[Bug tree-optimization/42154] New: [4.5 Regression] Wrong code from (early) SRA

[Bug tree-optimization/42154] New: [4.5 Regression] Wrong code from (early) SRA

[rguenth at gcc dot gnu dot org]

struct A { char x[1]; };
extern void abort (void);
void __attribute__((noinline,noclone))
foo (struct A a)
{
  if (a.x[0] != 'a')
    abort ();
}
int main ()
{
  struct A a;
  int i;
  for (i = 0; i < 1; ++i)
    a.x[i] = 'a';
  foo (a);
  return 0;
}

fails at -O1 because (early) SRA converts

<bb 2>:
  i_2 = 0;
  goto <bb 4>;

<bb 3>:
  a.x[i_1] = 97;
  i_3 = i_1 + 1;

<bb 4>:
  # i_1 = PHI <0(2), i_3(3)>
  if (i_1 <= 0)
    goto <bb 3>;
  else
    goto <bb 5>;

<bb 5>:
  foo (a);

to

<bb 2>:
  i_2 = 0;
  goto <bb 4>;

<bb 3>:
  a$x$_9 = 97;
  i_3 = i_1 + 1;

<bb 4>:
  # i_1 = PHI <0(2), i_3(3)>
  # a$x$_7 = PHI <a$x$_4(D)(2), a$x$_9(3)>
  if (i_1 <= 0)
    goto <bb 3>;
  else
    goto <bb 5>;

<bb 5>:
  a.x[i_1] = a$x$_7;
  foo (a);


see how the store to a.x[i_1] is wrong as i_1 does no longer have the same
value as before (SRA invalidly moved it out of the loop).  SRA should have
replaced i_1 with zero as it reasoned there is only one element and only
because of that it SRAd this.


-- 
           Summary: [4.5 Regression] Wrong code from (early) SRA
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42154

[Bug tree-optimization/42154] [4.5 Regression] Wrong code from (early) SRA

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42154

[Bug tree-optimization/42154] [4.5 Regression] Wrong code from (early) SRA

[jamborm at gcc dot gnu dot org]

------- Comment #1 from jamborm at gcc dot gnu dot org  2009-11-23 14:01 -------
I'm looking into this.  This example shows why using access->expr to create new
expressions is a dangerous thing to do, at least in some contexts (which I did
not really realize until now). I'd better look at them all.


-- 

jamborm at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jamborm at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-11-23 14:01:46
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42154

[Bug tree-optimization/42154] [4.5 Regression] Wrong code from (early) SRA

[jamborm at gcc dot gnu dot org]

------- Comment #2 from jamborm at gcc dot gnu dot org  2009-11-23 22:19 -------
Proposed patch:

http://gcc.gnu.org/ml/gcc-patches/2009-11/msg01311.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42154

[Bug tree-optimization/42154] [4.5 Regression] Wrong code from (early) SRA

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2009-11-24 09:55 -------
*** Bug 42160 has been marked as a duplicate of this bug. ***


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hp at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42154

[Bug tree-optimization/42154] [4.5 Regression] Wrong code from (early) SRA

[jamborm at gcc dot gnu dot org]

------- Comment #4 from jamborm at gcc dot gnu dot org  2009-11-24 10:56 -------
Subject: Bug 42154

Author: jamborm
Date: Tue Nov 24 10:56:14 2009
New Revision: 154493

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=154493
Log:
2009-11-24  Martin Jambor  <mjambor@suse.cz>

        PR tree-optimization/42154
        * tree-sra.c (struct access): Added comments.
        (sra_modify_expr): Build references to the old aggregate with
        build_ref_for_offset instead of reusing access->expr.
        (load_assign_lhs_subreplacements): Likewise.

        * testsuite/gcc.c-torture/execute/pr42154.c: New test.


Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/pr42154.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-sra.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42154

[Bug tree-optimization/42154] [4.5 Regression] Wrong code from (early) SRA

[jamborm at gcc dot gnu dot org]

------- Comment #5 from jamborm at gcc dot gnu dot org  2009-11-24 10:58 -------
Fixed.


-- 

jamborm at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42154

[Bug tree-optimization/42154] [4.5 Regression] Wrong code from (early) SRA

[hjl at gcc dot gnu dot org]

------- Comment #6 from hjl at gcc dot gnu dot org  2009-12-11 23:39 -------
Subject: Bug 42154

Author: hjl
Date: Fri Dec 11 23:36:24 2009
New Revision: 155184

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=155184
Log:
Backport testcases from trunk.

