[llvm] [GVNSink] Avoid repeated hash lookups (NFC) (PR #113023)

[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/113023.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Scalar/GVNSink.cpp (+3-3) 


``````````diff
diff --git a/llvm/lib/Transforms/Scalar/GVNSink.cpp b/llvm/lib/Transforms/Scalar/GVNSink.cpp
index 3dfa2dd9df27f5..42b44725240f29 100644
--- a/llvm/lib/Transforms/Scalar/GVNSink.cpp
+++ b/llvm/lib/Transforms/Scalar/GVNSink.cpp
@@ -535,12 +535,12 @@ class ValueTable {
     uint32_t e = ExpressionNumbering[exp];
     if (!e) {
       hash_code H = exp->getHashValue([=](Value *V) { return lookupOrAdd(V); });
-      auto I = HashNumbering.find(H);
-      if (I != HashNumbering.end()) {
+      auto [I, Inserted] = HashNumbering.try_emplace(H);
+      if (!Inserted) {
         e = I->second;
       } else {
         e = nextValueNumber++;
-        HashNumbering[H] = e;
+        I->second = e;
         ExpressionNumbering[exp] = e;
       }
     }

``````````

</details>


https://github.com/llvm/llvm-project/pull/113023