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

[Jonathan Thackray via llvm-commits]

================
@@ -371,7 +372,12 @@ void AArch64InstPrinter::printInst(const MCInst *MI, uint64_t Address,
     return;
   }
 
-  if (!PrintAliases || !printAliasInstr(MI, Address, STI, O))
+  // SYSP alias printing is handled explicitly by printSyspAlias above.
+  // Skip the generic alias printer for SYSPxt, because its XSeqPair aliases
+  // are only valid for a subset of SYSP register pairs and can misprint
+  // odd-started regs or xzr,xzr encodings.
+  if (!PrintAliases || Opcode == AArch64::SYSPxt ||
----------------
jthackray wrote:

This comment now obsolete as code has been updated.

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