Question regarding m68k GCC compiler error

[Lukasz Majewski]

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?




Links:
[1] -
https://patchwork.ozlabs.org/project/glibc/patch/20200812133014.25766-1-lukma@denx.de/

[2]-
https://github.com/lmajewski/y2038_glibc/tree/y2038_edge-m68k-compiler-issue


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
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