re: toolchain/58411: GCC/x86_64 10.5 and 12.4 miscompile GCC/sh3 12.4

[matthew green <mrg%eterna23.net@localhost>]

The following reply was made to PR toolchain/58411; it has been noted by GNATS.

From: matthew green <mrg%eterna23.net@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: toolchain-manager%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
    netbsd-bugs%netbsd.org@localhost
Subject: re: toolchain/58411: GCC/x86_64 10.5 and 12.4 miscompile GCC/sh3 12.4
Date: Wed, 10 Jul 2024 18:16:36 +1000

 looking at config/i386/x86-tune-costs.h nocona, i see that between
 gcc10 and gcc12 this gained some additional things:
 
 struct processor_costs nocona_cost =3D {     =
 
 [ ... ]
   20, 12,                               /* mask->integer and integer->mask=
  moves */
   {4, 4, 4},                            /* cost of loading mask register
                                            in QImode, HImode, SImode.  */
   {4, 4, 4},                            /* cost if storing mask register
                                            in QImode, HImode, SImode.  */
   2,                                    /* cost of moving mask register.  =
 */
 
 which might be related (the mask/int parts?)
 
 for generic_cost, the change is:
 
   6, 6,                                /* mask->integer and integer->mask =
 moves */
   {6, 6, 6},                           /* cost of loading mask register
                                           in QImode, HImode, SImode.  */
   {6, 6, 6},                   /* cost if storing mask register
                                           in QImode, HImode, SImode.  */
   2,                                   /* cost of moving mask register.  *=
 /
 
 
 .mrg.