Re: [PATCH] opts: fix -gtoggle + optimize attribute

[Richard Biener <richard.guenther@gmail.com>]

On Mon, Feb 28, 2022 at 10:03 AM Martin Liška <mliska@suse.cz> wrote:
>
> Note -fvar-tracking is enabled automatically with OPT_LEVELS_1_PLUS and
> so we need to drop it if we are called from optimize attribute and the
> option is unset.
>
> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>
> Ready to be installed?
> Thanks,
> Martin
>
>         PR middle-end/104381
>
> gcc/ChangeLog:
>
>         * opts.cc (finish_options): If debug info is disabled
>         (debug_info_level) and -fvar-tracking is unset, disable it.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.dg/pr104381.c: New test.
> ---
>   gcc/opts.cc                     | 49 +++++++++++++++++++--------------
>   gcc/testsuite/gcc.dg/pr104381.c | 20 ++++++++++++++
>   2 files changed, 48 insertions(+), 21 deletions(-)
>   create mode 100644 gcc/testsuite/gcc.dg/pr104381.c
>
> diff --git a/gcc/opts.cc b/gcc/opts.cc
> index 19c68aed065..2370bb0aafe 100644
> --- a/gcc/opts.cc
> +++ b/gcc/opts.cc
> @@ -1302,6 +1302,34 @@ finish_options (struct gcc_options *opts, struct gcc_options *opts_set,
>       SET_OPTION_IF_UNSET (opts, opts_set, flag_vect_cost_model,
>                          VECT_COST_MODEL_CHEAP);
>
> +  if (flag_gtoggle)
> +    {
> +      /* Make sure to process -gtoggle only once.  */
> +      flag_gtoggle = false;
> +      if (debug_info_level == DINFO_LEVEL_NONE)
> +       {
> +         debug_info_level = DINFO_LEVEL_NORMAL;
> +
> +         if (write_symbols == NO_DEBUG)
> +           write_symbols = PREFERRED_DEBUGGING_TYPE;
> +       }
> +      else
> +       debug_info_level = DINFO_LEVEL_NONE;
> +    }
> +
> +  if (!OPTION_SET_P (debug_nonbind_markers_p))
> +    debug_nonbind_markers_p
> +      = (optimize
> +        && debug_info_level >= DINFO_LEVEL_NORMAL
> +        && dwarf_debuginfo_p ()
> +        && !(flag_selective_scheduling || flag_selective_scheduling2));
> +
> +  /* Note -fvar-tracking is enabled automatically with OPT_LEVELS_1_PLUS and
> +     so we need to drop it if we are called from optimize attribute.  */
> +  if (debug_info_level < DINFO_LEVEL_NORMAL
> +      && !OPTION_SET_P (flag_var_tracking))
> +    flag_var_tracking = false;
> +

I think moving flag_gtoggle handling before the flag_syntax_only handling
is a good thing.  But I don't quite understand the flag_var_tracking disabling
or how it worked before.  At least I think you want to check for
debug_info_level == NONE, no?  Why should DINFO_LEVEL_TERSE be
special?

>     /* One could use EnabledBy, but it would lead to a circular dependency.  */
>     if (!OPTION_SET_P (flag_var_tracking_uninit))
>        flag_var_tracking_uninit = flag_var_tracking;
> @@ -1328,27 +1356,6 @@ finish_options (struct gcc_options *opts, struct gcc_options *opts_set,
>         profile_flag = 0;
>       }
>
> -  if (flag_gtoggle)
> -    {
> -      /* Make sure to process -gtoggle only once.  */
> -      flag_gtoggle = false;
> -      if (debug_info_level == DINFO_LEVEL_NONE)
> -       {
> -         debug_info_level = DINFO_LEVEL_NORMAL;
> -
> -         if (write_symbols == NO_DEBUG)
> -           write_symbols = PREFERRED_DEBUGGING_TYPE;
> -       }
> -      else
> -       debug_info_level = DINFO_LEVEL_NONE;
> -    }
> -
> -  if (!OPTION_SET_P (debug_nonbind_markers_p))
> -    debug_nonbind_markers_p
> -      = (optimize
> -        && debug_info_level >= DINFO_LEVEL_NORMAL
> -        && dwarf_debuginfo_p ()
> -        && !(flag_selective_scheduling || flag_selective_scheduling2));
>
>     diagnose_options (opts, opts_set, loc);
>   }
> diff --git a/gcc/testsuite/gcc.dg/pr104381.c b/gcc/testsuite/gcc.dg/pr104381.c
> new file mode 100644
> index 00000000000..a3aec919bee
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr104381.c
> @@ -0,0 +1,20 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -g -gtoggle -fdump-tree-optimized" } */
> +
> +int foo (int x)
> +{
> +  int tem = x + 1;
> +  int tem2 = tem - 1;
> +  return tem2;
> +}
> +
> +int
> +__attribute__((optimize("no-tree-pre")))
> +bar (int x)
> +{
> +  int tem = x + 1;
> +  int tem2 = tem - 1;
> +  return tem2;
> +}
> +
> +// { dg-final { scan-tree-dump-not "DEBUG " "optimized" } }
> --
> 2.35.1
>