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Date: Wed, 11 Jan 2023 10:39:52 +0000
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Subject: Re: [PATCH 10/15 V7] arm: Implement cortex-M return signing address
 codegen
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To: Andrea Corallo <andrea.corallo@arm.com>
Cc: Andrea Corallo via Gcc-patches <gcc-patches@gcc.gnu.org>,
 Richard Earnshaw <Richard.Earnshaw@arm.com>, nd <nd@arm.com>
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From: Richard Earnshaw <Richard.Earnshaw@foss.arm.com>
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On 11/01/2023 09:58, Andrea Corallo via Gcc-patches wrote:
> Richard Earnshaw <Richard.Earnshaw@foss.arm.com> writes:
> 
> [...]
> 
>>
>> Otherwise ok with that change.
>>
>> R.
> 
> Minor respin of this patch addressing the suggestion to have
> 'use_return_insn' return zero when PAC is enabled.
> 
> BR
> 
>    Andrea
> 

+  /* Never use a return instruction when return address signing
+     mechanism is enabled.  */
+  if (arm_current_function_pac_enabled_p ())
+    return 0;
+

I can see what it does.  It would be better to explain why it does: ie 
that return address authentication needs more than one instruction.

OK with that change.