Implement Transforms/InstCombine/and.ll:test17, a common case that

occurs due to unordered comparison macros in math.h


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14221 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-06-18 06:07:51 +00:00
parent b80e3ada7b
commit 5b62aa743d

View File

@ -1130,6 +1130,9 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
Value *Op0NotVal = dyn_castNotVal(Op0);
Value *Op1NotVal = dyn_castNotVal(Op1);
if (Op0NotVal == Op1 || Op1NotVal == Op0) // A & ~A == ~A & A == 0
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
// (~A & ~B) == (~(A | B)) - Demorgan's Law
if (Op0NotVal && Op1NotVal && isOnlyUse(Op0) && isOnlyUse(Op1)) {
Instruction *Or = BinaryOperator::createOr(Op0NotVal, Op1NotVal,
@ -1138,9 +1141,6 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
return BinaryOperator::createNot(Or);
}
if (Op0NotVal == Op1 || Op1NotVal == Op0) // A & ~A == ~A & A == 0
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
// (setcc1 A, B) & (setcc2 A, B) --> (setcc3 A, B)
if (SetCondInst *RHS = dyn_cast<SetCondInst>(I.getOperand(1)))
if (Instruction *R = AssociativeOpt(I, FoldSetCCLogical(*this, RHS)))
@ -1271,6 +1271,18 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
ConstantInt::get(I.getType(), 1));
return BinaryOperator::createAdd(Op0I->getOperand(1), ConstantRHS);
}
// ~(~X & Y) --> (X | ~Y)
if (Op0I->getOpcode() == Instruction::And && RHS->isAllOnesValue()) {
if (dyn_castNotVal(Op0I->getOperand(1))) Op0I->swapOperands();
if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) {
Instruction *NotY =
BinaryOperator::createNot(Op0I->getOperand(1),
Op0I->getOperand(1)->getName()+".not");
InsertNewInstBefore(NotY, I);
return BinaryOperator::createOr(Op0NotVal, NotY);
}
}
if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1)))
switch (Op0I->getOpcode()) {