replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Revert this transform. It was causing some dramatic slowdowns in a few tests. See PR3266. 

llvm-svn: 61623
This commit is contained in:
Bill Wendling 2009-01-04 06:19:11 +00:00
parent a0979b24d3
commit 0c04f9fdc3
1 changed files with 0 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -4880,37 +4880,6 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
if (FCmpInst *FCI = dyn_cast<FCmpInst>(Op0))
return new FCmpInst(FCI->getInversePredicate(),
FCI->getOperand(0), FCI->getOperand(1));
// xor (or (cmp x,m),(cmp y,n)),true --> and (!cmp x,m),(!cmp y,n)
//
// Proof:
// Let A = (cmp x,m)
// Let B = (cmp y,n)
// Let C = (or A, B)
// C true implies that either A, B, or both are true.
//
// (xor C, true) is true only if C is false. We can then apply de
// Morgan's law. QED.
BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0);
if (Op0I) {
Value *A, *B;
if (match(Op0I, m_Or(m_Value(A), m_Value(B)))) {
ICmpInst *AOp = dyn_cast<ICmpInst>(A);
ICmpInst *BOp = dyn_cast<ICmpInst>(B);
if (AOp && BOp) {
ICmpInst *NewA = new ICmpInst(AOp->getInversePredicate(),
AOp->getOperand(0),
AOp->getOperand(1));
InsertNewInstBefore(NewA, I);
ICmpInst *NewB = new ICmpInst(BOp->getInversePredicate(),
BOp->getOperand(0),
BOp->getOperand(1));
InsertNewInstBefore(NewB, I);
return BinaryOperator::CreateAnd(NewA, NewB);
}
}
}
}
// fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp).