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Implement InstCombine/add.ll:test21 

llvm-svn: 14443
This commit is contained in:
Chris Lattner 2004-06-27 22:51:36 +00:00
parent 0da061fa1e
commit 6e07936ed2
1 changed files with 6 additions and 1 deletions
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7
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
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@ -1520,10 +1520,15 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) {
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0)) {
switch (BO->getOpcode()) {
case Instruction::Add:
if (CI->isNullValue()) {
// Replace ((add A, B) != C) with (A != C-B) if B & C are constants.
if (ConstantInt *BOp1C = dyn_cast<ConstantInt>(BO->getOperand(1))) {
return new SetCondInst(I.getOpcode(), BO->getOperand(0),
ConstantExpr::getSub(CI, BOp1C));
} else if (CI->isNullValue()) {
// Replace ((add A, B) != 0) with (A != -B) if A or B is
// efficiently invertible, or if the add has just this one use.
Value *BOp0 = BO->getOperand(0), *BOp1 = BO->getOperand(1);
if (Value *NegVal = dyn_castNegVal(BOp1))
return new SetCondInst(I.getOpcode(), BOp0, NegVal);
else if (Value *NegVal = dyn_castNegVal(BOp0))