Consider
struct s {
unsigned a : 1;
};
int
foo (struct s *p, int b, int c, int d)
{
p->a = 0;
return b;
}
"./cc1 -quiet -mthumb -fPIC min.c" gives me
min.c: In function 'foo':
min.c:10: internal compiler error: in thumb_find_work_register, at
config/arm/arm.c:3280
Please submit a full bug report,
with preprocessed source if appropriate.
See <for instructions.
This testcase is reduced from libiberty/regex.c.

Additional Comments From pinskia at gcc dot gnu dot org 2005-08-19 02:40
/* Something went wrong - thumb_compute_save_reg_mask()
should have arranged for a suitable register to be pushed. */
gcc_unreachable ();

Additional Comments From pinskia at gcc dot gnu dot org 2005-08-19 02:53
Seems like it was caused by:

PR target/23355
* arm.c (thumb_compute_save_reg_mask): Use similar logic to
to determine when the PIC register
must be saved.

Confirmed, it worked a little bit ago. Also it fails on arm-linux-gnu.

Additional Comments From kazu at gcc dot gnu dot org 2005-08-19 03:11
In fact, reverting Richard Earnshaw's patch

2005-08-15 Richard Earnshaw <richard.earnshaw (AT) arm (DOT) com>

PR target/23355
* arm.c (thumb_compute_save_reg_mask): Use similar logic to
to determine when the PIC register
must be saved.

fixes the problem (although simply reverting the patch is probably not a
good idea because it's supposed to fix PR 23355).

Additional Comments From rearnsha at gcc dot gnu dot org 2005-08-19 09:44
K. I think I understand what's failing here. Testing patch.

Additional Comments From cvs-commit at gcc dot gnu dot org 2005-08-19 13:17
Subject: Bug 23473

CVSRT:/cvs/gcc
Module name:gcc
Changes by:rearnsha (AT) gcc (DOT) gnu.org2005-08-19 13:17:04

Modified files:
gcc : ChangeLog
gcc/config/arm : arm.c arm-protos.h

Log message:
PR target/23473
* arm.md (arm_load_pic_register): Change argument to the mask of
saved registers. Call thumb_find_work_register if we need a
scratch register on Thumb.
(arm_expand_prologue): Pass empty register set to
arm_load_pic_register.
(thumb_expand_prologue): Pass live_regs_mask directly to
arm_load_pic_register.
* arm-protos.h (arm_load_pic_register): Update prototype.

Patches:

Additional Comments From rearnsha at gcc dot gnu dot org 2005-08-19 13:17
Fixed.