Re: [PATCH] Fixes and workarounds for warnings during autoprofiledbootstrap build

[Martin Jambor <mjambor@suse.cz>]

Hello,

On Wed, May 10 2023, Eugene Rozenfeld via Gcc-patches wrote:
> autoprofiledbootstrap build produces new warnings since inlining decisions
> are different from other builds. This patch contains fixes and workarounds
> for those warnings.
>
> Tested on x86_64-pc-linux-gnu.
>
> gcc/ChangeLog:
>
> 	* config/i386/i386-expand.cc (expand_vec_perm_interleave2): Work around
> 	-Wstringop-overflow false positive during autoprofiledbootstrap
> 	* ipa-devirt.cc (debug_tree_odr_name): Fix for -Wformat-overflow
> 	warning during autoprofiledbootstrap
> 	* lra-eliminations.cc (setup_can_eliminate): Work around
> 	-Wmaybe-uninitialized false positive during autoprofiledbootstrap
> 	* opts-common.cc (candidates_list_and_hint): Work around
> 	-Wstringop-overflow false positive during autoprofiledbootstrap
> 	* tree-ssa-ccp.cc (bit_value_unop): Work around -Wmaybe-uninitialized
> 	false positive during autoprofiledbootstrap
> 	* wide-int.h (wi::copy): Work around -Wmaybe-uninitialized false
> 	positive during autoprofiledbootstrap
> ---
>  gcc/config/i386/i386-expand.cc | 11 +++++++++++
>  gcc/ipa-devirt.cc              |  3 ++-
>  gcc/lra-eliminations.cc        | 11 +++++++++++
>  gcc/opts-common.cc             |  1 +
>  gcc/tree-ssa-ccp.cc            | 11 +++++++++++
>  gcc/wide-int.h                 | 11 +++++++++++
>  6 files changed, 47 insertions(+), 1 deletion(-)
>

[...]

> diff --git a/gcc/ipa-devirt.cc b/gcc/ipa-devirt.cc
> index 819860258d1..36ea266e834 100644
> --- a/gcc/ipa-devirt.cc
> +++ b/gcc/ipa-devirt.cc
> @@ -4033,7 +4033,8 @@ debug_tree_odr_name (tree type, bool demangle)
>        odr = cplus_demangle (odr, opts);
>      }
>  
> -  fprintf (stderr, "%s\n", odr);
> +  if (odr != NULL)
> +    fprintf (stderr, "%s\n", odr);
>  }

I cannot find a call to this debug function on trunk.  How exactly did
this trigger a warning?

In any case, IMHO the function should rather print something that makes
it clear that an odr name could not be obtained rather than printing
nothing.

I also think that if we want to handle the case, we should do it before
also possibly passing odr to demangler.

Thanks,

Martin