[clang] [AArch64][SME] Warn when using a streaming builtin from a non-streaming function (PR #74064)

[Sam Tebbs via cfe-commits]

================
@@ -6,20 +6,21 @@
 #include <arm_sme_draft_spec_subject_to_change.h>
 
 __attribute__((target("sme")))
-void test_sme(svbool_t pg, void *ptr) {
+void test_sme(svbool_t pg, void *ptr) __arm_streaming __arm_shared_za {
   svld1_hor_za8(0, 0, pg, ptr);
 }
 
 __attribute__((target("arch=armv8-a+sme")))
-void test_arch_sme(svbool_t pg, void *ptr) {
+void test_arch_sme(svbool_t pg, void *ptr) __arm_streaming __arm_shared_za {
   svld1_hor_vnum_za32(0, 0, pg, ptr, 0);
 }
 
 __attribute__((target("+sme")))
-void test_plus_sme(svbool_t pg, void *ptr) {
+void test_plus_sme(svbool_t pg, void *ptr) __arm_streaming __arm_shared_za {
   svst1_ver_za16(0, 0, pg, ptr);
 }
 
-void undefined(svbool_t pg, void *ptr) {
-  svst1_ver_vnum_za64(0, 0, pg, ptr, 0); // expected-error {{'svst1_ver_vnum_za64' needs target feature sme}}
+__attribute__((target("+sme")))
+void undefined(svbool_t pg, void *ptr) __arm_shared_za {
+  svst1_ver_vnum_za64(0, 0, pg, ptr, 0); // expected-warning {{builtin call has undefined behaviour when called from a non-streaming function}}
----------------
SamTebbs33 wrote:

In a previous review you asked me to do so:

> I think instead you want to compile this test with __attribute__((target("+sme"))) but without the __arm_streaming to ensure you get a diagnostic on the builtin call that the behaviour is undefined when the (parent) function is not a streaming function.

https://github.com/llvm/llvm-project/pull/74064