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PeepholeOpt: Avoid double map lookup #124531

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Merged
merged 3 commits into from
Jan 30, 2025
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PeepholeOpt: Avoid double map lookup #124531

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PeepholeOpt: Avoid double map lookup
arsenm Jan 27, 2025
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arsenm Jan 27, 2025
2def9c1
Update llvm/lib/CodeGen/PeepholeOptimizer.cpp
arsenm Jan 28, 2025
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8 changes: 5 additions & 3 deletions llvm/lib/CodeGen/PeepholeOptimizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1035,8 +1035,11 @@ bool PeepholeOptimizer::findNextSource(RegSubRegPair RegSubReg,
return false;

// Insert the Def -> Use entry for the recently found source.
ValueTrackerResult CurSrcRes = RewriteMap.lookup(CurSrcPair);
if (CurSrcRes.isValid()) {
auto [InsertPt, WasInserted] = RewriteMap.try_emplace(CurSrcPair, Res);

if (!WasInserted) {
const ValueTrackerResult &CurSrcRes = InsertPt->second;

assert(CurSrcRes == Res && "ValueTrackerResult found must match");
// An existent entry with multiple sources is a PHI cycle we must avoid.
// Otherwise it's an entry with a valid next source we already found.
Expand All @@ -1047,7 +1050,6 @@ bool PeepholeOptimizer::findNextSource(RegSubRegPair RegSubReg,
}
break;
}
RewriteMap.insert(std::make_pair(CurSrcPair, Res));

// ValueTrackerResult usually have one source unless it's the result from
// a PHI instruction. Add the found PHI edges to be looked up further.
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