[Bug middle-end/112444] New: [14 regression] ICE when buliding libqmi (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85)

[Bug middle-end/112444] New: [14 regression] ICE when buliding libqmi (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

            Bug ID: 112444
           Summary: [14 regression] ICE when buliding libqmi (internal
                    compiler error: tree check: expected class ‘type’,
                    have ‘exceptional’ (error_mark) in
                    useless_type_conversion_p, at gimple-expr.cc:85)
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sjames at gcc dot gnu.org
  Target Milestone: ---

Created attachment 56534
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56534&action=edit
meson-generated_.._qmi-pbm.c.i.xz

Originally reported downstream in Gentoo by Toralf Förster at
https://bugs.gentoo.org/917037.

Seems to need -ftrivial-auto-var-init=zero.
```
# x86_64-pc-linux-gnu-gcc -Isrc/libqmi-glib/generated/libqmi-glib-generated.a.p
-Isrc/libqmi-glib/generated -I../libqmi-1.32.4/src/libqmi-glib/generated -I.
-I../libqmi-1.32.4 -Isrc/libqmi-glib -I../libqmi-1.32.4/src/libqmi-glib
-I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include
-I/usr/lib64/libffi/include -I/usr/include/libmount -I/usr/include/blkid
-I/usr/include/libqrtr-glib -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64
-Wall -Winvalid-pch -Wextra -std=gnu89 -DHAVE_CONFIG_H -Wno-unused-parameter
-Wno-cast-function-type -Wno-packed -O3 -pipe -march=native
-fno-diagnostics-color -fPIC -pthread
-DGLIB_VERSION_MIN_REQUIRED=GLIB_VERSION_2_56
-DGLIB_VERSION_MAX_ALLOWED=GLIB_VERSION_2_56
-DGLIB_DISABLE_DEPRECATION_WARNINGS -DLIBQMI_GLIB_COMPILATION
'-DG_LOG_DOMAIN="Qmi"' -Wno-unused-function -MD -MQ
src/libqmi-glib/generated/libqmi-glib-generated.a.p/meson-generated_.._qmi-pbm.c.o
-MF
src/libqmi-glib/generated/libqmi-glib-generated.a.p/meson-generated_.._qmi-pbm.c.o.d
-o
src/libqmi-glib/generated/libqmi-glib-generated.a.p/meson-generated_.._qmi-pbm.c.o
-c src/libqmi-glib/generated/qmi-pbm.c -ftrivial-auto-var-init=zero
during GIMPLE pass: fre
src/libqmi-glib/generated/qmi-pbm.c: In function
‘message_get_all_capabilities_get_tlv_printable’:
src/libqmi-glib/generated/qmi-pbm.c:3934:1: internal compiler error: tree
check: expected class ‘type’, have ‘exceptional’ (error_mark) in
useless_type_conversion_p, at gimple-expr.cc:85
 3934 | message_get_all_capabilities_get_tlv_printable (
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0x560e0a0b792f tree_class_check_failed(tree_node const*, tree_code_class, char
const*, int, char const*)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20231105/gcc-14-20231105/gcc/tree.cc:8999
0x560e0924e52a tree_class_check(tree_node*, tree_code_class, char const*, int,
char const*)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20231105/gcc-14-20231105/gcc/tree.h:3753
0x560e0924e52a useless_type_conversion_p(tree_node*, tree_node*)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20231105/gcc-14-20231105/gcc/gimple-expr.cc:85
0x560e0a9c8534 verify_gimple_assign_single
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20231105/gcc-14-20231105/gcc/tree-cfg.cc:4593
0x560e0aa84d20 verify_gimple_in_cfg(function*, bool, bool)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20231105/gcc-14-20231105/gcc/tree-cfg.cc:5582
0x560e0a8f7f9c execute_function_todo
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20231105/gcc-14-20231105/gcc/passes.cc:2088
0x560e0a8f7f9c do_per_function
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20231105/gcc-14-20231105/gcc/passes.cc:1687
0x560e0a8f7f9c execute_todo
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20231105/gcc-14-20231105/gcc/passes.cc:2142
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://bugs.gentoo.org/> for instructions.
```

'gcc -c meson-generated_.._qmi-pbm.c.i -O3 -ftrivial-auto-var-init=zero' is
enough for me to reproduce.

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

--- Comment #1 from Sam James <sjames at gcc dot gnu.org> ---
Created attachment 56535
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56535&action=edit
reduced.i

cvise popped this out, I haven't tried to prettify it by hand at all as heading
out now.

