[clang] [llvm] Clang: convert `__m64` intrinsics to unconditionally use SSE2 instead of MMX. (PR #96540)

[Phoebe Wang via llvm-commits]

================
@@ -21,10 +21,29 @@ typedef int __v2si __attribute__((__vector_size__(8)));
 typedef short __v4hi __attribute__((__vector_size__(8)));
 typedef char __v8qi __attribute__((__vector_size__(8)));
 
+/* Unsigned types */
+typedef unsigned long long __v1du __attribute__ ((__vector_size__ (8)));
+typedef unsigned int __v2su __attribute__ ((__vector_size__ (8)));
+typedef unsigned short __v4hu __attribute__((__vector_size__(8)));
+typedef unsigned char __v8qu __attribute__((__vector_size__(8)));
+
+/* We need an explicitly signed variant for char. Note that this shouldn't
+ * appear in the interface though. */
+typedef signed char __v8qs __attribute__((__vector_size__(8)));
+
+/* SSE/SSE2 types */
+typedef long long __m128i __attribute__((__vector_size__(16), __aligned__(16)));
+typedef long long __v2di __attribute__ ((__vector_size__ (16)));
+typedef int __v4si __attribute__((__vector_size__(16)));
+typedef short __v8hi __attribute__((__vector_size__(16)));
+typedef char __v16qi __attribute__((__vector_size__(16)));
+
 /* Define the default attributes for the functions in this file. */
-#define __DEFAULT_FN_ATTRS                                                     \
-  __attribute__((__always_inline__, __nodebug__, __target__("mmx,no-evex512"), \
-                 __min_vector_width__(64)))
+#define __DEFAULT_FN_ATTRS_SSE2 __attribute__((__always_inline__, __nodebug__, __target__("sse2,no-evex512"), __min_vector_width__(64)))
----------------
phoebewang wrote:

They are used to identify the maximum registers a function will use. The backend doesn't distinguish the difference between scalar and 128-bit for now. But we should make it comply the rule here.

https://github.com/llvm/llvm-project/pull/96540