From 1bf4fe9e5128ceec3a7249052b5f005e094501aa Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu@google.com>
Date: Thu, 20 Mar 2025 09:41:32 -0700
Subject: [PATCH] [Scalar] Avoid repeated hash lookups (NFC)
---
.../Scalar/RewriteStatepointsForGC.cpp | 20 ++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
index 364fe5a9fad11..ef425e0318ea9 100644
--- a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
+++ b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
@@ -1182,11 +1182,12 @@ static Value *findBasePointer(Value *I, DefiningValueMapTy &Cache,
for (unsigned i = 0; i < NumPHIValues; i++) {
Value *InVal = PN->getIncomingValue(i);
BasicBlock *InBB = PN->getIncomingBlock(i);
- if (!BlockToValue.count(InBB))
- BlockToValue[InBB] = getBaseForInput(InVal, InBB->getTerminator());
+ auto [It, Inserted] = BlockToValue.try_emplace(InBB);
+ if (Inserted)
+ It->second = getBaseForInput(InVal, InBB->getTerminator());
else {
#ifndef NDEBUG
- Value *OldBase = BlockToValue[InBB];
+ Value *OldBase = It->second;
Value *Base = getBaseForInput(InVal, nullptr);
// We can't use `stripPointerCasts` instead of this function because
@@ -1206,7 +1207,7 @@ static Value *findBasePointer(Value *I, DefiningValueMapTy &Cache,
"findBaseOrBDV should be pure!");
#endif
}
- Value *Base = BlockToValue[InBB];
+ Value *Base = It->second;
BasePHI->setIncomingValue(i, Base);
}
} else if (SelectInst *BaseSI =
@@ -1545,9 +1546,10 @@ static void CreateGCRelocates(ArrayRef<Value *> LiveVariables,
Value *LiveIdx = Builder.getInt32(i);
Type *Ty = LiveVariables[i]->getType();
- if (!TypeToDeclMap.count(Ty))
- TypeToDeclMap[Ty] = getGCRelocateDecl(Ty);
- Function *GCRelocateDecl = TypeToDeclMap[Ty];
+ auto [It, Inserted] = TypeToDeclMap.try_emplace(Ty);
+ if (Inserted)
+ It->second = getGCRelocateDecl(Ty);
+ Function *GCRelocateDecl = It->second;
// only specify a debug name if we can give a useful one
CallInst *Reloc = Builder.CreateCall(
@@ -2378,9 +2380,9 @@ findRematerializationCandidates(PointerToBaseTy PointerToBase,
// Handle the scenario where the RootOfChain is not equal to the
// Base Value, but they are essentially the same phi values.
- if (RootOfChain != PointerToBase[Derived]) {
+ if (Value *BaseVal = PointerToBase[Derived]; RootOfChain != BaseVal) {
PHINode *OrigRootPhi = dyn_cast<PHINode>(RootOfChain);
- PHINode *AlternateRootPhi = dyn_cast<PHINode>(PointerToBase[Derived]);
+ PHINode *AlternateRootPhi = dyn_cast<PHINode>(BaseVal);
if (!OrigRootPhi || !AlternateRootPhi)
continue;
// PHI nodes that have the same incoming values, and belonging to the same