[llvm] [AArch64] Initial compiler support for SVE unwind on Windows. (PR #138609)

[Benjamin Maxwell via llvm-commits]

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@@ -2757,10 +2853,27 @@ StackOffset AArch64FrameLowering::resolveFrameOffsetReference(
   }
 
   StackOffset ScalableOffset = {};
-  if (UseFP && !(isFixed || isCSR))
-    ScalableOffset = -SVEStackSize;
-  if (!UseFP && (isFixed || isCSR))
-    ScalableOffset = SVEStackSize;
+  bool FPAfterSVECalleeSaves =
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MacDue wrote:

`getFrameIndexReferenceFromSP` also needs to be updated to handle this layout (currently `-pass-remarks-analysis=stack-frame-layout` reports the normal layout). 

https://github.com/llvm/llvm-project/pull/138609