[llvm] 312c1cf - [CodeGen] Avoid repeated hash lookups (NFC) (#110203)

[via llvm-commits]

Author: Kazu Hirata
Date: 2024-09-28T10:04:44-07:00
New Revision: 312c1cfbd165f56c0d092933b7a829f054afe323

URL: https://github.com/llvm/llvm-project/commit/312c1cfbd165f56c0d092933b7a829f054afe323
DIFF: https://github.com/llvm/llvm-project/commit/312c1cfbd165f56c0d092933b7a829f054afe323.diff

LOG: [CodeGen] Avoid repeated hash lookups (NFC) (#110203)

Added: 
    

Modified: 
    llvm/lib/CodeGen/MachinePipeliner.cpp

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/MachinePipeliner.cpp b/llvm/lib/CodeGen/MachinePipeliner.cpp
index cd8333931bb5f9..5475743905032c 100644
--- a/llvm/lib/CodeGen/MachinePipeliner.cpp
+++ b/llvm/lib/CodeGen/MachinePipeliner.cpp
@@ -1415,14 +1415,12 @@ class HighRegisterPressureDetector {
         auto Reg = Use.RegUnit;
         if (!TargetRegs.contains(Reg))
           continue;
-        auto Ite = LastUseMI.find(Reg);
-        if (Ite == LastUseMI.end()) {
-          LastUseMI[Reg] = MI;
-        } else {
+        auto [Ite, Inserted] = LastUseMI.try_emplace(Reg, MI);
+        if (!Inserted) {
           MachineInstr *Orig = Ite->second;
           MachineInstr *New = MI;
           if (InstrScore(Orig) < InstrScore(New))
-            LastUseMI[Reg] = New;
+            Ite->second = New;
         }
       }
     }