[llvm] [clang] [PowerPC] Add an alias for -mregnames so that full register names used in assembly. (PR #70255)

[Fangrui Song via cfe-commits]

================
@@ -1780,6 +1780,9 @@ bool CompilerInvocation::ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args,
       Opts.setDebugInfo(llvm::codegenoptions::LimitedDebugInfo);
   }
 
+  if (const Arg *A = Args.getLastArg(OPT_mregnames))
+    Opts.PPCUseFullRegisterNames = true;
----------------
MaskRay wrote:

With `CodeGenOpts<"PPCUseFullRegisterNames">` this is unneeded

https://github.com/llvm/llvm-project/pull/70255