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factor some logic out of instcombine into a new SimplifyAddInst method.

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llvm-svn: 90011
This commit is contained in:
Chris Lattner 2009-11-27 17:42:22 +00:00
parent 0df78ea645
commit bdaed088ea
3 changed files with 47 additions and 17 deletions
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5
include/llvm/Analysis/InstructionSimplify.h
View File

@ -20,6 +20,11 @@ namespace llvm {
class Instruction;
class Value;
class TargetData;
/// SimplifyAddInst - Given operands for an Add, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyAddInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
const TargetData *TD = 0);
/// SimplifyAndInst - Given operands for an And, see if we can
/// fold the result. If not, this returns null.

41
lib/Analysis/InstructionSimplify.cpp
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@ -21,10 +21,38 @@
using namespace llvm;
using namespace llvm::PatternMatch;
/// SimplifyAddInst - Given operands for an Add, see if we can
/// fold the result. If not, this returns null.
Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
const TargetData *TD) {
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
Constant *Ops[] = { CLHS, CRHS };
return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(),
Ops, 2, TD);
}
// Canonicalize the constant to the RHS.
std::swap(Op0, Op1);
}
if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
// X + undef -> undef
if (isa<UndefValue>(Op1C))
return Op1C;
// X + 0 --> X
if (Op1C->isNullValue())
return Op0;
}
// FIXME: Could pull several more out of instcombine.
return 0;
}
/// SimplifyAndInst - Given operands for an And, see if we can
/// fold the result. If not, this returns null.
Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1,
const TargetData *TD) {
Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD) {
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
Constant *Ops[] = { CLHS, CRHS };
@ -83,8 +111,7 @@ Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1,
/// SimplifyOrInst - Given operands for an Or, see if we can
/// fold the result. If not, this returns null.
Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1,
const TargetData *TD) {
Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD) {
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
Constant *Ops[] = { CLHS, CRHS };
@ -142,8 +169,6 @@ Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1,
}
static const Type *GetCompareTy(Value *Op) {
return CmpInst::makeCmpResultType(Op->getType());
}
@ -327,6 +352,10 @@ Value *llvm::SimplifyInstruction(Instruction *I, const TargetData *TD) {
switch (I->getOpcode()) {
default:
return ConstantFoldInstruction(I, TD);
case Instruction::Add:
return SimplifyAddInst(I->getOperand(0), I->getOperand(1),
cast<BinaryOperator>(I)->hasNoSignedWrap(),
cast<BinaryOperator>(I)->hasNoUnsignedWrap(), TD);
case Instruction::And:
return SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD);
case Instruction::Or:

18
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -2163,8 +2163,8 @@ bool InstCombiner::WillNotOverflowSignedAdd(Value *LHS, Value *RHS) {
// Add has the property that adding any two 2's complement numbers can only
// have one carry bit which can change a sign. As such, if LHS and RHS each
// have at least two sign bits, we know that the addition of the two values will
// sign extend fine.
// have at least two sign bits, we know that the addition of the two values
// will sign extend fine.
if (ComputeNumSignBits(LHS) > 1 && ComputeNumSignBits(RHS) > 1)
return true;
@ -2184,15 +2184,12 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
bool Changed = SimplifyCommutative(I);
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
if (Value *V = SimplifyAddInst(LHS, RHS, I.hasNoSignedWrap(),
I.hasNoUnsignedWrap(), TD))
return ReplaceInstUsesWith(I, V);
if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
// X + undef -> undef
if (isa<UndefValue>(RHS))
return ReplaceInstUsesWith(I, RHS);
// X + 0 --> X
if (RHSC->isNullValue())
return ReplaceInstUsesWith(I, LHS);
if (ConstantInt *CI = dyn_cast<ConstantInt>(RHSC)) {
// X + (signbit) --> X ^ signbit
const APInt& Val = CI->getValue();
@ -4322,7 +4319,6 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
if (Value *V = SimplifyAndInst(Op0, Op1, TD))
return ReplaceInstUsesWith(I, V);
// See if we can simplify any instructions used by the instruction whose sole
// purpose is to compute bits we don't care about.