[clang-tools-extra] [NFC][CodeGen] Create method to clear registers (PR #66958)

[Bill Wendling via cfe-commits]

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@@ -8335,6 +8335,26 @@ bool AArch64InstrInfo::shouldOutlineFromFunctionByDefault(
   return MF.getFunction().hasMinSize();
 }
 
+void AArch64InstrInfo::buildClearRegister(Register Reg, MachineBasicBlock &MBB,
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bwendling wrote:

Yes, in particular I want to call it when deciding when to clear out the register holding the stack protector guard value before exiting the function. It'll probably be during prologue/epilogue mangling, but I think the `TII` is still a nicer place to put it...

https://github.com/llvm/llvm-project/pull/66958