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Get rid of a several dozen more and instructions in specint.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19786 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-01-23 20:26:55 +00:00
parent da7e70e058
commit ad1e302723
1 changed files with 36 additions and 5 deletions
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41
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -1298,6 +1298,14 @@ static bool MaskedValueIsZero(Value *V, ConstantIntegral *Mask) {
if (ConstantExpr::getAnd(CI, Mask)->isNullValue())
return true;
break;
case Instruction::Or:
// If the LHS and the RHS are MaskedValueIsZero, the result is also zero.
return MaskedValueIsZero(I->getOperand(1), Mask) &&
MaskedValueIsZero(I->getOperand(0), Mask);
case Instruction::Select:
// If the T and F values are MaskedValueIsZero, the result is also zero.
return MaskedValueIsZero(I->getOperand(2), Mask) &&
MaskedValueIsZero(I->getOperand(1), Mask);
case Instruction::Cast: {
const Type *SrcTy = I->getOperand(0)->getType();
if (SrcTy->isIntegral()) {
@ -1535,9 +1543,9 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
if (Op0 == Op1)
return ReplaceInstUsesWith(I, Op1);
// and X, -1 == X
if (ConstantIntegral *AndRHS = dyn_cast<ConstantIntegral>(Op1)) {
if (AndRHS->isAllOnesValue()) // and X, -1 == X
// and X, -1 == X
if (AndRHS->isAllOnesValue())
return ReplaceInstUsesWith(I, Op0);
if (MaskedValueIsZero(Op0, AndRHS)) // LHS & RHS == 0
@ -1545,9 +1553,10 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
// If the mask is not masking out any bits, there is no reason to do the
// and in the first place.
if (MaskedValueIsZero(Op0,
cast<ConstantIntegral>(ConstantExpr::getNot(AndRHS))))
return ReplaceInstUsesWith(I, Op0);
ConstantIntegral *NotAndRHS =
cast<ConstantIntegral>(ConstantExpr::getNot(AndRHS));
if (MaskedValueIsZero(Op0, NotAndRHS))
return ReplaceInstUsesWith(I, Op0);
// Optimize a variety of ((val OP C1) & C2) combinations...
if (isa<BinaryOperator>(Op0) || isa<ShiftInst>(Op0)) {
@ -1563,6 +1572,28 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
return BinaryOperator::createAnd(Op0RHS, AndRHS);
if (MaskedValueIsZero(Op0RHS, AndRHS))
return BinaryOperator::createAnd(Op0LHS, AndRHS);
// If the mask is only needed on one incoming arm, push it up.
if (Op0I->hasOneUse()) {
if (MaskedValueIsZero(Op0LHS, NotAndRHS)) {
// Not masking anything out for the LHS, move to RHS.
Instruction *NewRHS = BinaryOperator::createAnd(Op0RHS, AndRHS,
Op0RHS->getName()+".masked");
InsertNewInstBefore(NewRHS, I);
return BinaryOperator::create(
cast<BinaryOperator>(Op0I)->getOpcode(), Op0LHS, NewRHS);
}
if (!isa<Constant>(NotAndRHS) &&
MaskedValueIsZero(Op0RHS, NotAndRHS)) {
// Not masking anything out for the RHS, move to LHS.
Instruction *NewLHS = BinaryOperator::createAnd(Op0LHS, AndRHS,
Op0LHS->getName()+".masked");
InsertNewInstBefore(NewLHS, I);
return BinaryOperator::create(
cast<BinaryOperator>(Op0I)->getOpcode(), NewLHS, Op0RHS);
}
}
break;
case Instruction::And:
// (X & V) & C2 --> 0 iff (V & C2) == 0