[Bug middle-end/110271] New: [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[Bug middle-end/110271] New: [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110271

            Bug ID: 110271
           Summary: [14 Regression] UICE on pycryptodome-3.17.0 during
                    GIMPLE pass: widening_mul: in gsi_replace, at
                    gimple-iterator.cc:437
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at gcc dot gnu.org
  Target Milestone: ---

Found an ICE on pycryptodome-3.17.0 when building against
r14-1868-ga4df0ce78d6f1b

Reduced example:

// $ cat mont.c.c
unsigned square_sum_hi, square_sum_lo, square_tmp, square_carry, square_tmp2;
void square(unsigned *t, int nw) {
  int i = 0;
  for (; i < nw; i++) {
    square_sum_lo += square_carry;
    square_sum_hi += square_sum_lo < square_carry;
    square_sum_hi += square_tmp = (unsigned long)t > 3;
    square_carry = t[1] + (square_sum_hi < square_tmp);
    square_sum_hi += square_tmp2;
    square_carry += square_sum_hi < square_tmp2;
  }
}
void mont_mult(void) {
  unsigned *t;
  square(t, 9);
}

$ gcc  -fwrapv -O3  -c mont.c.c -o moujnt.o -mavx2 -Wall -Wextra
mont.c.c: In function 'mont_mult':
mont.c.c:15:3: warning: 't' is used uninitialized [-Wuninitialized]
   15 |   square(t, 9);
      |   ^~~~~~~~~~~~
mont.c.c:14:13: note: 't' was declared here
   14 |   unsigned *t;
      |             ^
during GIMPLE pass: widening_mul
mont.c.c:13:6: internal compiler error: in gsi_replace, at
gimple-iterator.cc:437
   13 | void mont_mult(void) {
      |      ^~~~~~~~~
0x6bcf05 gsi_replace(gimple_stmt_iterator*, gimple*, bool)
        ../../source/gcc/gimple-iterator.cc:437
0xe203f4 match_uaddc_usubc
        ../../source/gcc/tree-ssa-math-opts.cc:4880
0xe296f1 after_dom_children
        ../../source/gcc/tree-ssa-math-opts.cc:5581
0x1886063 dom_walker::walk(basic_block_def*)
        ../../source/gcc/domwalk.cc:354
0xe1d76d execute
        ../../source/gcc/tree-ssa-math-opts.cc:5658
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.

$ gcc -v |& unnix
Using built-in specs.
COLLECT_GCC=/<<NIX>>/gcc-14.0.0/bin/gcc
COLLECT_LTO_WRAPPER=/<<NIX>>/gcc-14.0.0/libexec/gcc/x86_64-unknown-linux-gnu/14.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with:
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 99999999 (experimental) (GCC)

[Bug middle-end/110271] [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110271

--- Comment #1 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Created attachment 55330
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55330&action=edit
mont.c.c.orig.xz

In case I reduced it too much mont.c.c.orig.xz is the original preprocessed
file. ICEs with identical compiler options.

[Bug tree-optimization/110271] [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110271

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0
          Component|middle-end                  |tree-optimization

[Bug tree-optimization/110271] [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110271

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

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

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
99% sure it was introduced with r14-1837-g43a3252c42af12 .

[Bug tree-optimization/110271] [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110271

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-06-15
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.

[Bug tree-optimization/110271] [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110271

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The problem is that I thought match_arith_overflow returns true if it replaced
something, but that is not the case, it only returns true for the BIT_NOT_EXPR
case when it removed the stmt.
So, I think the right test for whether match_arith_overflow actually replaced
something is whether gsi_stmt (gsi) == stmt.

[Bug tree-optimization/110271] [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110271

--- Comment #5 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:5b67116a85298bbe358b036d34ad23119cebbdac

commit r14-1895-g5b67116a85298bbe358b036d34ad23119cebbdac
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Jun 16 19:46:36 2023 +0200

    tree-ssa-math-opts: Fix up uaddc/usubc pattern matching [PR110271]

    The following testcase ICEs, because I misremembered what the return value
    from match_arith_overflow is.  It isn't true if __builtin_*_overflow was
    matched, but it is true only in the BIT_NOT_EXPR case if stmt was removed.

    So, if match_arith_overflow matches something, gsi_stmt (gsi) will not
    be stmt and match_uaddc_usubc will be confused and can ICE.

    The following patch fixes it by checking if gsi_stmt (gsi) == stmt,
    in that case we know it is still a PLUS_EXPR/MINUS_EXPR and we can try to
    pattern match it further as UADDC/USUBC.

    2023-06-16  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/110271
            * tree-ssa-math-opts.cc (math_opts_dom_walker::after_dom_children)
            <case PLUS_EXPR>: Ignore return value from match_arith_overflow,
            instead call match_uaddc_usubc only if gsi_stmt (gsi) is still
stmt.

            * gcc.c-torture/compile/pr110271.c: New test.

[Bug tree-optimization/110271] [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110271

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

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

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Should be fixed now.

[Bug tree-optimization/110271] [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110271

--- Comment #7 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
I confirm the fix also fixes pycryptodome-3.17.0 package build. Thank you!

[Bug tree-optimization/110271] [14 Regression] UICE on pycryptodome-3.17.0 during GIMPLE pass: widening_mul: in gsi_replace, at gimple-iterator.cc:437

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110271

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |manuel.lauss at googlemail dot com

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 110296 has been marked as a duplicate of this bug. ***