[SPIRV] Avoid repeated hash lookups (NFC) (#109517)

Author: kazutakahirata

llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp

@@ -412,9 +412,8 @@ Type *SPIRVEmitIntrinsics::deduceElementTypeHelper(
     return KnownTy;
 
   // maybe a cycle
-  if (Visited.find(I) != Visited.end())
+  if (!Visited.insert(I).second)
     return nullptr;
-  Visited.insert(I);
 
   // fallback value in case when we fail to deduce a type
   Type *Ty = nullptr;
@@ -512,9 +511,8 @@ Type *SPIRVEmitIntrinsics::deduceNestedTypeHelper(
     return KnownTy;
 
   // maybe a cycle
-  if (Visited.find(U) != Visited.end())
+  if (!Visited.insert(U).second)
     return OrigTy;
-  Visited.insert(U);
 
   if (dyn_cast<StructType>(OrigTy)) {
     SmallVector<Type *> Tys;
@@ -1553,9 +1551,8 @@ Type *SPIRVEmitIntrinsics::deduceFunParamElementType(Function *F,
 Type *SPIRVEmitIntrinsics::deduceFunParamElementType(
     Function *F, unsigned OpIdx, std::unordered_set<Function *> &FVisited) {
   // maybe a cycle
-  if (FVisited.find(F) != FVisited.end())
+  if (!FVisited.insert(F).second)
     return nullptr;
-  FVisited.insert(F);
 
   std::unordered_set<Value *> Visited;
   SmallVector<std::pair<Function *, unsigned>> Lookup;