[llvm] bc1e699 - [CodeGen] Avoid repeated hash lookups (NFC) (#123557)

[via llvm-commits]

Author: Kazu Hirata
Date: 2025-01-20T10:13:08-08:00
New Revision: bc1e699d9fb52548c1bc2420f10929473a4c3908

URL: https://github.com/llvm/llvm-project/commit/bc1e699d9fb52548c1bc2420f10929473a4c3908
DIFF: https://github.com/llvm/llvm-project/commit/bc1e699d9fb52548c1bc2420f10929473a4c3908.diff

LOG: [CodeGen] Avoid repeated hash lookups (NFC) (#123557)

Added: 
    

Modified: 
    llvm/lib/CodeGen/MachineCopyPropagation.cpp

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/MachineCopyPropagation.cpp b/llvm/lib/CodeGen/MachineCopyPropagation.cpp
index 0afd73d8ecdccb..d44b064dcb4b2e 100644
--- a/llvm/lib/CodeGen/MachineCopyPropagation.cpp
+++ b/llvm/lib/CodeGen/MachineCopyPropagation.cpp
@@ -127,11 +127,11 @@ class CopyTracker {
   BitVector &getPreservedRegUnits(const MachineOperand &RegMaskOp,
                                   const TargetRegisterInfo &TRI) {
     const uint32_t *RegMask = RegMaskOp.getRegMask();
-    auto Existing = RegMaskToPreservedRegUnits.find(RegMask);
-    if (Existing != RegMaskToPreservedRegUnits.end()) {
-      return Existing->second;
+    auto [It, Inserted] = RegMaskToPreservedRegUnits.try_emplace(RegMask);
+    if (!Inserted) {
+      return It->second;
     } else {
-      BitVector &PreservedRegUnits = RegMaskToPreservedRegUnits[RegMask];
+      BitVector &PreservedRegUnits = It->second;
 
       PreservedRegUnits.resize(TRI.getNumRegUnits());
       for (unsigned SafeReg = 0, E = TRI.getNumRegs(); SafeReg < E; ++SafeReg)