[SLP] Avoid repeated hash lookups (NFC) (#115428)

kazutakahirata · web-flow · commit bc7e5c2016e2 · 2024-11-08T07:35:06.000-08:00
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -2241,10 +2241,9 @@ class BoUpSLP {
           HashMap[NumFreeOpsHash.Hash] = std::make_pair(1, Lane);
         } else if (NumFreeOpsHash.NumOfAPOs == Min &&
                    NumFreeOpsHash.NumOpsWithSameOpcodeParent == SameOpNumber) {
-          auto *It = HashMap.find(NumFreeOpsHash.Hash);
-          if (It == HashMap.end())
-            HashMap[NumFreeOpsHash.Hash] = std::make_pair(1, Lane);
-          else
+          auto [It, Inserted] =
+              HashMap.try_emplace(NumFreeOpsHash.Hash, 1, Lane);
+          if (!Inserted)
             ++It->second.first;
         }
       }

Original file line number	Diff line number	Diff line change
`@@ -2241,10 +2241,9 @@ class BoUpSLP {`
`2241`	`2241`	`HashMap[NumFreeOpsHash.Hash] = std::make_pair(1, Lane);`
`2242`	`2242`	`} else if (NumFreeOpsHash.NumOfAPOs == Min &&`
`2243`	`2243`	`NumFreeOpsHash.NumOpsWithSameOpcodeParent == SameOpNumber) {`
`2244`		`- auto *It = HashMap.find(NumFreeOpsHash.Hash);`
`2245`		`- if (It == HashMap.end())`
`2246`		`- HashMap[NumFreeOpsHash.Hash] = std::make_pair(1, Lane);`
`2247`		`- else`
	`2244`	`+ auto [It, Inserted] =`
	`2245`	`+ HashMap.try_emplace(NumFreeOpsHash.Hash, 1, Lane);`
	`2246`	`+ if (!Inserted)`
`2248`	`2247`	`++It->second.first;`
`2249`	`2248`	`}`
`2250`	`2249`	`}`