i386: Fix up ix86_abi handling [PR106875]

Hi!

The following testcase fails since my changes to make also
opts_set saved/restored upon function target/optimization changes
(before it has been acting as "has this option be ever explicit
anywhere?").

The problem is that for ix86_abi we depend on the opts_set
value for it in ix86_option_override_internal:
  SET_OPTION_IF_UNSET (opts, opts_set, ix86_abi, DEFAULT_ABI);
but as it is a TargetSave, the backend code is required to
save/restore it manually (it does that) and since gcc 11 also
to save/restore the opts_set bit for it (which isn't done).
We don't do that for various other TargetSave which
ix86_function_specific_{save,restore} saves/restores, but as long
as we never test opts_set for it, it doesn't really matter.
One possible fix would be to introduce some new TargetSave into
which ix86_function_specific_{save,restore} would save/restore a bitmask
of the opts_set bits.  The following patch uses an easier fix, by
making it a TargetVariable instead the saving/restoring is handled
by the generated code.
The differences in options.h are just slight movements on where
*ix86_abi stuff appears in it, ditto for options.cc, the real
differences are just in options-save.cc, where cl_target_option_save
gets:
+  ptr->x_ix86_abi = opts->x_ix86_abi;
...
+  if (opts_set->x_ix86_abi) mask |= HOST_WIDE_INT_1U << 3;
(plus movements of following TargetVariables mask related stuff),
cl_target_option_restore gets:
+  opts->x_ix86_abi = ptr->x_ix86_abi;
...
+  opts_set->x_ix86_abi = static_cast<enum calling_abi>((mask & 1) != 0);
+  mask >>= 1;
plus the movements in other functions too.  So, by it being a
TargetVariable, the only thing that changed is that we don't need to
handle it manually in ix86_function_specific_{save,restore} because it
is handled automatically including the opts_set stuff.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2022-11-28  Jakub Jelinek  <jakub@redhat.com>

	PR target/106875
	* config/i386/i386.opt (x_ix86_abi): Remove TargetSave.
	(ix86_abi): Replace it with TargetVariable.
	* config/i386/i386-options.cc (ix86_function_specific_save,
	ix86_function_specific_restore): Don't save and restore x_ix86_abi.

	* g++.target/i386/pr106875.C: New test.


	Jakub

On Mon, Nov 28, 2022 at 9:46 AM Jakub Jelinek <jakub@redhat.com> wrote:
>
> Hi!
>
> The following testcase fails since my changes to make also
> opts_set saved/restored upon function target/optimization changes
> (before it has been acting as "has this option be ever explicit
> anywhere?").
>
> The problem is that for ix86_abi we depend on the opts_set
> value for it in ix86_option_override_internal:
>   SET_OPTION_IF_UNSET (opts, opts_set, ix86_abi, DEFAULT_ABI);
> but as it is a TargetSave, the backend code is required to
> save/restore it manually (it does that) and since gcc 11 also
> to save/restore the opts_set bit for it (which isn't done).
> We don't do that for various other TargetSave which
> ix86_function_specific_{save,restore} saves/restores, but as long
> as we never test opts_set for it, it doesn't really matter.
> One possible fix would be to introduce some new TargetSave into
> which ix86_function_specific_{save,restore} would save/restore a bitmask
> of the opts_set bits.  The following patch uses an easier fix, by
> making it a TargetVariable instead the saving/restoring is handled
> by the generated code.
> The differences in options.h are just slight movements on where
> *ix86_abi stuff appears in it, ditto for options.cc, the real
> differences are just in options-save.cc, where cl_target_option_save
> gets:
> +  ptr->x_ix86_abi = opts->x_ix86_abi;
> ...
> +  if (opts_set->x_ix86_abi) mask |= HOST_WIDE_INT_1U << 3;
> (plus movements of following TargetVariables mask related stuff),
> cl_target_option_restore gets:
> +  opts->x_ix86_abi = ptr->x_ix86_abi;
> ...
> +  opts_set->x_ix86_abi = static_cast<enum calling_abi>((mask & 1) != 0);
> +  mask >>= 1;
> plus the movements in other functions too.  So, by it being a
> TargetVariable, the only thing that changed is that we don't need to
> handle it manually in ix86_function_specific_{save,restore} because it
> is handled automatically including the opts_set stuff.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2022-11-28  Jakub Jelinek  <jakub@redhat.com>
>
>         PR target/106875
>         * config/i386/i386.opt (x_ix86_abi): Remove TargetSave.
>         (ix86_abi): Replace it with TargetVariable.
>         * config/i386/i386-options.cc (ix86_function_specific_save,
>         ix86_function_specific_restore): Don't save and restore x_ix86_abi.
>
>         * g++.target/i386/pr106875.C: New test.

OK.

Thanks,
Uros.

>
> --- gcc/config/i386/i386.opt.jj 2022-11-14 13:35:46.818988464 +0100
> +++ gcc/config/i386/i386.opt    2022-11-25 17:33:33.325176813 +0100
> @@ -109,8 +109,8 @@ TargetVariable
>  enum cmodel ix86_cmodel = CM_32
>
>  ;; -mabi=
> -TargetSave
> -enum calling_abi x_ix86_abi
> +TargetVariable
> +enum calling_abi ix86_abi = SYSV_ABI
>
>  ;; -masm=
>  TargetSave
> --- gcc/config/i386/i386-options.cc.jj  2022-11-24 10:29:02.965586934 +0100
> +++ gcc/config/i386/i386-options.cc     2022-11-25 17:31:11.803222733 +0100
> @@ -687,7 +687,6 @@ ix86_function_specific_save (struct cl_t
>    ptr->x_recip_mask_explicit = opts->x_recip_mask_explicit;
>    ptr->x_ix86_arch_string = opts->x_ix86_arch_string;
>    ptr->x_ix86_tune_string = opts->x_ix86_tune_string;
> -  ptr->x_ix86_abi = opts->x_ix86_abi;
>    ptr->x_ix86_asm_dialect = opts->x_ix86_asm_dialect;
>    ptr->x_ix86_branch_cost = opts->x_ix86_branch_cost;
>    ptr->x_ix86_dump_tunes = opts->x_ix86_dump_tunes;
> @@ -823,7 +822,6 @@ ix86_function_specific_restore (struct g
>    opts->x_recip_mask_explicit = ptr->x_recip_mask_explicit;
>    opts->x_ix86_arch_string = ptr->x_ix86_arch_string;
>    opts->x_ix86_tune_string = ptr->x_ix86_tune_string;
> -  opts->x_ix86_abi = ptr->x_ix86_abi;
>    opts->x_ix86_asm_dialect = ptr->x_ix86_asm_dialect;
>    opts->x_ix86_branch_cost = ptr->x_ix86_branch_cost;
>    opts->x_ix86_dump_tunes = ptr->x_ix86_dump_tunes;
> --- gcc/testsuite/g++.target/i386/pr106875.C.jj 2022-11-25 17:40:06.680490251 +0100
> +++ gcc/testsuite/g++.target/i386/pr106875.C    2022-11-25 17:39:53.236684603 +0100
> @@ -0,0 +1,5 @@
> +// PR target/106875
> +// { dg-do compile { target { c++11 && lp64 } } }
> +// { dg-options "-O0 -mabi=ms -fabi-version=3 -mcall-ms2sysv-xlogues" }
> +
> +#include "pr101180.C"
>
>         Jakub
>