[clang] [llvm] [AArch64][SME] Save VG for unwind info when changing streaming-mode (PR #83301)

[Kerry McLaughlin via cfe-commits]

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@@ -8287,6 +8289,13 @@ AArch64TargetLowering::LowerCall(CallLoweringInfo &CLI,
 
   SDValue InGlue;
   if (RequiresSMChange) {
+
+    if (Subtarget->hasSVE()) {
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kmclaughlin-arm wrote:

I've made changes to `needsAsyncDwarfUnwindInfo` in AArch64MachineFunctionInfo.cpp to always return true if the function has streaming-mode changes. I believe this will ensure we emit the correct information when `-fno-asynchronous-unwind-tables` is specified.

https://github.com/llvm/llvm-project/pull/83301