[Transforms] Use StringRef::operator== instead of StringRef::equals (NFC) (#91072)

I'm planning to remove StringRef::equals in favor of
StringRef::operator==.

- StringRef::operator==/!= outnumber StringRef::equals by a factor of
  31 under llvm/ in terms of their usage.

- The elimination of StringRef::equals brings StringRef closer to
  std::string_view, which has operator== but not equals.

- S == "foo" is more readable than S.equals("foo"), especially for
  !Long.Expression.equals("str") vs Long.Expression != "str".

Author: kazutakahirata

llvm/lib/Transforms/Coroutines/CoroSplit.cpp

@@ -1846,11 +1846,10 @@ static void splitAsyncCoroutine(Function &F, coro::Shape &Shape,
     auto ProjectionFunctionName =
         Suspend->getAsyncContextProjectionFunction()->getName();
     bool UseSwiftMangling = false;
-    if (ProjectionFunctionName.equals("__swift_async_resume_project_context")) {
+    if (ProjectionFunctionName == "__swift_async_resume_project_context") {
       ResumeNameSuffix = "TQ";
       UseSwiftMangling = true;
-    } else if (ProjectionFunctionName.equals(
-                   "__swift_async_resume_get_context")) {
+    } else if (ProjectionFunctionName == "__swift_async_resume_get_context") {
       ResumeNameSuffix = "TY";
       UseSwiftMangling = true;
     }

llvm/lib/Transforms/IPO/BlockExtractor.cpp

@@ -142,9 +142,8 @@ bool BlockExtractor::runOnModule(Module &M) {
       report_fatal_error("Invalid function name specified in the input file",
                          /*GenCrashDiag=*/false);
     for (const auto &BBInfo : BInfo.second) {
-      auto Res = llvm::find_if(*F, [&](const BasicBlock &BB) {
-        return BB.getName().equals(BBInfo);
-      });
+      auto Res = llvm::find_if(
+          *F, [&](const BasicBlock &BB) { return BB.getName() == BBInfo; });
       if (Res == F->end())
         report_fatal_error("Invalid block name specified in the input file",
                            /*GenCrashDiag=*/false);

llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp

@@ -2125,7 +2125,7 @@ static bool annotateAllFunctions(
       HotFunctions.push_back(&F);
     if (PGOViewCounts != PGOVCT_None &&
         (ViewBlockFreqFuncName.empty() ||
-         F.getName().equals(ViewBlockFreqFuncName))) {
+         F.getName() == ViewBlockFreqFuncName)) {
       LoopInfo LI{DominatorTree(F)};
       std::unique_ptr<BranchProbabilityInfo> NewBPI =
           std::make_unique<BranchProbabilityInfo>(F, LI);
@@ -2140,7 +2140,7 @@ static bool annotateAllFunctions(
     }
     if (PGOViewRawCounts != PGOVCT_None &&
         (ViewBlockFreqFuncName.empty() ||
-         F.getName().equals(ViewBlockFreqFuncName))) {
+         F.getName() == ViewBlockFreqFuncName)) {
       if (PGOViewRawCounts == PGOVCT_Graph)
         if (ViewBlockFreqFuncName.empty())
           WriteGraph(&Func, Twine("PGORawCounts_") + Func.getFunc().getName());

llvm/lib/Transforms/Scalar/ADCE.cpp

@@ -350,7 +350,7 @@ bool AggressiveDeadCodeElimination::isInstrumentsConstant(Instruction &I) {
   // TODO -- move this test into llvm::isInstructionTriviallyDead
   if (CallInst *CI = dyn_cast<CallInst>(&I))
     if (Function *Callee = CI->getCalledFunction())
-      if (Callee->getName().equals(getInstrProfValueProfFuncName()))
+      if (Callee->getName() == getInstrProfValueProfFuncName())
         if (isa<Constant>(CI->getArgOperand(0)))
           return true;
   return false;

llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp

@@ -591,7 +591,7 @@ static Instruction *findLocationForEntrySafepoint(Function &F,
 const char GCSafepointPollName[] = "gc.safepoint_poll";
 
 static bool isGCSafepointPoll(Function &F) {
-  return F.getName().equals(GCSafepointPollName);
+  return F.getName() == GCSafepointPollName;
 }
 
 /// Returns true if this function should be rewritten to include safepoint

llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp

@@ -1685,10 +1685,10 @@ makeStatepointExplicitImpl(CallBase *Call, /* to replace */
 
   // Pass through the requested lowering if any.  The default is live-through.
   StringRef DeoptLowering = getDeoptLowering(Call);
-  if (DeoptLowering.equals("live-in"))
+  if (DeoptLowering == "live-in")
     Flags |= uint32_t(StatepointFlags::DeoptLiveIn);
   else {
-    assert(DeoptLowering.equals("live-through") && "Unsupported value!");
+    assert(DeoptLowering == "live-through" && "Unsupported value!");
   }
 
