[lldb] [llvm] [AArch64][llvm] Tighten SYSP parsing; don't disassemble invalid encodings (PR #182410)

[Jonathan Thackray via llvm-commits]

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@@ -813,9 +813,15 @@ def XSeqPairsClass   : RegisterClass<"AArch64", [untyped], 64,
                                      (add XSeqPairs)>{
   let Size = 128;
 }
+def SyspPairsClass   : RegisterClass<"AArch64", [untyped], 64,
+                                     (add XSeqPairs, [XZR, XZR])>{
+  let Size = 128;
+  let isAllocatable = 0;
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jthackray wrote:

Added a comment to explain why not.

https://github.com/llvm/llvm-project/pull/182410