[Bug rtl-optimization/66412] [5/6 Regression] ICE on valid code at -O2 and -O3 with -g enabled in simplify_subreg, at simplify-rtx.c:5748

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66412

--- Comment #6 from Uroš Bizjak <ubizjak at gmail dot com> ---
Please note that combine already calls propagate_for_debug with wrong i1src:

reakpoint 3, internal_error (gmsgid=gmsgid@entry=0x1622837 "in %s, at %s:%d")
at /home/uros/gcc-svn/trunk/gcc/diagnostic.c:1266
1266    {
(gdb) f 6
#6  0x000000000103276c in try_combine (i3=i3@entry=0x7ffff171c580,
i2=<optimized out>, i2@entry=0x7ffff171c540, i1=<optimized out>, i0=<optimized
out>, i0@entry=0x0, 
    new_direct_jump_p=new_direct_jump_p@entry=0x7fffffffd95c,
last_combined_insn=last_combined_insn@entry=0x7ffff171c580) at
/home/uros/gcc-svn/trunk/gcc/combine.c:4386
4386                                   this_basic_block);
(gdb) list
4381          {
4382            LOG_LINKS (i1) = NULL;
4383            REG_NOTES (i1) = 0;
4384            if (MAY_HAVE_DEBUG_INSNS)
4385              propagate_for_debug (i1, last_combined_insn, i1dest, i1src,
4386                                   this_basic_block);
4387            SET_INSN_DELETED (i1);
4388          }
4389
4390        if (i0)
(gdb) p debug_rtx (i1dest)
(reg:SI 94 [ D.1784 ])
$74 = void
(gdb) p debug_rtx (i1src)
(eq:QI (reg:CCZ 17 flags)
    (const_int 0 [0]))