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[CorrelatedValuePropagation] Remove redundant if statement in processSelect() 

This statement

    if (ReplaceWith == S) ReplaceWith = UndefValue::get(S->getType());

is introduced in https://reviews.llvm.org/rG35609d97ae89b8e13f40f4e6b9b056954f8baa83
to fix a case where unreachable code can cause select instruction
simplification to fail. In https://reviews.llvm.org/rGd10480657527ffb44ea213460fb3676a6b1300aa,
we begin to perform a depth-first walk of basic blocks. This means
we will not visit unreachable blocks. So we do not need this the
special check any more.

Differential Revision: https://reviews.llvm.org/D76753
This commit is contained in:
Enna1 2020-03-28 17:59:22 +01:00 committed by Nikita Popov
parent e6112a56dd
commit 03bc311a16
1 changed files with 2 additions and 6 deletions
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8
llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
View File

@ -125,7 +125,7 @@ Pass *llvm::createCorrelatedValuePropagationPass() {
static bool processSelect(SelectInst *S, LazyValueInfo *LVI) {
if (S->getType()->isVectorTy()) return false;
if (isa<Constant>(S->getOperand(0))) return false;
if (isa<Constant>(S->getCondition())) return false;
Constant *C = LVI->getConstant(S->getCondition(), S->getParent(), S);
if (!C) return false;
@ -133,11 +133,7 @@ static bool processSelect(SelectInst *S, LazyValueInfo *LVI) {
ConstantInt *CI = dyn_cast<ConstantInt>(C);
if (!CI) return false;
Value *ReplaceWith = S->getTrueValue();
Value *Other = S->getFalseValue();
if (!CI->isOne()) std::swap(ReplaceWith, Other);
if (ReplaceWith == S) ReplaceWith = UndefValue::get(S->getType());
Value *ReplaceWith = CI->isOne() ? S->getTrueValue() : S->getFalseValue();
S->replaceAllUsesWith(ReplaceWith);
S->eraseFromParent();