[llvm] [LiveDebugValues] Avoid repeated hash lookups (NFC) (PR #110379)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-debuginfo

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/110379.diff


1 Files Affected:

- (modified) llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp (+4-6) 


``````````diff
diff --git a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
index a73a3aa59403b3..a9d28a39c4418b 100644
--- a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
+++ b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
@@ -3958,12 +3958,10 @@ class LDVSSAUpdater {
   /// For a given MBB, create a wrapper block for it. Stores it in the
   /// LDVSSAUpdater block map.
   LDVSSABlock *getSSALDVBlock(MachineBasicBlock *BB) {
-    auto it = BlockMap.find(BB);
-    if (it == BlockMap.end()) {
-      BlockMap[BB] = new LDVSSABlock(*BB, *this);
-      it = BlockMap.find(BB);
-    }
-    return it->second;
+    auto [It, Inserted] = BlockMap.try_emplace(BB);
+    if (Inserted)
+      It->second = new LDVSSABlock(*BB, *this);
+    return It->second;
   }
 
   /// Find the live-in value number for the given block. Looks up the value at

``````````

</details>


https://github.com/llvm/llvm-project/pull/110379