[llvm] [Hexagon] Avoid repeated hash lookups (NFC) (PR #107760)

[Nikita Popov via llvm-commits]

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@@ -297,10 +297,8 @@ LaneBitmask HexagonExpandCondsets::getLaneMask(Register Reg, unsigned Sub) {
 void HexagonExpandCondsets::addRefToMap(RegisterRef RR, ReferenceMap &Map,
       unsigned Exec) {
   unsigned Mask = getMaskForSub(RR.Sub) | Exec;
-  ReferenceMap::iterator F = Map.find(RR.Reg);
-  if (F == Map.end())
-    Map.insert(std::make_pair(RR.Reg, Mask));
-  else
+  auto [F, Inserted] = Map.try_emplace(RR.Reg, Mask);
+  if (!Inserted)
     F->second |= Mask;
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nikic wrote:

I think this function would be more elegantly written as just `Map[RR.Reg] |= Mask`, making use of 0 default initialization.

https://github.com/llvm/llvm-project/pull/107760