[clang] [llvm] [ARM] __ARM_ARCH macro definition fix (PR #81493)

[via llvm-commits]

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@@ -367,8 +367,21 @@ void AArch64TargetInfo::getTargetDefines(const LangOptions &Opts,
 
   // ACLE predefines. Many can only have one possible value on v8 AArch64.
   Builder.defineMacro("__ARM_ACLE", "200");
-  Builder.defineMacro("__ARM_ARCH",
-                      std::to_string(ArchInfo->Version.getMajor()));
+
+  // ACLE 5.4.1 ARM/Thumb instruction set architecture
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ostannard wrote:

Nit: the ACLE doesn't use section numbers any more, and and the ARM/Thumb ISAs only apply to AArch32. I think this line of the comment can just be removed.

https://github.com/llvm/llvm-project/pull/81493