[llvm] [AArch64] Add CodeGen support for FEAT_CPA (PR #79569)

[Matt Arsenault via llvm-commits]

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@@ -420,6 +420,11 @@ class TargetMachine {
   virtual unsigned getAddressSpaceForPseudoSourceKind(unsigned Kind) const {
     return 0;
   }
+
+  /// True if target has some form of pointer arithmetic checking.
+  /// Helps identify whether pointer arithmetic semantics should be preserved
+  /// for passes such as instruction selection.
+  virtual bool isPtrArithmeticChecked(const Function &F) const { return false; }
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arsenm wrote:

Don't see why this needs to be in TargetMachine. It seems to only depend on the subtarget, so can go directly there? 

https://github.com/llvm/llvm-project/pull/79569