[Bug rtl-optimization/104778] New: [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324

[Bug rtl-optimization/104778] New: [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

            Bug ID: 104778
           Summary: [12 Regression] ICE in simplify_subreg, at
                    simplify-rtx.cc:7324
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---
            Target: powerpc-*-linux-gnu

Created attachment 52560
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52560&action=edit
Testcase

gcc 12.0.1 20220227 snapshot (g:d1574a9b820f17adb9004255e2018967e9be063b) ICEs
when compiling the attached testcase w/ -mcpu=a2 -Og -g:

% powerpc-e300c3-linux-gnu-gcc-12.0.1 -mcpu=a2 -Og -g -c poy2oawm.c
during RTL pass: vartrack
poy2oawm.c: In function 'foo':
poy2oawm.c:47:1: internal compiler error: in simplify_subreg, at
simplify-rtx.cc:7324
   47 | }
      | ^
0x6ad8e4 simplify_context::simplify_subreg(machine_mode, rtx_def*,
machine_mode, poly_int<1u, unsigned long>)
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/simplify-rtx.cc:7324
0xe76f89 simplify_context::simplify_gen_subreg(machine_mode, rtx_def*,
machine_mode, poly_int<1u, unsigned long>)
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/simplify-rtx.cc:7602
0x11c9e59 simplify_gen_subreg(machine_mode, rtx_def*, machine_mode,
poly_int<1u, unsigned long>)
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/rtl.h:3534
0x11c9e59 vt_expand_loc_callback
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/var-tracking.cc:8524
0x9e432d cselib_expand_value_rtx_1
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/cselib.cc:1848
0x9e4269 cselib_expand_value_rtx_1
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/cselib.cc:1921
0x9e4269 cselib_expand_value_rtx_1
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/cselib.cc:1921
0x9e4269 cselib_expand_value_rtx_1
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/cselib.cc:1921
0x9e5b7e cselib_expand_value_rtx_cb(rtx_def*, bitmap_head*, int, rtx_def*
(*)(rtx_def*, bitmap_head*, int, void*), void*)
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/cselib.cc:1731
0x11c9a23 vt_expand_var_loc_chain
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/var-tracking.cc:8420
0x11ca01d vt_expand_loc_callback
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/var-tracking.cc:8583
0x9e4516 cselib_expand_value_rtx_1
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/cselib.cc:1883
0x9e5b7e cselib_expand_value_rtx_cb(rtx_def*, bitmap_head*, int, rtx_def*
(*)(rtx_def*, bitmap_head*, int, void*), void*)
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/cselib.cc:1731
0x11c9a23 vt_expand_var_loc_chain
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/var-tracking.cc:8420
0x11ca01d vt_expand_loc_callback
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/var-tracking.cc:8583
0x9e5b7e cselib_expand_value_rtx_cb(rtx_def*, bitmap_head*, int, rtx_def*
(*)(rtx_def*, bitmap_head*, int, void*), void*)
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/cselib.cc:1731
0x11c9e22 vt_expand_loc_callback
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/var-tracking.cc:8517
0x9e432d cselib_expand_value_rtx_1
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/cselib.cc:1848
0x9e5b7e cselib_expand_value_rtx_cb(rtx_def*, bitmap_head*, int, rtx_def*
(*)(rtx_def*, bitmap_head*, int, void*), void*)
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/cselib.cc:1731
0x11c9a23 vt_expand_var_loc_chain
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220227/work/gcc-12-20220227/gcc/var-tracking.cc:8420

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |12.0

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Can't reproduce at least with current trunk, both with gcc configured for
powerpc64-linux-gnu and additional -m32, or in a cross to
powerpc-e300c3-linux-gnu with the given options.

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

--- Comment #2 from Arseny Solokha <asolokha at gmx dot com> ---
Created attachment 52586
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52586&action=edit
powerpc-e300c3-linux-gnu-gcc-12.0.1 -mcmpb -Og -g -c k1n69laf.c -Q
--help=target

It still ICEs for we w/ 20220306 snapshot.

