[llvm] [AMDGPU] Avoid repeated hash lookups (NFC) (PR #132511)

[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/132511.diff


1 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/GCNRegPressure.cpp (+4-4) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/GCNRegPressure.cpp b/llvm/lib/Target/AMDGPU/GCNRegPressure.cpp
index a438ad00bc41d..f74d12cfab0c0 100644
--- a/llvm/lib/Target/AMDGPU/GCNRegPressure.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNRegPressure.cpp
@@ -692,8 +692,8 @@ GCNDownwardRPTracker::bumpDownwardPressure(const MachineInstr *MI,
     if (LastUseMask.none())
       continue;
 
-    LaneBitmask LiveMask =
-        LiveRegs.contains(Reg) ? LiveRegs.at(Reg) : LaneBitmask(0);
+    auto It = LiveRegs.find(Reg);
+    LaneBitmask LiveMask = It != LiveRegs.end() ? It->second : LaneBitmask(0);
     LaneBitmask NewMask = LiveMask & ~LastUseMask;
     TempPressure.inc(Reg, LiveMask, NewMask, *MRI);
   }
@@ -703,8 +703,8 @@ GCNDownwardRPTracker::bumpDownwardPressure(const MachineInstr *MI,
     Register Reg = Def.RegUnit;
     if (!Reg.isVirtual())
       continue;
-    LaneBitmask LiveMask =
-        LiveRegs.contains(Reg) ? LiveRegs.at(Reg) : LaneBitmask(0);
+    auto It = LiveRegs.find(Reg);
+    LaneBitmask LiveMask = It != LiveRegs.end() ? It->second : LaneBitmask(0);
     LaneBitmask NewMask = LiveMask | Def.LaneMask;
     TempPressure.inc(Reg, LiveMask, NewMask, *MRI);
   }

``````````

</details>


https://github.com/llvm/llvm-project/pull/132511