2009-12-11  H.J. Lu  <hongjiu.lu@intel.com>

        Backport from mainline:
        2009-12-11  Dodji Seketeli  <dodji@redhat.com>

        PR c++/42225
        * g++.dg/template/typedef24.C: New test.
        * g++.dg/template/typedef25.C: New test.

        2009-12-11  Dodji Seketeli  <dodji@redhat.com>

        PR c++/42251
        * g++.dg/template/const3.C: New test.

        2009-12-10  Jakub Jelinek  <jakub@redhat.com>

        PR c++/42317
        * g++.dg/opt/dtor2.C: New test.
        * g++.dg/opt/dtor2.h: New file.
        * g++.dg/opt/dtor2-aux.cc: New file.

        2009-12-10  Jan Hubicka  <jh@suse.cz>

        PR middle-end/42110
        * g++.dg/torture/pr42110.C: new file.

        2009-12-07  Jakub Jelinek  <jakub@redhat.com>

        PR debug/42244
        * gcc.dg/debug/pr42244.c: New test.

        2009-12-04  David Daney  <ddaney@caviumnetworks.com>

        PR rtl-optimization/42164
        * gcc.c-torture/compile/pr42164.c: New test.

        2009-12-03  Jason Merrill  <jason@redhat.com>

        PR c++/41611
        * g++.dg/abi/guard2.C: New.

        2009-12-03  Dodji Seketeli  <dodji@redhat.com>

        PR c++/42217
        * g++.dg/other/bitfield4.C: New test.

        2009-12-03  Jakub Jelinek  <jakub@redhat.com>

        PR c++/42256
        * g++.dg/inherit/thunk11.C: New test.
        * g++.dg/inherit/thunk11.h: New file.
        * g++.dg/inherit/thunk11-aux.cc: New file.

        2009-12-01  Martin Jambor  <mjambor@suse.cz>

        PR tree-optimization/42237
        * gcc.c-torture/compile/pr42237.c: New test.

        2009-12-01  Paolo Carlini  <paolo.carlini@oracle.com>

        PR c++/42057
        * g++.dg/parse/crash54.C: New.

        2009-11-30  Martin Jambor  <mjambor@suse.cz>

        PR middle-end/42196
        * gcc.c-torture/compile/pr42196-1.c: New test.
        * gcc.c-torture/compile/pr42196-2.c: New test.
        * gcc.c-torture/compile/pr42196-3.c: New test.

        2009-11-30  Dodji Seketeli  <dodji@redhat.com>

        PR c++/42069
        * g++.dg/template/typedef23.C: New test.

        2009-11-29  H.J. Lu  <hongjiu.lu@intel.com>

        PR tree-optimization/41961
        * g++.dg/tree-ssa/pr41961.C: New.

        2009-11-29  Ira Rosen  <irar@il.ibm.com>

        PR tree-optimization/42193
        * gcc.dg/vect/pr42193.c: New test.

        2009-11-28  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/42183
        * g++.dg/torture/pr42183.C: New testcase.

        2009-11-27  Martin Jambor  <mjambor@suse.cz>

        PR middle-end/42006
        * gcc.c-torture/execute/pr42006.c: New test.

        2009-11-27  Michael Matz  <matz@suse.de>

        PR rtl-optimization/42084
        * gcc.dg/pr42084.c: New test.

        2009-11-27  Michael Matz  <matz@suse.de>

        PR c++/41906
        * g++.dg/tree-ssa/pr41906.C: New testcase.

        2009-11-26  Michael Matz  <matz@suse.de>

        PR tree-optimization/41905
        * g++.dg/tree-ssa/pr41905.C: New testcase.

        2009-11-24  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/42142
        * gcc.c-torture/execute/pr42142.c: New testcase.

        2009-11-24  Martin Jambor  <mjambor@suse.cz>

        PR tree-optimization/42154
        * gcc.c-torture/execute/pr42154.c: New test.

        2009-11-21  Martin Jambor  <mjambor@suse.cz>

        PR middle-end/42025
        * gcc.c-torture/compile/pr42025-1.c: New test.
        * gcc.c-torture/compile/pr42025-2.c: New test.

        2009-11-21  Jakub Jelinek  <jakub@redhat.com>

        PR tree-optimization/42078
        * gcc.dg/pr42078.c: New test.

