[Bug rtl-optimization/114942] New: ICE on valid code at -O1 with "-fno-tree-sra -fno-guess-branch-probability": in extract_constrain_insn, at recog.cc:2713

[Bug rtl-optimization/114942] New: ICE on valid code at -O1 with "-fno-tree-sra -fno-guess-branch-probability": in extract_constrain_insn, at recog.cc:2713

[zhendong.su at inf dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114942

            Bug ID: 114942
           Summary: ICE on valid code at -O1 with "-fno-tree-sra
                    -fno-guess-branch-probability": in
                    extract_constrain_insn, at recog.cc:2713
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

It appears to be a recent regression as it doesn't reproduce with 13.2 and
earlier.

Compiler Explorer: https://godbolt.org/z/av9hr4933

[648] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/15.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--enable-checking=yes --prefix=/local/suz-local/software/local/gcc-trunk
--enable-sanitizers --enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 15.0.0 20240503 (experimental) (GCC)
[649] %
[649] % gcctk -O1 -c -fno-tree-sra -fno-guess-branch-probability small.c
small.c: In function ‘main’:
small.c:21:1: error: insn does not satisfy its constraints:
   21 | }
      | ^
(insn 39 56 57 6 (parallel [
            (set (strict_low_part (reg:QI 2 cx [orig:108 f ] [108]))
                (ior:QI (subreg:QI (zero_extract:HI (reg/v:HI 2 cx [orig:108 f
] [108])
                            (const_int 8 [0x8])
                            (const_int 8 [0x8])) 0)
                    (reg:QI 0 ax [orig:121 _7 ] [121])))
            (clobber (reg:CC 17 flags))
        ]) "small.c":19:7 626 {*iorqi_exthi_1_slp}
     (nil))
during RTL pass: reload
small.c:21:1: internal compiler error: in extract_constrain_insn, at
recog.cc:2713
0x83dea6 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        ../../gcc-trunk/gcc/rtl-error.cc:108
0x83ded2 _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        ../../gcc-trunk/gcc/rtl-error.cc:118
0x83c10c extract_constrain_insn(rtx_insn*)
        ../../gcc-trunk/gcc/recog.cc:2713
0xf55a67 check_rtl
        ../../gcc-trunk/gcc/lra.cc:2189
0xf5aef1 lra(_IO_FILE*, int)
        ../../gcc-trunk/gcc/lra.cc:2610
0xf0b1ff do_reload
        ../../gcc-trunk/gcc/ira.cc:5973
0xf0b1ff execute
        ../../gcc-trunk/gcc/ira.cc:6161
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
[650] %
[650] % cat small.c
extern void a();
struct b {
  char c;
  char d;
} e;
int main() {
  struct b f = e;
  char i = 0;
 L1:
  if (!f.c)
    goto L2;
  if (e.c)
    a();
  else
    return 0;
  f.d = 0;
  i = 1 % ((1 & f.c) - 2);
 L2:
  f.c = ~(i & ~f.d);
  goto L1;
}

[Bug target/114942] [14/15 Regression] ICE on valid code at -O1 with "-fno-tree-sra -fno-guess-branch-probability": in extract_constrain_insn, at recog.cc:2713

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114942

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2024-05-03
   Target Milestone|---                         |14.0
            Summary|ICE on valid code at -O1    |[14/15 Regression] ICE on
                   |with "-fno-tree-sra         |valid code at -O1 with
                   |-fno-guess-branch-probabili |"-fno-tree-sra
                   |ty": in                     |-fno-guess-branch-probabili
                   |extract_constrain_insn, at  |ty": in
                   |recog.cc:2713               |extract_constrain_insn, at
                   |                            |recog.cc:2713
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
            Version|unknown                     |15.0

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed. Looks like it was introduced with r14-5456-gb42a09b258c3ed .

[Bug target/114942] [14/15 Regression] ICE on valid code at -O1 with "-fno-tree-sra -fno-guess-branch-probability": in extract_constrain_insn, at recog.cc:2713

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114942

--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
This is the insn in question:

;; Alternative 1 is needed to work around LRA limitation, see PR82524.
 (define_insn_and_split "*<code>qi_ext<mode>_1_slp"
   [(set (strict_low_part (match_operand:QI 0 "register_operand" "+Q,&Q"))
         (any_logic:QI
           (subreg:QI
             (match_operator:SWI248 3 "extract_operator"
               [(match_operand 2 "int248_register_operand" "Q,Q")
                (const_int 8)
                (const_int 8)]) 0)
           (match_operand:QI 1 "nonimmediate_operand" "0,!qm")))
    (clobber (reg:CC FLAGS_REG))]

When targeting alternative 1, reload should use some other register for operand
2.

