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

[Sam Tebbs via cfe-commits]

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@@ -20,3 +21,23 @@ int16x8_t incompat_neon_smc(int16x8_t splat) __arm_streaming_compatible {
   // expected-warning at +1 {{builtin call has undefined behaviour when called from a streaming compatible function}}
   return (int16x8_t)__builtin_neon_vqaddq_v((int8x16_t)splat, (int8x16_t)splat, 33);
 }
+
+void incompat_sme_norm(svbool_t pg, void const *ptr) __arm_shared_za {
+  // expected-warning at +1 {{builtin call has undefined behaviour when called from a non-streaming function}}
+  return __builtin_sme_svld1_hor_za128(0, 0, pg, ptr);
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SamTebbs33 wrote:

> nit: returning a `void` value from a `void` function doesn't seem right.

Agreed, I'll fix that.
> Also, is `incompat_sme_norm` testing anything that `incompat_sme_sm` isn't testing?
> Or should this be a test where we'd call a non-streaming SVE/SME builtin from a streaming-function?

Yeah it doesn't look like it is. That would be better!





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