  1. It does not ICE w/ -m64.

  2. It does not ICE when I add either -fPIC or -fno-PIC, likewise for -fpic
and -fno-pic.

  3. It ICEs if I replace -mcpu=a2 w/ -mcmpb (i.e.
powerpc-e300c3-linux-gnu-gcc-12.0.1 -mcmpb -Og -g -c poy2oawm.c).

% powerpc-e300c3-linux-gnu-gcc-12.0.1 -v
Using built-in specs.
COLLECT_GCC=powerpc-e300c3-linux-gnu-gcc-12.0.1
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/powerpc-e300c3-linux-gnu/12.0.1/lto-wrapper
Target: powerpc-e300c3-linux-gnu
Configured with:
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220306/work/gcc-12-20220306/configure
--host=x86_64-pc-linux-gnu --target=powerpc-e300c3-linux-gnu
--build=x86_64-pc-linux-gnu --prefix=/usr
--bindir=/usr/x86_64-pc-linux-gnu/powerpc-e300c3-linux-gnu/gcc-bin/12.0.1
--includedir=/usr/lib/gcc/powerpc-e300c3-linux-gnu/12.0.1/include
--datadir=/usr/share/gcc-data/powerpc-e300c3-linux-gnu/12.0.1
--mandir=/usr/share/gcc-data/powerpc-e300c3-linux-gnu/12.0.1/man
--infodir=/usr/share/gcc-data/powerpc-e300c3-linux-gnu/12.0.1/info
--with-gxx-include-dir=/usr/lib/gcc/powerpc-e300c3-linux-gnu/12.0.1/include/g++-v12
--with-python-dir=/share/gcc-data/powerpc-e300c3-linux-gnu/12.0.1/python
--enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt
--disable-werror --with-system-zlib --disable-nls
--disable-libunwind-exceptions --enable-checking=yes --disable-esp
--enable-libstdcxx-time --disable-libstdcxx-pch
--enable-poison-system-directories --with-sysroot=/usr/powerpc-e300c3-linux-gnu
--disable-bootstrap --enable-__cxa_atexit --enable-clocale=gnu
--disable-multilib --disable-fixed-point --enable-targets=all --enable-libgomp
--disable-libssp --disable-libada --disable-cet --disable-systemtap
--enable-valgrind-annotations --disable-vtable-verify --disable-libvtv
--without-zstd --enable-lto --with-isl --disable-isl-version-check
--disable-libsanitizer --enable-default-pie --enable-default-ssp
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.1 20220306 (experimental) (GCC)

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Sorry, still can't reproduce that.
The --help=target output is very similar to yours, just (your -> mine):
-  -mcmodel=                            small
-  -mprioritize-restricted-insns=       1
+  -mprioritize-restricted-insns=       0
-  -mprofile-kernel                     [disabled]
-  -mstack-protector-guard=             tls
+  -mstack-protector-guard=             global

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Ah, I can reproduce with additional -fpie.
We should have never accepted the --enable-default-pie mess, that is a
maintainance nightmare.

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324 since r12-1202-g9080a3bf232978

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[12 Regression] ICE in      |[12 Regression] ICE in
                   |simplify_subreg, at         |simplify_subreg, at
                   |simplify-rtx.cc:7324        |simplify-rtx.cc:7324 since
                   |                            |r12-1202-g9080a3bf232978
                 CC|                            |guihaoc at gcc dot gnu.org

--- Comment #5 from Martin Liška <marxin at gcc dot gnu.org> ---
Started with r12-1202-g9080a3bf232978.

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324 since r12-1202-g9080a3bf232978

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1
                 CC|                            |vmakarov at gcc dot gnu.org

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This seems to go wrong during LRA.
In *.ira we have just:
(debug_insn 352 199 201 19 (var_location:SI D#2 (reg:SI 227)) -1
     (nil))
but then LRA turns that into:
(debug_insn 352 199 201 19 (var_location:SI D#2 (plus:SI (plus:SI (minus:SI
(subreg:SI (reg:HI 130 [ _15 ]) 0)
                (subreg:SI (reg:DI 325 [orig:131 _16 ] [131]) 4))
            (subreg:SI (reg:HI 130 [ _15 ]) 0))
        (zero_extend:SI (subreg:QI (mem/c:SI (reg:SI 304) [0  S4 A32]) 3)))) -1
     (nil))
and later lra_substitute_pseudo turns that into:
(debug_insn 352 199 201 19 (var_location:SI D#2 (plus:SI (plus:SI (minus:SI
(subreg:SI (subreg:HI (reg:SI 270 [ a+4 ]) 2) 0)
                (subreg:SI (reg:DI 325 [orig:131 _16 ] [131]) 4))
            (subreg:SI (subreg:HI (reg:SI 270 [ a+4 ]) 2) 0))
        (zero_extend:SI (subreg:QI (mem/c:SI (reg:SI 304) [0  S4 A32]) 3)))) -1
     (nil))
and later another lra_substitute_pseudo turns that into:
(debug_insn 352 199 201 19 (var_location:SI D#2 (plus:SI (plus:SI (minus:SI
(subreg:SI (const_int 1 [0x1]) 0)
                (subreg:SI (reg:DI 325 [orig:131 _16 ] [131]) 4))
            (subreg:SI (const_int 1 [0x1]) 0))
        (zero_extend:SI (subreg:QI (mem/c:SI (reg:SI 304) [0  S4 A32]) 3)))) -1
     (nil))
I think we can deal in debug_insns with subreg inside of subreg, but we
certainly can't deal with a subreg with VOIDmode operand (ditto for
ZERO_EXTEND/SIGN_EXTEND etc.).

