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Implement test/Regression/Transforms/InstCombine/canonicalize_branch.ll

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This is a really minor thing, but might help out the 'switch statement induction'
code in simplifycfg.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11900 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-02-27 06:27:46 +00:00
parent f7b0041fb5
commit a0ebcebc06
1 changed files with 23 additions and 1 deletions
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24
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -2343,7 +2343,7 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
Instruction *InstCombiner::visitBranchInst(BranchInst &BI) {
// Change br (not X), label True, label False to: br X, label False, True
if (BI.isConditional() && !isa<Constant>(BI.getCondition()))
if (BI.isConditional() && !isa<Constant>(BI.getCondition())) {
if (Value *V = dyn_castNotVal(BI.getCondition())) {
BasicBlock *TrueDest = BI.getSuccessor(0);
BasicBlock *FalseDest = BI.getSuccessor(1);
@ -2352,7 +2352,29 @@ Instruction *InstCombiner::visitBranchInst(BranchInst &BI) {
BI.setSuccessor(0, FalseDest);
BI.setSuccessor(1, TrueDest);
return &BI;
} else if (SetCondInst *I = dyn_cast<SetCondInst>(BI.getCondition())) {
// Cannonicalize setne -> seteq
if ((I->getOpcode() == Instruction::SetNE ||
I->getOpcode() == Instruction::SetLE ||
I->getOpcode() == Instruction::SetGE) && I->hasOneUse()) {
std::string Name = I->getName(); I->setName("");
Instruction::BinaryOps NewOpcode =
SetCondInst::getInverseCondition(I->getOpcode());
Value *NewSCC = BinaryOperator::create(NewOpcode, I->getOperand(0),
I->getOperand(1), Name, I);
BasicBlock *TrueDest = BI.getSuccessor(0);
BasicBlock *FalseDest = BI.getSuccessor(1);
// Swap Destinations and condition...
BI.setCondition(NewSCC);
BI.setSuccessor(0, FalseDest);
BI.setSuccessor(1, TrueDest);
removeFromWorkList(I);
I->getParent()->getInstList().erase(I);
WorkList.push_back(cast<Instruction>(NewSCC));
return &BI;
}
}
}
return 0;
}