[Bug rtl-optimization/80499] New: gcc ICE on RTL code on x86_64-linux-gnu in "extract_insn"

[helloqirun at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80499

            Bug ID: 80499
           Summary: gcc ICE on RTL code on x86_64-linux-gnu in
                    "extract_insn"
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: helloqirun at gmail dot com
  Target Milestone: ---

The following valid RTL fragment causes an ICE when compiled with the current
gcc trunk on x86_64-linux-gnu in 32-bit mode. The 64-bit mode works fine.

$ gcc-trunk --version
gcc-trunk (GCC) 8.0.0 20170423 (experimental) [trunk revision 247083]
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


$ gcc-trunk -m32 abc1.c
abc1.c: In function ‘test_1’:
abc1.c:20:1: error: unrecognizable insn:
 }
 ^
(insn 2 6 7 2 (set (mem:DI (pre_dec (reg/f:SI 7 sp)) [0  S8 A8])
        (reg/f:SI 6 bp)) -1
     (nil))
abc1.c:20:1: internal compiler error: in extract_insn, at recog.c:2311
0xb19d38 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        ../../gcc/gcc/rtl-error.c:108
0xb19d69 _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        ../../gcc/gcc/rtl-error.c:116
0xae7a6f extract_insn(rtx_insn*)
        ../../gcc/gcc/recog.c:2311
0xae7ac1 extract_insn_cached(rtx_insn*)
        ../../gcc/gcc/recog.c:2201
0x86a3a7 cleanup_subreg_operands(rtx_insn*)
        ../../gcc/gcc/final.c:3152
0x86c551 final_scan_insn(rtx_insn*, _IO_FILE*, int, int, int*)
        ../../gcc/gcc/final.c:2948
0x86da21 final(rtx_insn*, _IO_FILE*, int)
        ../../gcc/gcc/final.c:2051
0x86df09 rest_of_handle_final
        ../../gcc/gcc/final.c:4489
0x86df09 execute
        ../../gcc/gcc/final.c:4562
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.


$ cat abc1.c
int __RTL (startwith ("final")) test_1 ()
{
    (function ""
     (insn-chain
      (block 2
       (edge-from entry )
       (cnote 6 [bb 2] NOTE_INSN_BASIC_BLOCK)
   (cinsn 2 (set (mem:DI (pre_dec(reg sp)) [0  ])
                 (reg bp)) )
      ) (block 3
         (cinsn 3 (parallel [
                       (set (reg ax  )
                        (plus(reg ax )
                         (const_int 4)))
                   ]) )
        ) (block 4
           (edge-from 2)
           (cnote 7 [bb 4] NOTE_INSN_BASIC_BLOCK)
          ) (cbarrier 0) ) )
}