[BOLT] Avoid repeated set lookups (NFC) (#112157)

Author: kazutakahirata

bolt/lib/Passes/Instrumentation.cpp

@@ -109,9 +109,8 @@ static bool hasAArch64ExclusiveMemop(
     BinaryBasicBlock *BB = BBQueue.front().first;
     bool IsLoad = BBQueue.front().second;
     BBQueue.pop();
-    if (Visited.find(BB) != Visited.end())
+    if (!Visited.insert(BB).second)
       continue;
-    Visited.insert(BB);
 
     for (const MCInst &Inst : *BB) {
       // Two loads one after another - skip whole function
@@ -126,8 +125,7 @@ static bool hasAArch64ExclusiveMemop(
       if (BC.MIB->isAArch64ExclusiveLoad(Inst))
         IsLoad = true;
 
-      if (IsLoad && BBToSkip.find(BB) == BBToSkip.end()) {
-        BBToSkip.insert(BB);
+      if (IsLoad && BBToSkip.insert(BB).second) {
         if (opts::Verbosity >= 2) {
           outs() << "BOLT-INSTRUMENTER: skip BB " << BB->getName()
                  << " due to exclusive instruction in function "