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NewGVN: Detect copies through predicateinfo 

llvm-svn: 312508
This commit is contained in:
Daniel Berlin 2017-09-05 02:17:41 +00:00
parent 4ad7e8d263
commit 1a58258232
1 changed files with 12 additions and 1 deletions
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13
llvm/lib/Transforms/Scalar/NewGVN.cpp
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@ -850,6 +850,17 @@ void NewGVN::deleteExpression(const Expression *E) const {
const_cast<BasicExpression *>(BE)->deallocateOperands(ArgRecycler);
ExpressionAllocator.Deallocate(E);
}
// Return true if V is really PN, even accounting for predicateinfo copies.
static bool isCopyOfSelf(const Value *V, const PHINode *PN) {
if (V == PN)
return V;
if (auto *II = dyn_cast<IntrinsicInst>(V))
if (II->getIntrinsicID() == Intrinsic::ssa_copy && II->getOperand(0) == PN)
return true;
return false;
}
PHIExpression *NewGVN::createPHIExpression(Instruction *I, bool &HasBackedge,
bool &OriginalOpsConstant) const {
BasicBlock *PHIBlock = getBlockForValue(I);
@ -879,7 +890,7 @@ PHIExpression *NewGVN::createPHIExpression(Instruction *I, bool &HasBackedge,
// Filter out unreachable phi operands.
auto Filtered = make_filter_range(PHIOperands, [&](const Use *U) {
if (*U == PN)
if (isCopyOfSelf(*U, PN))
return false;
if (!ReachableEdges.count({PN->getIncomingBlock(*U), PHIBlock}))
return false;