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

[Mariya Podchishchaeva via cfe-commits]

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@@ -3768,12 +3770,26 @@ void Sema::checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto,
       if (!IsCalleeStreamingCompatible &&
           (CallerFnType == SemaARM::ArmStreamingCompatible ||
            ((CallerFnType == SemaARM::ArmStreaming) ^ IsCalleeStreaming))) {
-        if (IsScalableArg)
-          Diag(Loc, diag::warn_sme_streaming_pass_return_vl_to_non_streaming)
-              << /*IsArg=*/true;
-        if (IsScalableRet)
-          Diag(Loc, diag::warn_sme_streaming_pass_return_vl_to_non_streaming)
-              << /*IsArg=*/false;
+        const LangOptions &LO = getLangOpts();
+        auto VL = LO.VScaleMin * 128;
+        auto SVL = LO.VScaleStreamingMin * 128;
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Fznamznon wrote:

The type is not obvious, could you please not use `auto` here?

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