[Bug tree-optimization/64807] New: [5 Regression] Wrong-code because of wide-int division

[Bug tree-optimization/64807] New: [5 Regression] Wrong-code because of wide-int division

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64807

            Bug ID: 64807
           Summary: [5 Regression] Wrong-code because of wide-int division
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
                CC: emsr at gcc dot gnu.org, jakub at gcc dot gnu.org,
                    nheghathivhistha at gmail dot com, segher at gcc dot gnu.org,
                    trippels at gcc dot gnu.org
        Depends on: 63504, 63988

/* { dg-do run { target int128 } } */
/* { dg-options "-O2" } */

__uint128_t
foo (void)
{
  __uint128_t a = -1;
  __uint128_t b = -1;
  return a / b;
}

int
main ()
{
  if (foo () != 1)
    __builtin_abort ();
  return 0;
}

is miscompiled starting with wide-int merge r210113.

[Bug tree-optimization/64807] [5 Regression] Wrong-code because of wide-int division

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64807

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2015-01-26
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 34582
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34582&action=edit
gcc5-pr64807.patch

Untested fix.

[Bug tree-optimization/64807] [5 Regression] Wrong-code because of wide-int division

[zadeck at naturalbridge dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64807

Kenneth Zadeck <zadeck at naturalbridge dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |zadeck at naturalbridge dot com

--- Comment #2 from Kenneth Zadeck <zadeck at naturalbridge dot com> ---
(In reply to Jakub Jelinek from comment #1)
> Created attachment 34582 [details]
> gcc5-pr64807.patch
> 
> Untested fix.

This looks ok to me.

[Bug tree-optimization/64807] [5 Regression] Wrong-code because of wide-int division

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64807

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Tue Jan 27 08:26:13 2015
New Revision: 220153

URL: https://gcc.gnu.org/viewcvs?rev=220153&root=gcc&view=rev
Log:
    PR tree-optimization/64807
    * wide-int.cc (wi::divmod_internal): Clear
    b_dividend[dividend_blocks_needed].

    * gcc.dg/pr64807.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/pr64807.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/wide-int.cc

[Bug tree-optimization/64807] [5 Regression] Wrong-code because of wide-int division

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64807

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |5.0

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.

[Bug tree-optimization/64807] [5 Regression] Wrong-code because of wide-int division

[LpSolit at netscape dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64807

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |5.0

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.

[Bug tree-optimization/64807] [5 Regression] Wrong-code because of wide-int division

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64807
Bug 64807 depends on bug 63504, which changed state.

Bug 63504 Summary: [5 Regression] Issues found by --enable-checking=valgrind
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63504

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

[Bug tree-optimization/64807] [5 Regression] Wrong-code because of wide-int division

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64807
Bug 64807 depends on bug 63988, which changed state.

Bug 63988 Summary: heap-buffer-overflow in combine.c on ppc64
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63988

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