Re: GCC arc port defaults to -fcommon

[Claudiu Zissulescu <Claudiu.Zissulescu@synopsys.com>]

Hi,

I have quickly tested the next patch, and it looks like everything is alright. In the end we don't really need to temper with fcommon.


diff --git a/gcc/common/config/arc/arc-common.c b/gcc/common/config/arc/arc-common.c
index 6a1190296167..3b36d09997c7 100644
--- a/gcc/common/config/arc/arc-common.c
+++ b/gcc/common/config/arc/arc-common.c
@@ -30,10 +30,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "flags.h"

 static void
-arc_option_init_struct (struct gcc_options *opts)
+arc_option_init_struct (struct gcc_options *opts ATTRIBUTE_UNUSED)
 {
-  opts->x_flag_no_common = 255; /* Mark as not user-initialized.  */
-
   /* Which cpu we're compiling for (ARC600, ARC601, ARC700, ARCv2).  */
   arc_cpu = PROCESSOR_NONE;
 }
diff --git a/gcc/config/arc/arc.c b/gcc/config/arc/arc.c
index 584783f2fb88..5f1d2ffd3995 100644
--- a/gcc/config/arc/arc.c
+++ b/gcc/config/arc/arc.c
@@ -1449,9 +1449,6 @@ arc_override_options (void)
       target_flags |= MASK_NO_SDATA_SET;
     }

-  if (flag_no_common == 255)
-    flag_no_common = !TARGET_NO_SDATA_SET;
-
   /* Check for small data option */
   if (!global_options_set.x_g_switch_value && !TARGET_NO_SDATA_SET)
     g_switch_value = TARGET_LL64 ? 8 : 4;



________________________________
From: Florian Weimer <fweimer@redhat.com>
Sent: Wednesday, July 7, 2021 1:06 PM
To: Richard Biener <richard.guenther@gmail.com>
Cc: GCC Development <gcc@gcc.gnu.org>; Joern Wolfgang Rennecke <gnu@amylaar.uk>; Claudiu Zissulescu <claziss@synopsys.com>
Subject: Re: GCC arc port defaults to -fcommon

* Richard Biener:

> On Wed, Jul 7, 2021 at 11:56 AM Richard Biener
> <richard.guenther@gmail.com> wrote:
>>
>> On Wed, Jul 7, 2021 at 11:00 AM Florian Weimer via Gcc <gcc@gcc.gnu.org> wrote:
>> >
>> > It seems to me that the arc port still defaults to -fcommon, presumably
>> > due to this in gcc/common/config/arc/arc-common.c:
>> >
>> > static void
>> > arc_option_init_struct (struct gcc_options *opts)
>> > {
>> >   opts->x_flag_no_common = 255; /* Mark as not user-initialized.  */
>> >
>> >   /* Which cpu we're compiling for (ARC600, ARC601, ARC700, ARCv2).  */
>> >   arc_cpu = PROCESSOR_NONE;
>> > }
>> >
>> > Is that really necessary?  Is -fno-common broken on arc?
>>
>> It seems arc has -fcommon dependent on !TARGET_NO_SDATA_SET
>> but it should use global_options_set.x_flag_no_common instead of
>> such magic value.
>
> So sth like this (untested):
>
> diff --git a/gcc/common/config/arc/arc-common.c
> b/gcc/common/config/arc/arc-common.c
> index 6a119029616..c8ac7471744 100644
> --- a/gcc/common/config/arc/arc-common.c
> +++ b/gcc/common/config/arc/arc-common.c
> @@ -32,8 +32,6 @@ along with GCC; see the file COPYING3.  If not see
>  static void
>  arc_option_init_struct (struct gcc_options *opts)
>  {
> -  opts->x_flag_no_common = 255; /* Mark as not user-initialized.  */
> -
>    /* Which cpu we're compiling for (ARC600, ARC601, ARC700, ARCv2).  */
>    arc_cpu = PROCESSOR_NONE;
>  }
> diff --git a/gcc/config/arc/arc.c b/gcc/config/arc/arc.c
> index 69f6ae464e1..b9097b11835 100644
> --- a/gcc/config/arc/arc.c
> +++ b/gcc/config/arc/arc.c
> @@ -1440,7 +1440,7 @@ arc_override_options (void)
>    if (flag_pic)
>      target_flags |= MASK_NO_SDATA_SET;
>
> -  if (flag_no_common == 255)
> +  if (!global_options_set.x_flag_no_common)
>      flag_no_common = !TARGET_NO_SDATA_SET;
>
>    /* Check for small data option */

But this means that arc still defaults to -fcommon with this change,
right?

Thanks,
Florian