[clang] [Sema][AArch64] Emit error for mismatched VLs on streaming mode transitions (PR #159131)

[Sander de Smalen via cfe-commits]

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@@ -0,0 +1,111 @@
+// Case 1: No vscale flags — should only produce warnings
+// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +bf16 -target-feature +sme -target-feature +sme2 -target-feature +sve -Waarch64-sme-attributes -fsyntax-only -verify=expected-noflags %s
+
+// Case 2: Explicit mismatch in vscale flags — should produce errors for 
+// streaming and non-streaming callers
+// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +bf16 -target-feature +sme -target-feature +sme2 -target-feature +sve -Waarch64-sme-attributes -fsyntax-only -mvscale-min=1 -mvscale-max=1 -mvscale-streaming-min=2 -mvscale-streaming-max=2 -verify=expected-flags %s
+
+void sme_streaming_with_vl_arg(__SVInt8_t a) __arm_streaming { } 
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sdesmalen-arm wrote:

nit: you don't necessarily need to define these functions, declaring them is enough. In fact, you could even pass them in as parameters to the functions to clean up the tests a bit more, e.g.:

```
void sme_nonstreaming_calling_streaming(__SVInt8_t v, void (*f)(__SVInt8_t) __arm_streaming) {
  // expected-noflags-warning at +2: ...
  // expected-flags-error at +1: ...
  f(v);
}
```

https://github.com/llvm/llvm-project/pull/159131