[llvm] [AArch64][SME2] Extend getRegAllocationHints for ZPRStridedOrContiguousReg (PR #119865)

[Sander de Smalen via llvm-commits]

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@@ -1099,6 +1099,38 @@ bool AArch64RegisterInfo::getRegAllocationHints(
     const VirtRegMap *VRM, const LiveRegMatrix *Matrix) const {
   const MachineRegisterInfo &MRI = MF.getRegInfo();
 
+  // Since the SVE calling convention preserves registers Z8-Z23, there are no
+  // ZPR2Strided or ZPR4Strided registers which do not overlap with the
+  // callee-saved registers. These will be pushed to the back of the allocation
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sdesmalen-arm wrote:

nit:
```suggestion
  // The SVE calling convention preserves registers Z8-Z23. As a result, there are no
  // ZPR2Strided or ZPR4Strided registers that do not overlap with the
  // callee-saved registers and so by default these will be pushed to the back of the allocation
```

https://github.com/llvm/llvm-project/pull/119865