[Bug target/114942] [14/15 Regression] ICE on valid code at -O1 with "-fno-tree-sra -fno-guess-branch-probability": in extract_constrain_insn, at recog.cc:2713

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114942

Uroš Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ra

--- Comment #3 from Uroš Bizjak <ubizjak at gmail dot com> ---
Reload starts with:

(insn 39 38 48 6 (parallel [
            (set (strict_low_part (subreg:QI (reg/v:HI 108 [ f ]) 0))
                (ior:QI (subreg:QI (zero_extract:HI (reg/v:HI 108 [ f ])
                            (const_int 8 [0x8])
                            (const_int 8 [0x8])) 0)
                    (reg:QI 121 [ _7 ])))
            (clobber (reg:CC 17 flags))
        ]) "pr114942.c":19:7 626 {*iorqi_exthi_1_slp}
     (expr_list:REG_DEAD (reg:QI 121 [ _7 ])
        (expr_list:REG_UNUSED (reg:CC 17 flags)
            (nil))))

      Choosing alt 1 in insn 39:  (0) &Q  (1) !qm  (2) Q {*iorqi_exthi_1_slp}

and then allocates:

(insn 39 56 57 6 (parallel [
            (set (strict_low_part (reg:QI 2 cx [orig:108 f ] [108]))
                (ior:QI (subreg:QI (zero_extract:HI (reg/v:HI 2 cx [orig:108 f
] [108])
                            (const_int 8 [0x8])
                            (const_int 8 [0x8])) 0)
                    (reg:QI 0 ax [orig:121 _7 ] [121])))
            (clobber (reg:CC 17 flags))
        ]) "pr114942.c":19:7 626 {*iorqi_exthi_1_slp}

not taking into account the earlyclobber of operand 0.

[Bug target/114942] [14/15 Regression] ICE on valid code at -O1 with "-fno-tree-sra -fno-guess-branch-probability": in extract_constrain_insn, at recog.cc:2713

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114942

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|14.0                        |14.2

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 14.1 is being released, retargeting bugs to GCC 14.2.

[Bug target/114942] [14/15 Regression] ICE on valid code at -O1 with "-fno-tree-sra -fno-guess-branch-probability": in extract_constrain_insn, at recog.cc:2713

[vmakarov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114942

--- Comment #5 from Vladimir Makarov <vmakarov at gcc dot gnu.org> ---
I've started to work on this PR.  I hope a patch will be ready on this or the
next week.

[Bug target/114942] [14/15 Regression] ICE on valid code at -O1 with "-fno-tree-sra -fno-guess-branch-probability": in extract_constrain_insn, at recog.cc:2713

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114942

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Vladimir Makarov <vmakarov@gcc.gnu.org>:

https://gcc.gnu.org/g:9585317f0715699197b1313bbf939c6ea3c1ace6

commit r15-364-g9585317f0715699197b1313bbf939c6ea3c1ace6
Author: Vladimir N. Makarov <vmakarov@redhat.com>
Date:   Fri May 10 09:15:50 2024 -0400

    [PR114942][LRA]: Don't reuse input reload reg of inout early clobber
operand

      The insn in question has the same reg in inout operand and input
    operand.  The inout operand is early clobber.  LRA reused input reload
    reg of the inout operand for the input operand which is wrong.  It
    were a good decision if the inout operand was not early clobber one.
    The patch rejects the reuse for the PR test case.

    gcc/ChangeLog:

            PR target/114942
            * lra-constraints.cc (struct input_reload): Add new member
early_clobber_p.
            (get_reload_reg): Add new arg early_clobber_p, don't reuse input
            reload with true early_clobber_p member value, use the arg for new
            element of curr_insn_input_reloads.
            (match_reload): Assign false to early_clobber_p member.
            (process_addr_reg, simplify_operand_subreg, curr_insn_transform):
            Adjust get_reload_reg calls.

    gcc/testsuite/ChangeLog:

            PR target/114942
            * gcc.target/i386/pr114942.c: New.