[PATCH] [PR103017] aarch64:fix redundant check in aut insn generation

Richard Sandiford richard.sandiford@arm.com
Mon Nov 1 11:05:13 GMT 2021


Dan Li via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> During the generation of the epilogue of aarch64(aarch64_expand_epilogue),
> the value of crtl->calls_eh_return does not need to be checked again.
> This value has been checked during aarch64_return_address_signing_enabled.

Ah, yeah, looks like this code became dead with
2bc95be3bb8c8138e2e87c1c11c84bfede989d61.

>
> gcc/ChangeLog:
>
> 	* config/aarch64/aarch64.c (aarch64_expand_epilogue):
> 	* config/aarch64/aarch64.md:
>
> Signed-off-by: Dan Li <ashimida@linux.alibaba.com>

Thanks, applied with the changelog:

	* config/aarch64/aarch64.c (aarch64_expand_epilogue): Remove
	redundant check for calls_eh_return.
	* config/aarch64/aarch64.md (*do_return): Likewise.
> ---
>  gcc/config/aarch64/aarch64.c  | 6 +-----
>  gcc/config/aarch64/aarch64.md | 3 +--
>  2 files changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
> index 699c105a42a..8448e56443c 100644
> --- a/gcc/config/aarch64/aarch64.c
> +++ b/gcc/config/aarch64/aarch64.c
> @@ -9076,13 +9076,9 @@ aarch64_expand_epilogue (bool for_sibcall)
>  	2) The RETAA instruction is not available before ARMv8.3-A, so if we are
>  	   generating code for !TARGET_ARMV8_3 we can't use it and must
>  	   explicitly authenticate.
> -
> -	3) On an eh_return path we make extra stack adjustments to update the
> -	   canonical frame address to be the exception handler's CFA.  We want
> -	   to authenticate using the CFA of the function which calls eh_return.
>      */
>    if (aarch64_return_address_signing_enabled ()
> -      && (for_sibcall || !TARGET_ARMV8_3 || crtl->calls_eh_return))
> +      && (for_sibcall || !TARGET_ARMV8_3))
>      {
>        switch (aarch64_ra_sign_key)
>  	{
> diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
> index 1a39470a1fe..65ee6159d73 100644
> --- a/gcc/config/aarch64/aarch64.md
> +++ b/gcc/config/aarch64/aarch64.md
> @@ -879,8 +879,7 @@ (define_insn "*do_return"
>    {
>      const char *ret = NULL;
>      if (aarch64_return_address_signing_enabled ()
> -	&& (TARGET_PAUTH)
> -	&& !crtl->calls_eh_return)
> +	&& (TARGET_PAUTH))
>        {
>  	if (aarch64_ra_sign_key == AARCH64_KEY_B)
>  	  ret = "retab";


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