[Bug c/58385] New: likely wrong code bug

[Bug c/58385] New: likely wrong code bug

[regehr at cs dot utah.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58385

            Bug ID: 58385
           Summary: likely wrong code bug
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: regehr at cs dot utah.edu
                CC: chenyang at cs dot utah.edu

regehr@john-home ~/z/reduce/r112 $ gcc -O0 small.c ; ./a.out
0
regehr@john-home ~/z/reduce/r112 $ gcc -O1 small.c ; ./a.out
1
regehr@john-home ~/z/reduce/r112 $ cat small.c
int printf(const char *, ...);
int x0, x1 = 1;
int x2() {
  x1 = 0;
  return 0;
}

int main() {
  ((0 || x0) & x2() >= 0) <= 1 && 1;
  printf("%d\n", x1);
  return 0;
}
regehr@john-home ~/z/reduce/r112 $ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/home/regehr/z/compiler-install/gcc-r202470-install/libexec/gcc/x86_64-unknown-linux-gnu/4.9.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: /home/regehr/z/compiler-source/gcc/configure
--prefix=/home/regehr/z/compiler-install/gcc-r202470-install
--enable-languages=c,c++ --disable-multilib
Thread model: posix
gcc version 4.9.0 20130910 (experimental) (GCC)

[Bug middle-end/58385] likely wrong code bug

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58385

Marc Glisse <glisse at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-09-10
     Ever confirmed|0                           |1

--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> ---
Confirmed, already in 4.6. Somewhere in fold_range_test we forget to check for
side effects.

[Bug middle-end/58385] [4.7/4.8/4.9 Regression] likely wrong code bug

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58385

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org
   Target Milestone|---                         |4.7.4
            Summary|likely wrong code bug       |[4.7/4.8/4.9 Regression]
                   |                            |likely wrong code bug

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r145254.

[Bug middle-end/58385] [4.7/4.8/4.9 Regression] likely wrong code bug

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58385

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

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

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 30795
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30795&action=edit
gcc49-pr58385.patch

Untested fix.

[Bug middle-end/58385] [4.7/4.8/4.9 Regression] likely wrong code bug

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58385

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Wed Sep 11 11:35:51 2013
New Revision: 202494

URL: http://gcc.gnu.org/viewcvs?rev=202494&root=gcc&view=rev
Log:
    PR tree-optimization/58385
    * fold-const.c (build_range_check): If both low and high are NULL,
    use omit_one_operand_loc to preserve exp side-effects.

    * gcc.c-torture/execute/pr58385.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/pr58385.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/fold-const.c
    trunk/gcc/testsuite/ChangeLog

[Bug middle-end/58385] [4.7/4.8/4.9 Regression] likely wrong code bug

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58385

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Wed Sep 11 12:17:47 2013
New Revision: 202495

URL: http://gcc.gnu.org/viewcvs?rev=202495&root=gcc&view=rev
Log:
    PR tree-optimization/58385
    * fold-const.c (build_range_check): If both low and high are NULL,
    use omit_one_operand_loc to preserve exp side-effects.

    * gcc.c-torture/execute/pr58385.c: New test.

Added:
    branches/gcc-4_8-branch/gcc/testsuite/gcc.c-torture/execute/pr58385.c
Modified:
    branches/gcc-4_8-branch/gcc/ChangeLog
    branches/gcc-4_8-branch/gcc/fold-const.c
    branches/gcc-4_8-branch/gcc/testsuite/ChangeLog

[Bug middle-end/58385] [4.7 Regression] likely wrong code bug

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58385

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[4.7/4.8/4.9 Regression]    |[4.7 Regression] likely
                   |likely wrong code bug       |wrong code bug

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed for 4.8.2+ so far.

[Bug middle-end/58385] [4.7 Regression] likely wrong code bug

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58385

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to work|                            |4.8.2
         Resolution|---                         |FIXED
   Target Milestone|4.7.4                       |4.8.2
      Known to fail|                            |4.7.4

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed for 4.8.2.