[clang] [llvm] [X86] Support EGPR for inline assembly. (PR #92338)

[Shengchen Kan via cfe-commits]

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@@ -450,6 +450,8 @@ bool X86TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
       HasFullBFloat16 = true;
     } else if (Feature == "+egpr") {
       HasEGPR = true;
+    } else if (Feature == "+inline-asm-use-gpr32") {
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KanRobert wrote:

> `mcmodel` maybe not a good reference here since it's target independent.

```
  if (Opts.MicrosoftExt && getTriple().getArch() == llvm::Triple::x86) {
    switch (SSELevel) {
    case AVX512F:
    case AVX2:
    case AVX:
    case SSE42:
    case SSE41:
    case SSSE3:
    case SSE3:
    case SSE2:
      Builder.defineMacro("_M_IX86_FP", Twine(2));
      break;
    case SSE1:
      Builder.defineMacro("_M_IX86_FP", Twine(1));
      break;
    default:
      Builder.defineMacro("_M_IX86_FP", Twine(0));
      break;
    }
  }
```


https://github.com/llvm/llvm-project/pull/92338