[Bug tree-optimization/54494] New: Missing store to volatile

[Bug tree-optimization/54494] New: Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

             Bug #: 54494
           Summary: Missing store to volatile
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: pinskia@gcc.gnu.org


Consider:

extern const unsigned long base;
static inline void wreg(unsigned char val, unsigned long addr)
{
   *((volatile unsigned char *) (base + addr)) = val;
}
void wreg_twice(void)
{
   wreg(0, 42);
   wreg(0, 42);
}
---- CUT ---
At -O2 the second store to the volatile char is removed by the strlen pass.

[Bug tree-optimization/54494] [4.7/4.8 Regression] Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
         AssignedTo|unassigned at gcc dot       |pinskia at gcc dot gnu.org
                   |gnu.org                     |
   Target Milestone|---                         |4.7.2
            Summary|Missing store to volatile   |[4.7/4.8 Regression]
                   |                            |Missing store to volatile

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-05 17:48:42 UTC ---
I am going to fix this.
Note this is causing the mips linux kernel to become unstable.

[Bug tree-optimization/54494] [4.7/4.8 Regression] Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2012-09-05
      Known to work|                            |4.6.1
     Ever Confirmed|0                           |1
      Known to fail|                            |4.7.0, 4.7.1, 4.8.0

[Bug tree-optimization/54494] [4.7/4.8 Regression] Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-05 18:23:56 UTC ---
Created attachment 28134
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28134
Patch which fixes the problem

Here is the fix.

[Bug tree-optimization/54494] [4.7/4.8 Regression] Missing store to volatile

[ralf@linux-mips.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

Ralf Baechle <ralf@linux-mips.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ralf@linux-mips.org

--- Comment #3 from Ralf Baechle <ralf@linux-mips.org> 2012-09-05 20:06:47 UTC ---
I've tested your proposed fix with the kernel configuration that I extracted
the test case from and I'm happy to report that the patch is working for me.

[Bug tree-optimization/54494] [4.7/4.8 Regression] Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|http://gcc.gnu.org/ml/gcc-p |http://gcc.gnu.org/ml/gcc-p
                   |atches/2012-09/msg00321.htm |atches/2012-09/msg00350.htm
                   |l                           |l

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-06 04:12:03 UTC ---
Updated patch:
http://gcc.gnu.org/ml/gcc-patches/2012-09/msg00350.html

[Bug tree-optimization/54494] [4.7/4.8 Regression] Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-06 08:08:21 UTC ---
Author: pinskia
Date: Thu Sep  6 08:08:09 2012
New Revision: 191014

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=191014
Log:
2012-09-06  Andrew Pinski  <apinski@cavium.com>

        PR tree-opt/54494
        * tree-inline.c (remap_gimple_op_r): Copy TREE_SIDE_EFFECTS also.
2012-09-06  Andrew Pinski  <apinski@cavium.com>

        PR tree-opt/54494
        * gcc.dg/tree-ssa/strlen-1.c: New testcase.


Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/strlen-1.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-inline.c

[Bug tree-optimization/54494] [4.7 Regression] Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.8.0
            Summary|[4.7/4.8 Regression]        |[4.7 Regression] Missing
                   |Missing store to volatile   |store to volatile
      Known to fail|4.8.0                       |

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-06 08:08:21 UTC ---
Author: pinskia
Date: Thu Sep  6 08:08:09 2012
New Revision: 191014

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=191014
Log:
2012-09-06  Andrew Pinski  <apinski@cavium.com>

        PR tree-opt/54494
        * tree-inline.c (remap_gimple_op_r): Copy TREE_SIDE_EFFECTS also.
2012-09-06  Andrew Pinski  <apinski@cavium.com>

        PR tree-opt/54494
        * gcc.dg/tree-ssa/strlen-1.c: New testcase.


Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/strlen-1.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-inline.c

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-06 08:09:13 UTC ---
Fixed on the trunk so far.

[Bug tree-optimization/54494] [4.7 Regression] Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.8.0
            Summary|[4.7/4.8 Regression]        |[4.7 Regression] Missing
                   |Missing store to volatile   |store to volatile
      Known to fail|4.8.0                       |

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-06 08:09:13 UTC ---
Fixed on the trunk so far.

[Bug tree-optimization/54494] [4.7 Regression] Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-06 13:51:45 UTC ---
Author: pinskia
Date: Thu Sep  6 13:51:37 2012
New Revision: 191025

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=191025
Log:
2012-09-06  Andrew Pinski  <apinski@cavium.com>

        PR tree-opt/54494
        * tree-inline.c (remap_gimple_op_r): Copy TREE_SIDE_EFFECTS also.
2012-09-06  Andrew Pinski  <apinski@cavium.com>

        PR tree-opt/54494
        * gcc.dg/tree-ssa/strlen-1.c: New testcase.


Added:
    branches/gcc-4_7-branch/gcc/testsuite/gcc.dg/tree-ssa/strlen-1.c
      - copied unchanged from r191014,
trunk/gcc/testsuite/gcc.dg/tree-ssa/strlen-1.c
Modified:
    branches/gcc-4_7-branch/   (props changed)
    branches/gcc-4_7-branch/gcc/ChangeLog
    branches/gcc-4_7-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_7-branch/gcc/tree-inline.c

Propchange: branches/gcc-4_7-branch/
            ('svn:mergeinfo' modified)

[Bug tree-optimization/54494] [4.7 Regression] Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

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

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

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-06 13:53:57 UTC ---
Fixed.

--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-06 13:53:57 UTC ---
Fixed.

[Bug tree-optimization/54494] [4.7 Regression] Missing store to volatile

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494

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

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

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-06 13:53:57 UTC ---
Fixed.

--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-06 13:53:57 UTC ---
Fixed.