Question regarding m68k GCC compiler error

[Lukasz Majewski]

Hi Jeff,

> On Wed, 2020-08-12 at 15:43 +0200, Lukasz Majewski wrote:
> > Dear Community,
> > 
> > During development of following patch [1]
> > I've triggered some interesting error on m68k port:
> > 
> > pthread_cond_wait.c: In function
> > \342\200\230__pthread_cond_wait_common\342\200\231:
> > pthread_cond_wait.c:629:1: error: unable to find a register to
> > spill in class \342\200\230DATA_REGS\342\200\231
> >   629 | }
> >       | ^
> > pthread_cond_wait.c:629:1: error: this is the insn:
> > (jump_insn 485 484 486 27 (parallel [
> >             (set (pc)
> >                 (if_then_else (eq (reg:DI 80 [ _123 ])
> >                         (reg:DI 142 [ s+-4 ]))
> >                     (label_ref 530)
> >                     (pc)))
> >             (clobber (scratch:DI))
> >             (clobber (scratch:SI))
> >         ]) "../sysdeps/nptl/futex-internal.h":552:10 5
> > {cbranchdi4_insn} (expr_list:REG_DEAD (reg:DI 142 [ s+-4 ])
> >         (int_list:REG_BR_PROB 536870916 (nil)))  
> >  -> 530)  
> > pthread_cond_wait.c:629: confused by earlier errors, bailing out
> > 
> > 
> > This error only happens on:
> > 
> > glibcs-m68k-linux-gnu
> > glibcs-m68k-linux-gnu-coldfire
> > glibcs-m68k-linux-gnu-coldfire-soft
> > 
> > Used gcc:
> > gcc version 10.2.1 20200810 [releases/gcc-10 revision
> > f098bc87dca:780e3a9fbae:b5cc5c95664347082100a504710f5ca0467306a5]
> > (GCC)
> > 
> > After poking around it looks like this may be an internal gcc error.
> > 
> > How to reproduce:
> > 1. Please use branch [2]
> > 2. ../src/scripts/build-many-glibcs.py
> > /home/lukma/work/glibc/glibc-many-build --keep failed glibcs
> > m68k-linux-gnu m68k-linux-gnu-coldfire
> > 
> > 
> > 
> > Before I submit a GCC bug - has anybody encountered any similar
> > issue recently for this port?  
> Nope, haven't seen this.
> 
> As Florian noted, this could be a problem with simply using too many
> registers,

Ok.

> but we can't know without a self-contained testcase.

Could you be more specific about above statement? Aren't the above
reproduction steps enough?

> 
> jeff
> >   
> 




Best regards,

Lukasz Majewski

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