[Bug middle-end/34768] New: [4.1/4.2/4.3 Regression] Wrong code with conditional function invocation

[Bug middle-end/34768] New: [4.1/4.2/4.3 Regression] Wrong code with conditional function invocation

[rguenth at gcc dot gnu dot org]

int x;

void __attribute__((noinline)) foo (void)
{
  x = -x;
}
void __attribute__((const,noinline)) bar (void)
{
}

int __attribute__((noinline))
test (int c)
{
  int tmp = x;
  (c ? foo : bar) ();
  return tmp + x;
}

extern void abort (void);
int main()
{
  x = 1;
  if (test (1) != 0)
    abort ();
  return 0;
}

creates wrong code because the side-effect of the call to foo() is not
accounted for.

Since the merge of tree-ssa already gimplification removes the function call.
Thus, the above fails with -O0.


If you modify the testcase to use the return-value, you see that wrong
alias information is created because we appearantly use the const attribute
for the indirect call.

int x;

int __attribute__((noinline)) foo (void)
{
  x = -x;
  return 0;
}
int __attribute__((const,noinline)) bar (void)
{
  return 0;
}

int __attribute__((noinline))
test (int c)
{
  int tmp = x;
  int res = (c ? foo : bar) ();
  return tmp + x + res;
}

extern void abort (void);
int main()
{
  x = 1;
  if (test (1) != 0)
    abort ();
  return 0;
}

alias produced is:

test (c)
{
  int res;
  int tmp;
  int D.1207;
  int x.3;
  int D.1205;
  int (*<T240>) (void) iftmp.2;

<bb 2>:
  # VUSE <x_11(D)>
  tmp_2 = x;
  if (c_3(D) != 0)
    goto <bb 4>;
  else
    goto <bb 3>;

<bb 3>:

<bb 4>:
  # iftmp.2_1 = PHI <foo(2), bar(3)>
  res_6 = iftmp.2_1 ();
  # VUSE <x_11(D)>
  x.3_7 = x;
  D.1207_8 = tmp_2 + x.3_7;
  D.1205_9 = D.1207_8 + res_6;
  return D.1205_9;

}

and we happily CSE the load from x.  This testcase requires -O to fail.


-- 
           Summary: [4.1/4.2/4.3 Regression] Wrong code with conditional
                    function invocation
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: middle-end
        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=34768

[Bug middle-end/34768] [4.1/4.2/4.3 Regression] Wrong code with conditional function invocation

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2008-01-13 13:23 -------
Mine.  Probably also causes PR32139.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
OtherBugsDependingO|                            |32139
              nThis|                            |
         AssignedTo|unassigned at gcc dot gnu   |rguenth at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
      Known to fail|                            |4.0.4 4.1.3 4.2.3 4.3.0
      Known to work|                            |3.4.6
           Priority|P3                          |P1
   Last reconfirmed|0000-00-00 00:00:00         |2008-01-13 13:23:55
               date|                            |
   Target Milestone|---                         |4.1.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34768

[Bug c/34768] [4.1/4.2/4.3 Regression] Wrong code with conditional function invocation

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2008-01-13 13:25 -------
Um, this is a FE bug.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |c


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34768

[Bug c/34768] [4.1/4.2/4.3 Regression] Wrong code with conditional function invocation

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2008-01-13 13:50 -------
The bug is in common_pointer_type (), where we merge the function type
qualifiers (TYPE_READONLY is used for 'const' functions):

  else if (TYPE_P (exp) && TYPE_READONLY (exp) && ! TREE_THIS_VOLATILE (exp))
    flags |= ECF_CONST;

volatile is used as 'noreturn'.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34768

[Bug c/34768] [4.1/4.2/4.3 Regression] Wrong code with conditional function invocation

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2008-01-13 17:49 -------
THis is related to PR 29382 and PR 13519.  And I think this is exactly the same
issue as PR 28289.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34768

[Bug c/34768] [4.1/4.2/4.3 Regression] Wrong code with conditional function invocation

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2008-01-13 18:17 -------
*** Bug 28289 has been marked as a duplicate of this bug. ***


-- 

rguenth at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34768

[Bug c/34768] [4.1/4.2/4.3 Regression] Wrong code with conditional function invocation

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2008-01-16 09:45 -------
Subject: Bug 34768

Author: rguenth
Date: Wed Jan 16 09:44:23 2008
New Revision: 131568

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=131568
Log:
2008-01-16  Richard Guenther  <rguenther@suse.de>

        PR c/34768
        * c-typeck.c (common_pointer_type): Do not merge inconsistent
        type qualifiers for function types.

        * gcc.c-torture/execute/pr34768-1.c: New testcase.
        * gcc.c-torture/execute/pr34768-2.c: Likewise.

Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/pr34768-1.c
    trunk/gcc/testsuite/gcc.c-torture/execute/pr34768-2.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/c-typeck.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34768

[Bug c/34768] [4.1/4.2 Regression] Wrong code with conditional function invocation

[rguenth at gcc dot gnu dot org]

------- Comment #7 from rguenth at gcc dot gnu dot org  2008-01-16 09:47 -------
Fixed on the trunk.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|3.4.6                       |3.4.6 4.3.0
            Summary|[4.1/4.2/4.3 Regression]    |[4.1/4.2 Regression] Wrong
                   |Wrong code with conditional |code with conditional
                   |function invocation         |function invocation


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34768

[Bug c/34768] [4.1/4.2 Regression] Wrong code with conditional function invocation

[rguenth at gcc dot gnu dot org]

------- Comment #8 from rguenth at gcc dot gnu dot org  2008-01-22 14:46 -------
Subject: Bug 34768

Author: rguenth
Date: Tue Jan 22 14:45:56 2008
New Revision: 131723

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=131723
Log:
2008-01-22  Richard Guenther  <rguenther@suse.de>

        PR middle-end/34739
        Backport from mainline
        2008-01-16  Richard Guenther  <rguenther@suse.de>

        PR c/34768
        * c-typeck.c (common_pointer_type): Do not merge inconsistent
        type qualifiers for function types.

        2007-11-12  Richard Guenther  <rguenther@suse.de>

        PR middle-end/34070
        * fold-const.c (fold_binary): If testing for non-negative
        operands with tree_expr_nonnegative_warnv_p make sure to
        use op0 which has all (sign) conversions retained.

        2006-10-24  Richard Guenther  <rguenther@suse.de>

        PR middle-end/28796
        * builtins.c (fold_builtin_classify): Use HONOR_INFINITIES
        and HONOR_NANS instead of MODE_HAS_INFINITIES and MODE_HAS_NANS
        for deciding optimizations in consistency with fold-const.c
        (fold_builtin_unordered_cmp): Likewise.

Added:
    branches/gcc-4_2-branch/gcc/testsuite/gcc.c-torture/execute/pr34070-1.c
      - copied unchanged from r130098,
trunk/gcc/testsuite/gcc.c-torture/execute/pr34070-1.c
    branches/gcc-4_2-branch/gcc/testsuite/gcc.c-torture/execute/pr34070-2.c
      - copied unchanged from r130098,
trunk/gcc/testsuite/gcc.c-torture/execute/pr34070-2.c
    branches/gcc-4_2-branch/gcc/testsuite/gcc.c-torture/execute/pr34768-1.c
      - copied unchanged from r131568,
trunk/gcc/testsuite/gcc.c-torture/execute/pr34768-1.c
    branches/gcc-4_2-branch/gcc/testsuite/gcc.c-torture/execute/pr34768-2.c
      - copied unchanged from r131568,
trunk/gcc/testsuite/gcc.c-torture/execute/pr34768-2.c
    branches/gcc-4_2-branch/gcc/testsuite/gcc.dg/pr28796-1.c
      - copied unchanged from r118001, trunk/gcc/testsuite/gcc.dg/pr28796-1.c
    branches/gcc-4_2-branch/gcc/testsuite/gcc.dg/pr28796-2.c
      - copied unchanged from r118001, trunk/gcc/testsuite/gcc.dg/pr28796-2.c
Modified:
    branches/gcc-4_2-branch/gcc/ChangeLog
    branches/gcc-4_2-branch/gcc/builtins.c
    branches/gcc-4_2-branch/gcc/c-typeck.c
    branches/gcc-4_2-branch/gcc/fold-const.c
    branches/gcc-4_2-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34768

[Bug c/34768] [4.1 Regression] Wrong code with conditional function invocation

[rguenth at gcc dot gnu dot org]

------- Comment #9 from rguenth at gcc dot gnu dot org  2008-01-22 14:51 -------
Fixed on the 4.2 branch.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|rguenth at gcc dot gnu dot  |unassigned at gcc dot gnu
                   |org                         |dot org
             Status|ASSIGNED                    |NEW
      Known to fail|4.0.4 4.1.3 4.2.3 4.3.0     |4.0.4 4.1.3
      Known to work|3.4.6 4.3.0                 |3.4.6 4.2.3 4.3.0
            Summary|[4.1/4.2 Regression] Wrong  |[4.1 Regression] Wrong code
                   |code with conditional       |with conditional function
                   |function invocation         |invocation


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34768

[Bug c/34768] [4.1 Regression] Wrong code with conditional function invocation

[jsm28 at gcc dot gnu dot org]

------- Comment #10 from jsm28 at gcc dot gnu dot org  2008-07-04 16:17 -------
Closing 4.1 branch.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|4.1.3                       |4.2.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34768