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 56543
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56543&action=edit
little more reduced

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #56543|0                           |1
        is obsolete|                            |

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 56544
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56544&action=edit
with no warnings

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
           Keywords|                            |ice-on-valid-code
             Status|UNCONFIRMED                 |NEW
   Target Milestone|---                         |14.0
   Last reconfirmed|                            |2023-11-09

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
```
  <bb 3> [local count: 57140633]:
  # ivtmp_62 = PHI <44(2), ivtmp_72(8)>
  _7 = .DEFERRED_INIT (1, 2, &"tmp"[0]);
...
  <bb 5> [local count: 57140633]:
  # _59 = PHI <_7(3), _54(4)>

  <bb 6> [local count: 877722739]:
  # ivtmp_8 = PHI <444(5), ivtmp_63(7)>
  tmp = _59;
```

defining statement of _54 is nowhere to be found.

Note this ICEs still even with -fno-checking

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note the 2 tmp variables need to be named the same. Otherwise fre won't merge
the 2 ".DEFERRED_INIT (1, 2, &"tmp"[0]);" .

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85) since r14-4405-gb583a2940af90d

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

Sam James <sjames at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu.org
            Summary|[14 regression] ICE when    |[14 regression] ICE when
                   |buliding libqmi with -O3    |buliding libqmi with -O3
                   |-ftrivial-auto-var-init=zer |-ftrivial-auto-var-init=zer
                   |o (internal compiler error: |o (internal compiler error:
                   |tree check: expected class  |tree check: expected class
                   |‘type’, have ‘exceptional’  |‘type’, have ‘exceptional’
                   |(error_mark) in             |(error_mark) in
                   |useless_type_conversion_p,  |useless_type_conversion_p,
                   |at gimple-expr.cc:85)       |at gimple-expr.cc:85) since
                   |                            |r14-4405-gb583a2940af90d

--- Comment #6 from Sam James <sjames at gcc dot gnu.org> ---
b583a2940af90d03f535648fef111cb158933f7d is the first bad commit
commit b583a2940af90d03f535648fef111cb158933f7d
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Oct 4 15:25:33 2023 +0200

    Avoid left around copies when value-numbering BBs

    The following makes sure to treat values whose definition we didn't
    visit as available since those by definition must dominate the entry
    of the region.  That avoids unpropagated copies after if-conversion
    and resulting SLP discovery fails (which doesn't handle plain copies).

            * tree-ssa-sccvn.cc (rpo_elim::eliminate_avail): Not
            visited value numbers are available itself.

 gcc/tree-ssa-sccvn.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
bisect found first bad commit

i.e. r14-4405-gb583a2940af90d

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85) since r14-4405-gb583a2940af90d

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
I will have a look.

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85) since r14-4405-gb583a2940af90d

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
OK, so the reason is that we value-number tmp_46 in

<bb 3> [local count: 482002707]:
if (0 != 0)
  goto <bb 5>; [33.00%]
else
  goto <bb 4>; [67.00%]

<bb 4> [local count: 322941815]:
tmp_5 = .DEFERRED_INIT (1, 2, &"tmp"[0]);
...
goto <bb 6>;

<bb 5> [local count: 159060893]:
...
tmp_2 = .DEFERRED_INIT (1, 2, &"tmp"[0]);
...

tmp_46 = PHI <tmp_5(4), tmp_2(5)>

to tmp_2 because we use ssa_undefined_value_p () to check whether we are
dealing with an undefined value.  And that returns true for tmp_5.  This
makes us pick tmp_2 which we treat as VARYING since we didn't visit it
and we don't trust the not-executable state of its incoming edge (a missed
optimization, guess I can look at that as well).  tmp_2 is also considered
undefined.  We then have

  /* If we saw only undefined values and VN_TOP use one of the
     undefined values.  */
  else if (sameval == VN_TOP)
    result = seen_undef ? seen_undef : sameval;

and "one of" puts us in an unlucky situation here.

I do have a sensible fix around this I think.

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85) since r14-4405-gb583a2940af90d

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

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

https://gcc.gnu.org/g:8ebcea91e24964ec52ca2caf9f8585f3a785f7d5

commit r14-5276-g8ebcea91e24964ec52ca2caf9f8585f3a785f7d5
Author: Richard Biener <rguenther@suse.de>
Date:   Thu Nov 9 09:41:10 2023 +0100

    tree-optimization/112444 - avoid bougs PHI value-numbering

    With .DEFERRED_INIT ssa_undefined_value_p () can return true for
    values we did not visit (because they proved unreachable) but
    are not .VN_TOP.  Avoid using those as value which, because they
    are not visited, are assumed to be defined outside of the region.

            PR tree-optimization/112444
            * tree-ssa-sccvn.cc (visit_phi): Avoid using not visited
            defs as undefined vals.

            * gcc.dg/torture/pr112444.c: New testcase.

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85) since r14-4405-gb583a2940af90d

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444

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

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

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.

[Bug middle-end/112444] [14 regression] ICE when buliding libqmi with -O3 -ftrivial-auto-var-init=zero (internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85) since r14-4405-gb583a2940af90d

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112444
Bug 112444 depends on bug 112939, which changed state.

Bug 112939 Summary: [14 Regression] ICE: verify_ssa failed with -O -ftrivial-auto-var-init=zero
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112939

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