[llvm] [NewPM][CodeGen] Port `regallocfast` to new pass manager (PR #94426)

[Arthur Eubanks via llvm-commits]

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@@ -1161,6 +1162,38 @@ Expected<SmallVector<std::string, 0>> parseInternalizeGVs(StringRef Params) {
   return Expected<SmallVector<std::string, 0>>(std::move(PreservedGVs));
 }
 
+Expected<RegAllocFastPassOptions>
+parseRegAllocFastPassOptions(PassBuilder &PB, StringRef Params) {
+  RegAllocFastPassOptions Opts;
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aeubanks wrote:

add a test for parsing/pipeline printing roundtrip

https://github.com/llvm/llvm-project/pull/94426