Added:
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/abi/guard2.C
      - copied unchanged from r155170, trunk/gcc/testsuite/g++.dg/abi/guard2.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/inherit/thunk11-aux.cc
      - copied unchanged from r155170,
trunk/gcc/testsuite/g++.dg/inherit/thunk11-aux.cc
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/inherit/thunk11.C
      - copied unchanged from r155170,
trunk/gcc/testsuite/g++.dg/inherit/thunk11.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/inherit/thunk11.h
      - copied unchanged from r155170,
trunk/gcc/testsuite/g++.dg/inherit/thunk11.h
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/opt/dtor2-aux.cc
      - copied unchanged from r155170,
trunk/gcc/testsuite/g++.dg/opt/dtor2-aux.cc
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/opt/dtor2.C
      - copied unchanged from r155170, trunk/gcc/testsuite/g++.dg/opt/dtor2.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/opt/dtor2.h
      - copied unchanged from r155170, trunk/gcc/testsuite/g++.dg/opt/dtor2.h
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/other/bitfield4.C
      - copied unchanged from r155170,
trunk/gcc/testsuite/g++.dg/other/bitfield4.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/parse/crash54.C
      - copied unchanged from r155172,
trunk/gcc/testsuite/g++.dg/parse/crash54.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/template/const3.C
      - copied unchanged from r155170,
trunk/gcc/testsuite/g++.dg/template/const3.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/template/typedef23.C
      - copied unchanged from r155181,
trunk/gcc/testsuite/g++.dg/template/typedef23.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/template/typedef24.C
      - copied unchanged from r155170,
trunk/gcc/testsuite/g++.dg/template/typedef24.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/template/typedef25.C
      - copied unchanged from r155170,
trunk/gcc/testsuite/g++.dg/template/typedef25.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/torture/pr42110.C
      - copied unchanged from r155170,
trunk/gcc/testsuite/g++.dg/torture/pr42110.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/torture/pr42183.C
      - copied unchanged from r155181,
trunk/gcc/testsuite/g++.dg/torture/pr42183.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/tree-ssa/pr41905.C
      - copied unchanged from r155182,
trunk/gcc/testsuite/g++.dg/tree-ssa/pr41905.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/tree-ssa/pr41906.C
      - copied unchanged from r155182,
trunk/gcc/testsuite/g++.dg/tree-ssa/pr41906.C
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/tree-ssa/pr41961.C
      - copied unchanged from r155181,
trunk/gcc/testsuite/g++.dg/tree-ssa/pr41961.C
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/compile/pr42025-1.c
      - copied unchanged from r155182,
trunk/gcc/testsuite/gcc.c-torture/compile/pr42025-1.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/compile/pr42025-2.c
      - copied unchanged from r155182,
trunk/gcc/testsuite/gcc.c-torture/compile/pr42025-2.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/compile/pr42164.c
      - copied unchanged from r155170,
trunk/gcc/testsuite/gcc.c-torture/compile/pr42164.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/compile/pr42196-1.c
      - copied unchanged from r155181,
trunk/gcc/testsuite/gcc.c-torture/compile/pr42196-1.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/compile/pr42196-2.c
      - copied unchanged from r155181,
trunk/gcc/testsuite/gcc.c-torture/compile/pr42196-2.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/compile/pr42196-3.c
      - copied unchanged from r155181,
trunk/gcc/testsuite/gcc.c-torture/compile/pr42196-3.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/compile/pr42237.c
      - copied unchanged from r155171,
trunk/gcc/testsuite/gcc.c-torture/compile/pr42237.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/execute/pr42006.c
      - copied unchanged from r155181,
trunk/gcc/testsuite/gcc.c-torture/execute/pr42006.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/execute/pr42142.c
      - copied unchanged from r155182,
trunk/gcc/testsuite/gcc.c-torture/execute/pr42142.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/execute/pr42154.c
      - copied unchanged from r155182,
trunk/gcc/testsuite/gcc.c-torture/execute/pr42154.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.dg/debug/pr42244.c
      - copied unchanged from r155170,
trunk/gcc/testsuite/gcc.dg/debug/pr42244.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.dg/pr42078.c
      - copied unchanged from r155182, trunk/gcc/testsuite/gcc.dg/pr42078.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.dg/pr42084.c
      - copied unchanged from r155182, trunk/gcc/testsuite/gcc.dg/pr42084.c
    branches/gcc-4_4-branch/gcc/testsuite/gcc.dg/vect/pr42193.c
      - copied unchanged from r155181,
trunk/gcc/testsuite/gcc.dg/vect/pr42193.c
Modified:
    branches/gcc-4_4-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42154