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* [Bug tree-optimization/65216] New: wrong code at -O3 on x86_64-linux-gnu
@ 2015-02-26  1:19 su at cs dot ucdavis.edu
  2015-02-26  3:15 ` [Bug tree-optimization/65216] " ktietz at gcc dot gnu.org
                   ` (8 more replies)
  0 siblings, 9 replies; 10+ messages in thread
From: su at cs dot ucdavis.edu @ 2015-02-26  1:19 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65216

            Bug ID: 65216
           Summary: wrong code at -O3 on x86_64-linux-gnu
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu

The current gcc trunk miscompiles the following code on x86_64-linux at -O3 in
both 32-bit and 64-bit modes. 

This is a regression from 4.9.x. 

$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-unknown-linux-gnu/5.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-trunk/configure --prefix=/usr/local/gcc-trunk
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 5.0.0 20150225 (experimental) [trunk revision 220958] (GCC) 
$ 
$ gcc-trunk -O2 small.c; a.out
$ gcc-4.9 -O3 small.c; a.out
$ 
$ gcc-trunk -O3 small.c
$ ./a.out
Aborted (core dumped)
$ 


--------------------------------------


int a, b = 62, e;
volatile int c;
volatile int d;

int
main ()
{
  int f = a = 0;
  for (; a < 2; a++)
    {
      b &= (8 ^ f) & 1;
      for (e = 0; e < 6; e++)
    if (c)
      f = d;
    }

  if (b != 0) 
    __builtin_abort (); 

  return 0;
}


^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2015-03-04 12:30 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-02-26  1:19 [Bug tree-optimization/65216] New: wrong code at -O3 on x86_64-linux-gnu su at cs dot ucdavis.edu
2015-02-26  3:15 ` [Bug tree-optimization/65216] " ktietz at gcc dot gnu.org
2015-02-26  3:45 ` glisse at gcc dot gnu.org
2015-02-26  5:26 ` [Bug tree-optimization/65216] [5 Regression] " ktietz at gcc dot gnu.org
2015-02-26  8:39 ` jakub at gcc dot gnu.org
2015-02-26 10:14 ` rguenth at gcc dot gnu.org
2015-02-26 12:49 ` jakub at gcc dot gnu.org
2015-02-27  0:12 ` jakub at gcc dot gnu.org
2015-02-27  0:25 ` jakub at gcc dot gnu.org
2015-03-04 12:30 ` ktietz at gcc dot gnu.org

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