[llvm] [Transforms] Avoid repeated hash lookups (NFC) (PR #131497)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/131497

None

>From 9e44a5f78de46e378948da426f755b97cc551a6b Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sat, 15 Mar 2025 09:21:08 -0700
Subject: [PATCH] [Transforms] Avoid repeated hash lookups (NFC)

---
 llvm/lib/Transforms/IPO/FunctionAttrs.cpp | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index 1fca1b54065d4..f70686bc57ee4 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -319,8 +319,8 @@ static FunctionSummary *calculatePrevailingSummary(
     function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
         IsPrevailing) {
 
-  if (auto It = CachedPrevailingSummary.find(VI);
-      It != CachedPrevailingSummary.end())
+  auto [It, Inserted] = CachedPrevailingSummary.try_emplace(VI);
+  if (!Inserted)
     return It->second;
 
   /// At this point, prevailing symbols have been resolved. The following leads
@@ -363,7 +363,6 @@ static FunctionSummary *calculatePrevailingSummary(
   ///      future this can be revisited.
   ///   5. Otherwise, go conservative.
 
-  CachedPrevailingSummary[VI] = nullptr;
   FunctionSummary *Local = nullptr;
   FunctionSummary *Prevailing = nullptr;
 
@@ -764,12 +763,12 @@ ArgumentUsesSummary collectArgumentUsesPerBlock(Argument &A, Function &F) {
   auto UpdateUseInfo = [&Result](Instruction *I, ArgumentAccessInfo Info) {
     auto *BB = I->getParent();
     auto &BBInfo = Result.UsesPerBlock[BB];
-    bool AlreadyVisitedInst = BBInfo.Insts.contains(I);
-    auto &IInfo = BBInfo.Insts[I];
+    auto [It, Inserted] = BBInfo.Insts.try_emplace(I);
+    auto &IInfo = It->second;
 
     // Instructions that have more than one use of the argument are considered
     // as clobbers.
-    if (AlreadyVisitedInst) {
+    if (!Inserted) {
       IInfo = {ArgumentAccessInfo::AccessType::Unknown, {}};
       BBInfo.HasUnknownAccess = true;
       return false;