[Bug target/53735] thumb1 spill failure with -Os
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53735 Richard Earnshaw rearnsha at gcc dot gnu.org changed: What|Removed |Added Status|NEW |RESOLVED Resolution|--- |WONTFIX --- Comment #5 from Richard Earnshaw rearnsha at gcc dot gnu.org --- Realistically, we're never going to be able to fix this. You've tied the compilers hands behind it's back and it's then unable to keep its balance when you give it a push. In Thumb1 code, when optimizing for space, you've got just r0-r6 available in general (r7 is used for the frame pointer). Your source code tries to use all 7 of them (a1[r0]-a4[r3], v1[r4], r5 and v3[r6]). That just leaves r7 (the frame pointer) for the compiler to use for everything, so it's no surprise that things then fall apart.
[Bug target/53735] thumb1 spill failure with -Os
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53735
zhenqiang.chen at linaro dot org changed:
What|Removed |Added
CC||zhenqiang.chen at linaro
||dot org
--- Comment #4 from zhenqiang.chen at linaro dot org 2012-07-26 07:50:25 UTC ---
Root cause: r8-r11 is not available for THUMB1 with -Os.
In function arm_conditional_register_usage (arm.c), you can find the code
if (TARGET_THUMB1 optimize_size)
{
/* When optimizing for size on Thumb-1, it's better not
to use the HI regs, because of the overhead of
stacking them. */
for (regno = FIRST_HI_REGNUM;
regno = LAST_HI_REGNUM; ++regno)
fixed_regs[regno] = call_used_regs[regno] = 1;
}
If removing the code, the result is OK (r8 is used).
[Bug target/53735] thumb1 spill failure with -Os
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53735
zhuolin liu zhuolin.liu at arm dot com changed:
What|Removed |Added
CC||zhuolin.liu at arm dot com
--- Comment #3 from zhuolin liu zhuolin.liu at arm dot com 2012-07-24
09:04:15 UTC ---
simple code
fork() fails to assemble with -mthumb -Os, works with -O2 instead of -Os.
register int aa5 __asm__ (r4) ;
register int aa6 __asm__ (r5) ;
struct pthread
{
int tid;
int pid;
int ss[128];
};
int add_lock;
int fork (void)
{
int * meself = __builtin_thread_pointer () - 1;
if (add_lock !=(int)meself)
{
__lll_lock_wait_private (0);
}
register int __a1 __asm__ (a1)=1;
register int _v3 __asm__ (v3) = 1;
int _v1tmp = (int) (((struct pthread *)__builtin_thread_pointer () -
1)-tid);
register int __a2 __asm__ (a2) =1;
register int __a3 __asm__ (a3) =1;
register int __a4 __asm__ (a4) =1;
register int _v1 __asm__ (v1) = _v1tmp;
__asm__ __volatile__ ( \n : :r (_v3) , r (__a1), r (__a2), r
(__a3), r (__a4), r (_v1) :);
}
[Bug target/53735] thumb1 spill failure with -Os
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53735 Ramana Radhakrishnan ramana at gcc dot gnu.org changed: What|Removed |Added Keywords|assemble-failure| Status|UNCONFIRMED |NEW Last reconfirmed||2012-07-17 Ever Confirmed|0 |1 Known to fail||4.8.0 --- Comment #2 from Ramana Radhakrishnan ramana at gcc dot gnu.org 2012-07-17 09:34:05 UTC --- It's really not an assemble failure. The problem is in the compiler and it looks prima-facie like ICE on valid code.
[Bug target/53735] thumb1 spill failure with -Os
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53735 --- Comment #1 from Bernhard Reutner-Fischer aldot at gcc dot gnu.org 2012-06-20 18:58:06 UTC --- Created attachment 27668 -- http://gcc.gnu.org/bugzilla/attachment.cgi?id=27668 reduced source
