[Bug tree-optimization/106112] New: wrong code at -Os and above on x86_64-linux-gnu

[Bug tree-optimization/106112] New: wrong code at -Os and above on x86_64-linux-gnu

[zhendong.su at inf dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106112

            Bug ID: 106112
           Summary: wrong code at -Os and above on x86_64-linux-gnu
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

It appears to be a regression from 9.*, and affect 10.* and later. 

[574] % 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/13.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--prefix=/local/suz-local/software/local/gcc-trunk --enable-sanitizers
--enable-languages=c,c++ --disable-werror --enable-multilib --with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.0.0 20220628 (experimental) [master r13-1313-gf9764ea128c] (GCC) 
[575] % 
[575] % gcctk -O1 small.c; ./a.out
[576] % 
[576] % gcctk -Os small.c
[577] % ./a.out
Aborted
[578] % 
[578] % cat small.c
int a = 5, b, c, d;
unsigned long e = 20862985922;
int main() {
  unsigned f = 4294967292;
  e = e | f;
  c = -1 % ((~f ^ 4294967292) - (e - d));
  b = ~-~e % ~-d;
  if (b)
    a = 0;
  if (a < 1)
    __builtin_abort();
  return 0;
}

[Bug tree-optimization/106112] wrong code at -Os and above on x86_64-linux-gnu

[zhendong.su at inf dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106112

--- Comment #1 from Zhendong Su <zhendong.su at inf dot ethz.ch> ---
Compiler Explorer: https://godbolt.org/z/v6qY9d6q6

[Bug tree-optimization/106112] [10/11/12/13 Regression] wrong code at -Os and above on x86_64-linux-gnu since r10-2711-g3ed01d5408045d80

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106112

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-06-28
                 CC|                            |marxin at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
            Version|unknown                     |13.0
            Summary|wrong code at -Os and above |[10/11/12/13 Regression]
                   |on x86_64-linux-gnu         |wrong code at -Os and above
                   |                            |on x86_64-linux-gnu since
                   |                            |r10-2711-g3ed01d5408045d80
   Target Milestone|---                         |10.5
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> ---
Started with r10-2711-g3ed01d5408045d80.

[Bug tree-optimization/106112] [10/11/12/13 Regression] wrong code at -Os and above on x86_64-linux-gnu since r10-2711-g3ed01d5408045d80

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106112

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 #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
  <bb 2> [local count: 1073741824]:
  e.0_1 = e;
  _2 = e.0_1 | 4294967292;
  e = _2;
  d.1_3 = d;
  _4 = (long unsigned int) d.1_3;
-  # RANGE [2147483647, 6442450942] NONZERO 8589934591
+  # RANGE ~[2147483647, 18446744071562067967]
  _10 = _4 + 4294967295;
  _7 = _10 - _2;
  _8 = 18446744073709551615 % _7;
  _9 = (int) _8;
  c = _9;
  _11 = 18446744073709551614 - _2;
-  _13 = d.1_3 + -1;
-  # RANGE ~[2147483647, 18446744071562067967]
-  _14 = (long unsigned int) _13;
-  _15 = _11 % _14;
+  _15 = _11 % _10;

is the key change, replacing (unsigned long)(intvar + -1) with (unsigned
long)intvar + 4294967295

It looks like

  /* For constants simply extend it.  */
  if (TREE_CODE (op) == INTEGER_CST)
    return wide_int_to_tree (wide_type, wi::to_wide (op));

doesn't sign-extend the -1 from int to unsigned log.  Using wi::to_widest
does and fixes the testcase.

[Bug tree-optimization/106112] [10/11/12/13 Regression] wrong code at -Os and above on x86_64-linux-gnu since r10-2711-g3ed01d5408045d80

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106112

--- Comment #4 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:2dbb45d6dc0d20dc159b3d8e27ebb6825074827a

commit r13-1341-g2dbb45d6dc0d20dc159b3d8e27ebb6825074827a
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Jun 28 13:57:29 2022 +0200

    tree-optimization/106112 - fix CSE from wider operation

    The following fixes a mistake in looking up an extended operand
    in the CSE of a truncated operation.

