__is_target_arch: Check the arch and subarch instead of the arch name

This ensures that when compiling for "arm64" __is_target_arch will succeed for
both "arm64" and "aarch64".

Thanks to Bob Wilson who pointed this out!

llvm-svn: 320853

clang/lib/Lex/PPMacroExpansion.cpp

@@ -1615,9 +1615,9 @@ static bool isTargetArch(const TargetInfo &TI, const IdentifierInfo *II) {
   }
   // Check the parsed arch when it has no sub arch to allow Clang to
   // match thumb to thumbv7 but to prohibit matching thumbv6 to thumbv7.
-  return (Arch.getSubArch() == llvm::Triple::NoSubArch &&
-          Arch.getArch() == TT.getArch()) ||
-         Arch.getArchName() == TT.getArchName();
+  return (Arch.getSubArch() == llvm::Triple::NoSubArch ||
+          Arch.getSubArch() == TT.getSubArch()) &&
+         Arch.getArch() == TT.getArch();
 }
 
 /// Implements the __is_target_vendor builtin macro.

clang/test/Preprocessor/is_target_arm64.c

@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -fsyntax-only -triple arm64-apple-ios11 -verify %s
+// expected-no-diagnostics
+
+#if !__is_target_arch(arm64) || !__is_target_arch(aarch64)
+  #error "mismatching arch"
+#endif
+
+#if __is_target_arch(aarch64_be)
+  #error "mismatching arch"
+#endif