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inline the 'AddRHS' transformation, simplifying things significantly.

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Eliminate the 'AddMaskingAnd' transformation, it is redundant with this
more general code right below it:
  // A+B --> A|B iff A and B have no bits set in common.

llvm-svn: 92693
This commit is contained in:
Chris Lattner 2010-01-05 06:29:13 +00:00
parent 17a2db8444
commit 1e57d0e7e3
1 changed files with 4 additions and 39 deletions
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43
lib/Transforms/InstCombine/InstructionCombining.cpp
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@ -305,36 +305,6 @@ static Instruction *AssociativeOpt(BinaryOperator &Root, const Functor &F) {
return 0;
}
namespace {
// AddRHS - Implements: X + X --> X << 1
struct AddRHS {
Value *RHS;
explicit AddRHS(Value *rhs) : RHS(rhs) {}
bool shouldApply(Value *LHS) const { return LHS == RHS; }
Instruction *apply(BinaryOperator &Add) const {
return BinaryOperator::CreateShl(Add.getOperand(0),
ConstantInt::get(Add.getType(), 1));
}
};
// AddMaskingAnd - Implements (A & C1)+(B & C2) --> (A & C1)|(B & C2)
// iff C1&C2 == 0
struct AddMaskingAnd {
Constant *C2;
explicit AddMaskingAnd(Constant *c) : C2(c) {}
bool shouldApply(Value *LHS) const {
ConstantInt *C1;
return match(LHS, m_And(m_Value(), m_ConstantInt(C1))) &&
ConstantExpr::getAnd(C1, C2)->isNullValue();
}
Instruction *apply(BinaryOperator &Add) const {
return BinaryOperator::CreateOr(Add.getOperand(0), Add.getOperand(1));
}
};
}
static Value *FoldOperationIntoSelectOperand(Instruction &I, Value *SO,
InstCombiner *IC) {
if (CastInst *CI = dyn_cast<CastInst>(&I))
@ -622,10 +592,10 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
if (I.getType() == Type::getInt1Ty(I.getContext()))
return BinaryOperator::CreateXor(LHS, RHS);
// X + X --> X << 1
if (I.getType()->isInteger()) {
if (Instruction *Result = AssociativeOpt(I, AddRHS(RHS)))
return Result;
// X + X --> X << 1
if (LHS == RHS)
return BinaryOperator::CreateShl(LHS, ConstantInt::get(I.getType(), 1));
if (Instruction *RHSI = dyn_cast<Instruction>(RHS)) {
if (RHSI->getOpcode() == Instruction::Sub)
@ -679,11 +649,6 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType()));
// (A & C1)+(B & C2) --> (A & C1)|(B & C2) iff C1&C2 == 0
if (match(RHS, m_And(m_Value(), m_ConstantInt(C2))))
if (Instruction *R = AssociativeOpt(I, AddMaskingAnd(C2)))
return R;
// A+B --> A|B iff A and B have no bits set in common.
if (const IntegerType *IT = dyn_cast<IntegerType>(I.getType())) {
APInt Mask = APInt::getAllOnesValue(IT->getBitWidth());
@ -736,7 +701,7 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
if (Anded == CRHS) {
// See if all bits from the first bit set in the Add RHS up are included
// in the mask. First, get the rightmost bit.
const APInt& AddRHSV = CRHS->getValue();
const APInt &AddRHSV = CRHS->getValue();
// Form a mask of all bits from the lowest bit added through the top.
APInt AddRHSHighBits(~((AddRHSV & -AddRHSV)-1));