[win][arm64ec] XFAIL x64 intrinsic tests on Arm64EC (#153474)

Clang defines the x64 preprocessor macro (`__x86_64__`) when building
Arm64EC, however the tests for x64 built-ins and intrinsics are
currently failing since the relevant functions don't exist, resulting in
errors like:

```
Line 165: invalid conversion between vector type '__v2di' (vector of 2 'long long' values) and integer type 'int' of different size
```

(Clang doesn't know the intrinsics being called, and so treats it like
an undefined function, which makes it assume the return type is `int`)

For now, expect these tests to fail until someone decides to implement
these intrinsics.

Author: dpaoliello

clang/test/Headers/mm3dnow.c

@@ -2,6 +2,9 @@
 // RUN: %clang_cc1 -fsyntax-only -D_CLANG_DISABLE_CRT_DEPRECATION_WARNINGS -ffreestanding %s -verify
 // RUN: %clang_cc1 -fsyntax-only -ffreestanding -x c++ %s -verify
 
+// XFAIL: target=arm64ec-pc-windows-msvc
+// These intrinsics are not yet implemented for Arm64EC.
+
 #if defined(i386) || defined(__x86_64__)
 #ifndef _CLANG_DISABLE_CRT_DEPRECATION_WARNINGS
 // [email protected]:*{{The <mm3dnow.h> header is deprecated}}

clang/test/Headers/pmmintrin.c

@@ -2,6 +2,9 @@
 // RUN: %clang_cc1 -fsyntax-only -ffreestanding -x c++ %s -verify
 // expected-no-diagnostics
 
+// XFAIL: target=arm64ec-pc-windows-msvc
+// These intrinsics are not yet implemented for Arm64EC.
+
 #if defined(i386) || defined(__x86_64__)
 #include <pmmintrin.h>
 

clang/test/Headers/x86-intrinsics-headers.c

@@ -2,6 +2,9 @@
 // RUN: %clang_cc1 -fsyntax-only -ffreestanding -flax-vector-conversions=none %s
 // RUN: %clang_cc1 -fsyntax-only -ffreestanding -x c++ %s
 
+// XFAIL: target=arm64ec-pc-windows-msvc
+// These intrinsics are not yet implemented for Arm64EC.
+
 #if defined(i386) || defined(__x86_64__)
 
 #ifdef __SSE4_2__

clang/test/Headers/x86intrin.c

@@ -3,6 +3,9 @@
 // RUN: %clang_cc1 -fsyntax-only -ffreestanding -x c++ %s -verify
 // expected-no-diagnostics
 
+// XFAIL: target=arm64ec-pc-windows-msvc
+// These intrinsics are not yet implemented for Arm64EC.
+
 #if defined(i386) || defined(__x86_64__)
 
 // Include the metaheader that includes all x86 intrinsic headers.

clang/test/Headers/x86intrin.cpp

@@ -1,6 +1,9 @@
 // RUN: %clang_cc1 -fsyntax-only -ffreestanding %s -verify
 // expected-no-diagnostics
 
+// XFAIL: target=arm64ec-pc-windows-msvc
+// These intrinsics are not yet implemented for Arm64EC.
+
 #if defined(i386) || defined(__x86_64__)
 
 // Include the metaheader that includes all x86 intrinsic headers.