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[NFC] Bail early simplifying unconditional branches

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This commit is contained in:
Max Kazantsev 2020-06-15 13:58:54 +07:00
parent 6c7aebbc01
commit 60da4369a1
1 changed files with 5 additions and 1 deletions
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6
llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
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@ -2737,6 +2737,10 @@ Instruction *InstCombiner::visitReturnInst(ReturnInst &RI) {
}
Instruction *InstCombiner::visitBranchInst(BranchInst &BI) {
// Nothing to do about unconditional branches.
if (BI.isUnconditional())
return nullptr;
// Change br (not X), label True, label False to: br X, label False, True
Value *X = nullptr;
if (match(&BI, m_Br(m_Not(m_Value(X)), m_BasicBlock(), m_BasicBlock())) &&
@ -2748,7 +2752,7 @@ Instruction *InstCombiner::visitBranchInst(BranchInst &BI) {
// If the condition is irrelevant, remove the use so that other
// transforms on the condition become more effective.
if (BI.isConditional() && !isa<ConstantInt>(BI.getCondition()) &&
if (!isa<ConstantInt>(BI.getCondition()) &&
BI.getSuccessor(0) == BI.getSuccessor(1))
return replaceOperand(
BI, 0, ConstantInt::getFalse(BI.getCondition()->getType()));