[llvm] [PassInstrumentation] Make getPassNameForClassName return optional (PR #150029)

[Nikita Popov via llvm-commits]

================
@@ -164,7 +164,7 @@ int llvm::compileModuleWithNewPM(
     raw_string_ostream OS(PipelineStr);
     MPM.printPipeline(OS, [&PIC](StringRef ClassName) {
       auto PassName = PIC.getPassNameForClassName(ClassName);
-      return PassName.empty() ? ClassName : PassName;
+      return PassName ? ClassName : *PassName;
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nikic wrote:

```suggestion
      return !PassName ? ClassName : *PassName;
```

https://github.com/llvm/llvm-project/pull/150029