    2022-06-28  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/106112
            * tree-ssa-sccvn.cc (valueized_wider_op): Properly extend
            a constant operand according to its type.

            * gcc.dg/torture/pr106112.c: New testcase.

[Bug tree-optimization/106112] [10/11/12 Regression] wrong code at -Os and above on x86_64-linux-gnu since r10-2711-g3ed01d5408045d80

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106112

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |12.1.0
            Summary|[10/11/12/13 Regression]    |[10/11/12 Regression] wrong
                   |wrong code at -Os and above |code at -Os and above on
                   |on x86_64-linux-gnu since   |x86_64-linux-gnu since
                   |r10-2711-g3ed01d5408045d80  |r10-2711-g3ed01d5408045d80
      Known to work|                            |13.0
           Priority|P3                          |P2
           Keywords|                            |wrong-code

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed on trunk sofar.

[Bug tree-optimization/106112] [10/11/12 Regression] wrong code at -Os and above on x86_64-linux-gnu since r10-2711-g3ed01d5408045d80

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106112

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:854ab8be5d9ddfc5b4d57a5c040d1811a89fbe4f

commit r12-8582-g854ab8be5d9ddfc5b4d57a5c040d1811a89fbe4f
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Jun 28 13:57:29 2022 +0200

    tree-optimization/106112 - fix CSE from wider operation

    The following fixes a mistake in looking up an extended operand
    in the CSE of a truncated operation.

    2022-06-28  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/106112
            * tree-ssa-sccvn.cc (valueized_wider_op): Properly extend
            a constant operand according to its type.

            * gcc.dg/torture/pr106112.c: New testcase.

    (cherry picked from commit 2dbb45d6dc0d20dc159b3d8e27ebb6825074827a)

[Bug tree-optimization/106112] [10/11 Regression] wrong code at -Os and above on x86_64-linux-gnu since r10-2711-g3ed01d5408045d80

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106112

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:b7878f05553bcf569a987dff8a7ef8b045b8d26c

commit r11-10303-gb7878f05553bcf569a987dff8a7ef8b045b8d26c
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Jun 28 13:57:29 2022 +0200

    tree-optimization/106112 - fix CSE from wider operation

    The following fixes a mistake in looking up an extended operand
    in the CSE of a truncated operation.

    2022-06-28  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/106112
            * tree-ssa-sccvn.c (valueized_wider_op): Properly extend
            a constant operand according to its type.

            * gcc.dg/torture/pr106112.c: New testcase.

    (cherry picked from commit 2dbb45d6dc0d20dc159b3d8e27ebb6825074827a)

[Bug tree-optimization/106112] [10 Regression] wrong code at -Os and above on x86_64-linux-gnu since r10-2711-g3ed01d5408045d80

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106112

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:983d87530d8efbae6b5f4973c52edd1071d26add

commit r10-11035-g983d87530d8efbae6b5f4973c52edd1071d26add
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Jun 28 13:57:29 2022 +0200

    tree-optimization/106112 - fix CSE from wider operation

    The following fixes a mistake in looking up an extended operand
    in the CSE of a truncated operation.

    2022-06-28  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/106112
            * tree-ssa-sccvn.c (valueized_wider_op): Properly extend
            a constant operand according to its type.

            * gcc.dg/torture/pr106112.c: New testcase.

    (cherry picked from commit 2dbb45d6dc0d20dc159b3d8e27ebb6825074827a)

[Bug tree-optimization/106112] [10 Regression] wrong code at -Os and above on x86_64-linux-gnu since r10-2711-g3ed01d5408045d80

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106112

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |10.4.0
      Known to work|                            |10.4.1
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.