[llvm] [Hexagon] Avoid repeated hash lookups (NFC) (PR #125459)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-hexagon

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/125459.diff


1 Files Affected:

- (modified) llvm/lib/Target/Hexagon/HexagonLoopIdiomRecognition.cpp (+6-8) 


``````````diff
diff --git a/llvm/lib/Target/Hexagon/HexagonLoopIdiomRecognition.cpp b/llvm/lib/Target/Hexagon/HexagonLoopIdiomRecognition.cpp
index d2ae2ef7bd7ff3..41803e66a0f8e0 100644
--- a/llvm/lib/Target/Hexagon/HexagonLoopIdiomRecognition.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonLoopIdiomRecognition.cpp
@@ -1388,14 +1388,12 @@ bool PolynomialMultiplyRecognize::convertShiftsToLeft(BasicBlock *LoopB,
 
   CastMapType CastMap;
 
-  auto upcast = [] (CastMapType &CM, IRBuilder<> &IRB, Value *V,
-        IntegerType *Ty) -> Value* {
-    auto H = CM.find(std::make_pair(V, Ty));
-    if (H != CM.end())
-      return H->second;
-    Value *CV = IRB.CreateIntCast(V, Ty, false);
-    CM.insert(std::make_pair(std::make_pair(V, Ty), CV));
-    return CV;
+  auto upcast = [](CastMapType &CM, IRBuilder<> &IRB, Value *V,
+                   IntegerType *Ty) -> Value * {
+    auto [H, Inserted] = CM.try_emplace(std::make_pair(V, Ty));
+    if (Inserted)
+      H->second = IRB.CreateIntCast(V, Ty, false);
+    return H->second;
   };
 
   for (auto I = LoopB->begin(), E = LoopB->end(); I != E; ++I) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/125459