   FunctionCallee CallTarget(Call->getFunctionType(), Call->getCalledOperand());

llvm/lib/Transforms/Utils/LoopUnroll.cpp

@@ -1077,7 +1077,7 @@ MDNode *llvm::GetUnrollMetadata(MDNode *LoopID, StringRef Name) {
     if (!S)
       continue;
 
-    if (Name.equals(S->getString()))
+    if (Name == S->getString())
       return MD;
   }
   return nullptr;

llvm/lib/Transforms/Utils/LoopUtils.cpp

@@ -222,7 +222,7 @@ void llvm::addStringMetadataToLoop(Loop *TheLoop, const char *StringMD,
       // If it is of form key = value, try to parse it.
       if (Node->getNumOperands() == 2) {
         MDString *S = dyn_cast<MDString>(Node->getOperand(0));
-        if (S && S->getString().equals(StringMD)) {
+        if (S && S->getString() == StringMD) {
           ConstantInt *IntMD =
               mdconst::extract_or_null<ConstantInt>(Node->getOperand(1));
           if (IntMD && IntMD->getSExtValue() == V)

llvm/lib/Transforms/Utils/SymbolRewriter.cpp

@@ -308,11 +308,11 @@ bool RewriteMapParser::parseEntry(yaml::Stream &YS, yaml::KeyValueNode &Entry,
   }
 
   RewriteType = Key->getValue(KeyStorage);
-  if (RewriteType.equals("function"))
+  if (RewriteType == "function")
     return parseRewriteFunctionDescriptor(YS, Key, Value, DL);
-  else if (RewriteType.equals("global variable"))
+  else if (RewriteType == "global variable")
     return parseRewriteGlobalVariableDescriptor(YS, Key, Value, DL);
-  else if (RewriteType.equals("global alias"))
+  else if (RewriteType == "global alias")
     return parseRewriteGlobalAliasDescriptor(YS, Key, Value, DL);
 
   YS.printError(Entry.getKey(), "unknown rewrite type");
@@ -348,19 +348,19 @@ parseRewriteFunctionDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
     }
 
     KeyValue = Key->getValue(KeyStorage);
-    if (KeyValue.equals("source")) {
+    if (KeyValue == "source") {
       std::string Error;
 
       Source = std::string(Value->getValue(ValueStorage));
       if (!Regex(Source).isValid(Error)) {
         YS.printError(Field.getKey(), "invalid regex: " + Error);
         return false;
       }
-    } else if (KeyValue.equals("target")) {
+    } else if (KeyValue == "target") {
       Target = std::string(Value->getValue(ValueStorage));
-    } else if (KeyValue.equals("transform")) {
+    } else if (KeyValue == "transform") {
       Transform = std::string(Value->getValue(ValueStorage));
-    } else if (KeyValue.equals("naked")) {
+    } else if (KeyValue == "naked") {
       std::string Undecorated;
 
       Undecorated = std::string(Value->getValue(ValueStorage));
@@ -417,17 +417,17 @@ parseRewriteGlobalVariableDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
     }
 
     KeyValue = Key->getValue(KeyStorage);
-    if (KeyValue.equals("source")) {
+    if (KeyValue == "source") {
       std::string Error;
 
       Source = std::string(Value->getValue(ValueStorage));
       if (!Regex(Source).isValid(Error)) {
         YS.printError(Field.getKey(), "invalid regex: " + Error);
         return false;
       }
-    } else if (KeyValue.equals("target")) {
+    } else if (KeyValue == "target") {
       Target = std::string(Value->getValue(ValueStorage));
-    } else if (KeyValue.equals("transform")) {
+    } else if (KeyValue == "transform") {
       Transform = std::string(Value->getValue(ValueStorage));
     } else {
       YS.printError(Field.getKey(), "unknown Key for Global Variable");
@@ -480,17 +480,17 @@ parseRewriteGlobalAliasDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
     }
 
     KeyValue = Key->getValue(KeyStorage);
-    if (KeyValue.equals("source")) {
+    if (KeyValue == "source") {
       std::string Error;
 
       Source = std::string(Value->getValue(ValueStorage));
       if (!Regex(Source).isValid(Error)) {
         YS.printError(Field.getKey(), "invalid regex: " + Error);
         return false;
       }
-    } else if (KeyValue.equals("target")) {
+    } else if (KeyValue == "target") {
       Target = std::string(Value->getValue(ValueStorage));
-    } else if (KeyValue.equals("transform")) {
+    } else if (KeyValue == "transform") {
       Transform = std::string(Value->getValue(ValueStorage));
     } else {
       YS.printError(Field.getKey(), "unknown key for Global Alias");

llvm/unittests/Transforms/Utils/LocalTest.cpp

@@ -1196,7 +1196,7 @@ TEST(Local, SimplifyCFGWithNullAC) {
   // Obtain BasicBlock of interest to this test, %test.bb.
   BasicBlock *TestBB = nullptr;
   for (BasicBlock &BB : F) {
-    if (BB.getName().equals("test.bb")) {
+    if (BB.getName() == "test.bb") {
       TestBB = &BB;
       break;
     }