[llvm] [CodeGen][NPM] Support generic regalloc-npm option (PR #172485)

[Arthur Eubanks via llvm-commits]

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@@ -1135,32 +1155,76 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addTargetRegisterAllocator(
     addMachineFunctionPass(RegAllocFastPass(), PMW);
 }
 
+template <typename Derived, typename TargetMachineT>
+template <typename RegAllocPassBuilderT>
+void CodeGenPassBuilder<Derived, TargetMachineT>::addRegAllocPassOrOpt(
+    PassManagerWrapper &PMW, RegAllocPassBuilderT PassBuilder) const {
+  if (auto Err = addRegAllocPassFromOpt(PMW)) {
+    report_fatal_error(std::move(Err));
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aeubanks wrote:

if any part of the pipeline construction fails, is there any reason to bubble up the error rather than immediately report an error?

https://github.com/llvm/llvm-project/pull/172485