[llvm] [Scalar] Avoid repeated hash lookups (NFC) (PR #126189)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/126189.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Scalar/GVNHoist.cpp (+4-5) 


``````````diff
diff --git a/llvm/lib/Transforms/Scalar/GVNHoist.cpp b/llvm/lib/Transforms/Scalar/GVNHoist.cpp
index c6f015112e59df1..1c2e1531e47d882 100644
--- a/llvm/lib/Transforms/Scalar/GVNHoist.cpp
+++ b/llvm/lib/Transforms/Scalar/GVNHoist.cpp
@@ -564,21 +564,20 @@ unsigned int GVNHoist::rank(const Value *V) const {
 }
 
 bool GVNHoist::hasEH(const BasicBlock *BB) {
-  auto It = BBSideEffects.find(BB);
-  if (It != BBSideEffects.end())
+  auto [It, Inserted] = BBSideEffects.try_emplace(BB);
+  if (!Inserted)
     return It->second;
 
   if (BB->isEHPad() || BB->hasAddressTaken()) {
-    BBSideEffects[BB] = true;
+    It->second = true;
     return true;
   }
 
   if (BB->getTerminator()->mayThrow()) {
-    BBSideEffects[BB] = true;
+    It->second = true;
     return true;
   }
 
-  BBSideEffects[BB] = false;
   return false;
 }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/126189