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implement InstCombine/shift-simplify.ll by transforming:

Browse Source 
(X >> Z) op (Y >> Z)  -> (X op Y) >> Z

for all shifts and all ops={and/or/xor}.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31729 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-11-14 07:46:50 +00:00
parent 9961cf1fed
commit e511b74f4a
1 changed files with 46 additions and 3 deletions
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49
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -3310,9 +3310,9 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
}
// fold (and (cast A), (cast B)) -> (cast (and A, B))
if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
const Type *SrcTy = Op0C->getOperand(0)->getType();
if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
if (CastInst *Op1C = dyn_cast<CastInst>(Op1)) {
if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
const Type *SrcTy = Op0C->getOperand(0)->getType();
if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegral() &&
// Only do this if the casts both really cause code to be generated.
ValueRequiresCast(Op0C->getOperand(0), I.getType(), TD) &&
@ -3323,6 +3323,21 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
InsertNewInstBefore(NewOp, I);
return new CastInst(NewOp, I.getType());
}
}
}
// (X >> Z) & (Y >> Z) -> (X&Y) >> Z for all shifts.
if (ShiftInst *SI1 = dyn_cast<ShiftInst>(Op1)) {
if (ShiftInst *SI0 = dyn_cast<ShiftInst>(Op0))
if (SI0->getOpcode() == SI1->getOpcode() &&
SI0->getOperand(1) == SI1->getOperand(1) &&
(SI0->hasOneUse() || SI1->hasOneUse())) {
Instruction *NewOp =
InsertNewInstBefore(BinaryOperator::createAnd(SI0->getOperand(0),
SI1->getOperand(0),
SI0->getName()), I);
return new ShiftInst(SI1->getOpcode(), NewOp, SI1->getOperand(1));
}
}
return Changed ? &I : 0;
@ -3567,6 +3582,20 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
}
}
}
// (X >> Z) | (Y >> Z) -> (X|Y) >> Z for all shifts.
if (ShiftInst *SI1 = dyn_cast<ShiftInst>(Op1)) {
if (ShiftInst *SI0 = dyn_cast<ShiftInst>(Op0))
if (SI0->getOpcode() == SI1->getOpcode() &&
SI0->getOperand(1) == SI1->getOperand(1) &&
(SI0->hasOneUse() || SI1->hasOneUse())) {
Instruction *NewOp =
InsertNewInstBefore(BinaryOperator::createOr(SI0->getOperand(0),
SI1->getOperand(0),
SI0->getName()), I);
return new ShiftInst(SI1->getOpcode(), NewOp, SI1->getOperand(1));
}
}
if (match(Op0, m_Not(m_Value(A)))) { // ~A | Op1
if (A == Op1) // ~A | A == -1
@ -3879,6 +3908,20 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
return new CastInst(NewOp, I.getType());
}
}
// (X >> Z) ^ (Y >> Z) -> (X^Y) >> Z for all shifts.
if (ShiftInst *SI1 = dyn_cast<ShiftInst>(Op1)) {
if (ShiftInst *SI0 = dyn_cast<ShiftInst>(Op0))
if (SI0->getOpcode() == SI1->getOpcode() &&
SI0->getOperand(1) == SI1->getOperand(1) &&
(SI0->hasOneUse() || SI1->hasOneUse())) {
Instruction *NewOp =
InsertNewInstBefore(BinaryOperator::createXor(SI0->getOperand(0),
SI1->getOperand(0),
SI0->getName()), I);
return new ShiftInst(SI1->getOpcode(), NewOp, SI1->getOperand(1));
}
}
return Changed ? &I : 0;
}