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[DAGCombine] Move load checks on store of loads into candidate 

search. NFCI.

Migrate single-use and non-volatility, non-indexed requirements on
stores of immediate store values to candidate collection pass from
later stage.

llvm-svn: 332392
This commit is contained in:
Nirav Dave 2018-05-15 20:31:53 +00:00
parent 28d4ddab86
commit a87de7d846
1 changed files with 13 additions and 15 deletions
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28
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -13258,6 +13258,12 @@ void DAGCombiner::getStoreMergeCandidates(
// Load and store should be the same type.
if (MemVT != LoadVT)
return;
// Loads must only have one use.
if (!Ld->hasNUsesOfValue(1, 0))
return;
// The memory operands must not be volatile.
if (Ld->isVolatile() || Ld->isIndexed())
return;
}
auto CandidateMatch = [&](StoreSDNode *Other, BaseIndexOffset &Ptr,
int64_t &Offset) -> bool {
@ -13275,6 +13281,12 @@ void DAGCombiner::getStoreMergeCandidates(
auto LPtr = BaseIndexOffset::match(OtherLd, DAG);
if (LoadVT != OtherLd->getMemoryVT())
return false;
// Loads must only have one use.
if (!OtherLd->hasNUsesOfValue(1, 0))
return false;
// The memory operands must not be volatile.
if (OtherLd->isVolatile() || OtherLd->isIndexed())
return false;
if (!(LBasePtr.equalBaseIndex(LPtr, DAG)))
return false;
} else
@ -13649,21 +13661,7 @@ bool DAGCombiner::MergeConsecutiveStores(StoreSDNode *St) {
for (unsigned i = 0; i < NumConsecutiveStores; ++i) {
StoreSDNode *St = cast<StoreSDNode>(StoreNodes[i].MemNode);
SDValue Val = peekThroughBitcast(St->getValue());
LoadSDNode *Ld = dyn_cast<LoadSDNode>(Val);
if (!Ld)
break;
// Loads must only have one use.
if (!Ld->hasNUsesOfValue(1, 0))
break;
// The memory operands must not be volatile.
if (Ld->isVolatile() || Ld->isIndexed())
break;
// The stored memory type must be the same.
if (Ld->getMemoryVT() != MemVT)
break;
LoadSDNode *Ld = cast<LoadSDNode>(Val);
BaseIndexOffset LdPtr = BaseIndexOffset::match(Ld, DAG);
// If this is not the first ptr that we check.