[X86] Define __APX_F__ when APX is enabled. (#88343)

Relate gcc patch:
https://gcc.gnu.org/pipermail/gcc-patches/2024-April/648789.html

Author: FreddyLeaf

clang/lib/Basic/Targets/X86.cpp

@@ -954,6 +954,9 @@ void X86TargetInfo::getTargetDefines(const LangOptions &Opts,
     Builder.defineMacro("__CCMP__");
   if (HasCF)
     Builder.defineMacro("__CF__");
+  // Condition here is aligned with the feature set of mapxf in Options.td
+  if (HasEGPR && HasPush2Pop2 && HasPPX && HasNDD)
+    Builder.defineMacro("__APX_F__");
 
   // Each case falls through to the previous one here.
   switch (SSELevel) {

clang/test/Preprocessor/x86_target_features.c

@@ -803,7 +803,8 @@
 // RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapx-features=ndd -x c -E -dM -o - %s | FileCheck --check-prefix=NDD %s
 // RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapx-features=ccmp -x c -E -dM -o - %s | FileCheck --check-prefix=CCMP %s
 // RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapx-features=cf -x c -E -dM -o - %s | FileCheck --check-prefix=CF %s
-// RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapxf -x c -E -dM -o - %s | FileCheck --check-prefixes=EGPR,PUSH2POP2,PPX,NDD %s
+// RUN: %clang -target x86_64-unknown-unknown -march=x86-64 -mapxf -x c -E -dM -o - %s | FileCheck --check-prefixes=EGPR,PUSH2POP2,PPX,NDD,APXF %s
+// APXF: #define __APX_F__ 1
 // CCMP: #define __CCMP__ 1
 // CF: #define __CF__ 1
 // EGPR: #define __EGPR__ 1