[AArch64] Extend CallingConv::X86_64_Win64 to AArch64 as well

Rename the enum value from X86_64_Win64 to plain Win64.

The symbol exposed in the textual IR is changed from 'x86_64_win64cc'
to 'win64cc', but the numeric value is kept, keeping support for
old bitcode.

Differential Revision: https://reviews.llvm.org/D34474

llvm-svn: 308208
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 717eb0e..7204952 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -1670,7 +1670,7 @@
 ///   ::= 'spir_func'
 ///   ::= 'spir_kernel'
 ///   ::= 'x86_64_sysvcc'
-///   ::= 'x86_64_win64cc'
+///   ::= 'win64cc'
 ///   ::= 'webkit_jscc'
 ///   ::= 'anyregcc'
 ///   ::= 'preserve_mostcc'
@@ -1712,7 +1712,7 @@
   case lltok::kw_spir_func:      CC = CallingConv::SPIR_FUNC; break;
   case lltok::kw_intel_ocl_bicc: CC = CallingConv::Intel_OCL_BI; break;
   case lltok::kw_x86_64_sysvcc:  CC = CallingConv::X86_64_SysV; break;
-  case lltok::kw_x86_64_win64cc: CC = CallingConv::X86_64_Win64; break;
+  case lltok::kw_win64cc:        CC = CallingConv::Win64; break;
   case lltok::kw_webkit_jscc:    CC = CallingConv::WebKit_JS; break;
   case lltok::kw_anyregcc:       CC = CallingConv::AnyReg; break;
   case lltok::kw_preserve_mostcc:CC = CallingConv::PreserveMost; break;