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Be more careful about the order we put stuff onto the worklist. This allow us to

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bool %le(int %A, int %B) {
        %c1 = setgt int %A, %B
        %tmp = select bool %c1, int 1, int 0
        %c2 = setlt int %A, %B
        %result = select bool %c2, int -1, int %tmp
        %c3 = setle int %result, 0
        ret bool %c3
}

into:

bool %le(int %A, int %B) {
        %c3 = setle int %A, %B          ; <bool> [#uses=1]
        ret bool %c3
}

which is handy, because the Java FE makes these sequences all over the place.

This is tested as: test/Regression/Transforms/InstCombine/JavaCompare.ll

llvm-svn: 14086
This commit is contained in:
Chris Lattner 2004-06-09 05:08:07 +00:00
parent 7a4fdfb460
commit 90a2bbc74c
1 changed files with 19 additions and 19 deletions
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38
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -704,7 +704,8 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) {
(Op1I->getOperand(0) == Op0 || Op1I->getOperand(1) == Op0)) {
Value *OtherOp = Op1I->getOperand(Op1I->getOperand(0) == Op0);
Instruction *NewNot = BinaryOperator::createNot(OtherOp, "B.not", &I);
Value *NewNot =
InsertNewInstBefore(BinaryOperator::createNot(OtherOp, "B.not"), I);
return BinaryOperator::create(Instruction::And, Op0, NewNot);
}
@ -1249,10 +1250,9 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
// (~A | ~B) == (~(A & B)) - Demorgan's Law
if (Op0NotVal && Op1NotVal && isOnlyUse(Op0) && isOnlyUse(Op1)) {
Instruction *And = BinaryOperator::create(Instruction::And, Op0NotVal,
Op1NotVal,I.getName()+".demorgan",
&I);
WorkList.push_back(And);
Value *And = InsertNewInstBefore(
BinaryOperator::create(Instruction::And, Op0NotVal,
Op1NotVal,I.getName()+".demorgan"), I);
return BinaryOperator::createNot(And);
}
@ -1374,8 +1374,8 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
if (Op0I->getOperand(0) == Op1) // (B|A)^B == (A|B)^B
cast<BinaryOperator>(Op0I)->swapOperands();
if (Op0I->getOperand(1) == Op1) { // (A|B)^B == A & ~B
Value *NotB = BinaryOperator::createNot(Op1, Op1->getName()+".not", &I);
WorkList.push_back(cast<Instruction>(NotB));
Value *NotB = InsertNewInstBefore(BinaryOperator::createNot(Op1,
Op1->getName()+".not"), I);
return BinaryOperator::create(Instruction::And, Op0I->getOperand(0),
NotB);
}
@ -1508,7 +1508,6 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) {
return &I;
}
}
} else if (SelectInst *SI = dyn_cast<SelectInst>(LHSI)) {
// If either operand of the select is a constant, we can fold the
// comparison into the select arms, which will cause one to be
@ -3051,9 +3050,12 @@ bool InstCombiner::runOnFunction(Function &F) {
DEBUG(std::cerr << "IC: Old = " << *I
<< " New = " << *Result);
// Instructions can end up on the worklist more than once. Make sure
// we do not process an instruction that has been deleted.
removeFromWorkList(I);
// Everything uses the new instruction now.
I->replaceAllUsesWith(Result);
// Push the new instruction and any users onto the worklist.
WorkList.push_back(Result);
AddUsersToWorkList(*Result);
// Move the name to the new instruction first...
std::string OldName = I->getName(); I->setName("");
@ -3069,8 +3071,9 @@ bool InstCombiner::runOnFunction(Function &F) {
if (Instruction *OpI = dyn_cast<Instruction>(I->getOperand(i)))
WorkList.push_back(OpI);
// Everything uses the new instruction now...
I->replaceAllUsesWith(Result);
// Instructions can end up on the worklist more than once. Make sure
// we do not process an instruction that has been deleted.
removeFromWorkList(I);
// Erase the old instruction.
InstParent->getInstList().erase(I);
@ -3090,14 +3093,11 @@ bool InstCombiner::runOnFunction(Function &F) {
// occurrances of this instruction.
removeFromWorkList(I);
I->getParent()->getInstList().erase(I);
Result = 0;
} else {
WorkList.push_back(Result);
AddUsersToWorkList(*Result);
}
}
if (Result) {
WorkList.push_back(Result);
AddUsersToWorkList(*Result);
}
Changed = true;
}
}