpcode() == Instruction::LShr) { if (ConstantInt *CU = dyn_cast(SI->getOperand(1))) { // Check to see if we are shifting out everything but the sign bit. if (CU->getZExtValue() == SI->getType()->getPrimitiveSizeInBits()-1) { // Ok, the transformation is safe. Insert AShr. - // FIXME: Once integer types are signless, this cast should be - // removed. - Value *ShiftOp = SI->getOperand(0); - return new ShiftInst(Instruction::AShr, ShiftOp, CU, + return new ShiftInst(Instruction::AShr, SI->getOperand(0), CU, SI->getName()); } } @@ -1991,7 +1972,6 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) { // Check to see if we are shifting out everything but the sign bit. if (CU->getZExtValue() == SI->getType()->getPrimitiveSizeInBits()-1) { - // Ok, the transformation is safe. Insert LShr. return new ShiftInst(Instruction::LShr, SI->getOperand(0), CU, SI->getName()); @@ -7664,28 +7644,14 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { for (unsigned i = 1, e = GEP.getNumOperands(); i != e; ++i, ++GTI) if (isa(*GTI)) { if (CastInst *CI = dyn_cast(GEP.getOperand(i))) { - Value *Src = CI->getOperand(0); - const Type *SrcTy = Src->getType(); - const Type *DestTy = CI->getType(); - if (Src->getType()->isInteger()) { - if (SrcTy->getPrimitiveSizeInBits() == - DestTy->getPrimitiveSizeInBits()) { - // We can always eliminate a cast from ulong or long to the other. - // We can always eliminate a cast from uint to int or the other on - // 32-bit pointer platforms. - if (DestTy->getPrimitiveSizeInBits() >= TD->getPointerSizeInBits()){ - MadeChange = true; - GEP.setOperand(i, Src); - } - } else if (SrcTy->getPrimitiveSizeInBits() < - DestTy->getPrimitiveSizeInBits() && - SrcTy->getPrimitiveSizeInBits() == 32) { - // We can eliminate a cast from [u]int to [u]long iff the target - // is a 32-bit pointer target. - if (SrcTy->getPrimitiveSizeInBits() >= TD->getPointerSizeInBits()) { - MadeChange = true; - GEP.setOperand(i, Src); - } + if (CI->getOpcode() == Instruction::ZExt || + CI->getOpcode() == Instruction::SExt) { + const Type *SrcTy = CI->getOperand(0)->getType(); + // We can eliminate a cast from i32 to i64 iff the target + // is a 32-bit pointer target. + if (SrcTy->getPrimitiveSizeInBits() >= TD->getPointerSizeInBits()) { + MadeChange = true; + GEP.setOperand(i, CI->getOperand(0)); } } }