[llvm] [AMDGPU] Avoid repeated map lookups (NFC) (PR #112819)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/112819.diff


1 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/SIMachineScheduler.cpp (+5-8) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/SIMachineScheduler.cpp b/llvm/lib/Target/AMDGPU/SIMachineScheduler.cpp
index 7c7e0204b17644..77b4f25021c75d 100644
--- a/llvm/lib/Target/AMDGPU/SIMachineScheduler.cpp
+++ b/llvm/lib/Target/AMDGPU/SIMachineScheduler.cpp
@@ -878,14 +878,11 @@ void SIScheduleBlockCreator::colorAccordingToReservedDependencies() {
     SUColors.first = CurrentTopDownReservedDependencyColoring[SU.NodeNum];
     SUColors.second = CurrentBottomUpReservedDependencyColoring[SU.NodeNum];
 
-    std::map<std::pair<unsigned, unsigned>, unsigned>::iterator Pos =
-      ColorCombinations.find(SUColors);
-    if (Pos != ColorCombinations.end()) {
-      CurrentColoring[SU.NodeNum] = Pos->second;
-    } else {
-      CurrentColoring[SU.NodeNum] = NextNonReservedID;
-      ColorCombinations[SUColors] = NextNonReservedID++;
-    }
+    auto [Pos, Inserted] =
+        ColorCombinations.try_emplace(SUColors, NextNonReservedID);
+    CurrentColoring[SU.NodeNum] = Pos->second;
+    if (Inserted)
+      NextNonReservedID++;
   }
 }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/112819