[llvm] [PowerPC] Fix saving of Link Register when using ROP Protect (PR #123101)

[Lei Huang via llvm-commits]

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@@ -908,8 +908,10 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF,
   // in ScratchReg.
   // If the offset can not be encoded into the store instruction, we also have
   // to save LR here.
+  // If we are using ROP Protection we need to save the LR here as we cannot
+  // move the hasst instruction past the point where we get the stack frame.
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lei137 wrote:

nit:
```suggestion
  // move the hashst instruction past the point where we get the stack frame.
```

https://github.com/llvm/llvm-project/pull/123101