E.g. combine.cc (subst) has:
              if (GET_CODE (x) == SUBREG && CONST_SCALAR_INT_P (new_rtx))
                {
                  machine_mode mode = GET_MODE (x);

                  x = simplify_subreg (GET_MODE (x), new_rtx,
                                       GET_MODE (SUBREG_REG (x)),
                                       SUBREG_BYTE (x));
                  if (! x)
                    x = gen_rtx_CLOBBER (mode, const0_rtx);
                }
              else if (CONST_SCALAR_INT_P (new_rtx)
                       && (GET_CODE (x) == ZERO_EXTEND
                           || GET_CODE (x) == SIGN_EXTEND
                           || GET_CODE (x) == FLOAT
                           || GET_CODE (x) == UNSIGNED_FLOAT))
                {
                  x = simplify_unary_operation (GET_CODE (x), GET_MODE (x),
                                                new_rtx,
                                                GET_MODE (XEXP (x, 0)));
                  if (!x)
                    return gen_rtx_CLOBBER (VOIDmode, const0_rtx);
                }
              /* CONST_INTs shouldn't be substituted into PRE_DEC, PRE_MODIFY
                 etc. arguments, otherwise we can ICE before trying to recog
                 it.  See PR104446.  */
              else if (CONST_SCALAR_INT_P (new_rtx)
                       && GET_RTX_CLASS (GET_CODE (x)) == RTX_AUTOINC)
                return gen_rtx_CLOBBER (VOIDmode, const0_rtx);
              else
                SUBST (XEXP (x, i), new_rtx);
for this (note, RTX_AUTOINC shouldn't appear in debug insns, but the rest can).

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324 since r12-1202-g9080a3bf232978

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 52614
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52614&action=edit
gcc12-pr104778.patch

Untested fix.

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324 since r12-1202-g9080a3bf232978

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #4)
> Ah, I can reproduce with additional -fpie.
> We should have never accepted the --enable-default-pie mess, that is a
> maintainance nightmare.

Well if they had used -freport-bug and attached that preprocessed source,
figuring out the exact options would not have been an issue.

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324 since r12-1202-g9080a3bf232978

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:77eb0461abe61a85f69270048ad81b25b1cc95d6

commit r12-7644-g77eb0461abe61a85f69270048ad81b25b1cc95d6
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Mar 14 14:49:09 2022 +0100

    lra: Fix up debug_p handling in lra_substitute_pseudo [PR104778]

    The following testcase ICEs on powerpc-linux, because lra_substitute_pseudo
    substitutes (const_int 1) into a subreg operand.  First a subreg of subreg
    of a reg appears in a debug insn (which surely is invalid outside of
    debug insns, but in debug insns we allow even what is normally invalid in
    RTL like subregs which the target doesn't like, because either dwarf2out
    is able to handle it, or we just throw away the location expression,
    making some var <optimized out>.

    lra_substitute_pseudo already has some code to deal with specifically
    SUBREG of REG with the REG being substituted for VOIDmode constant,
    but that doesn't cover this case, so the following patch extends
    lra_substitute_pseudo for debug_p mode to treat stuff like e.g.
    combiner's subst function to ensure we don't lose mode which is essential
    for the IL.

    2022-03-14  Jakub Jelinek  <jakub@redhat.com>

            PR debug/104778
            * lra.cc (lra_substitute_pseudo): For debug_p mode, simplify
            SUBREG, ZERO_EXTEND, SIGN_EXTEND, FLOAT or UNSIGNED_FLOAT if
recursive
            call simplified the first operand into VOIDmode constant.

            * gcc.target/powerpc/pr104778.c: New test.

[Bug debug/104778] [12 Regression] ICE in simplify_subreg, at simplify-rtx.cc:7324 since r12-1202-g9080a3bf232978

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104778

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.