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

[Fangrui Song via cfe-commits]

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@@ -197,6 +197,7 @@ CODEGENOPT(HIPCorrectlyRoundedDivSqrt, 1, 1) ///< -fno-hip-fp32-correctly-rounde
 CODEGENOPT(HIPSaveKernelArgName, 1, 0) ///< Set when -fhip-kernel-arg-name is enabled.
 CODEGENOPT(UniqueInternalLinkageNames, 1, 0) ///< Internal Linkage symbols get unique names.
 CODEGENOPT(SplitMachineFunctions, 1, 0) ///< Split machine functions using profile information.
+CODEGENOPT(UseFullRegisterNames, 1, 0) ///< Print full register names in assembly -mregnames
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MaskRay wrote:

`PPCUseFullRegisterNames` or `PPCFullRegisterNames`

This is rs6000-specific in gcc.

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