[Bug tree-optimization/39074] New: PTA constraint processing for *x = y is wrong

[Bug tree-optimization/39074] New: PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

if the solution of x includes ANYTHING we fail to add the solution of y to all
variables.  Testcase (fails on a-i branch):

int i;
void __attribute__((noinline))
foo(long b, long q)
{
  int *y;
  int **a = &y, **x;
  int ***p;
  if (b)
    p = (int ***)q;
  else
    p = &a;
  x = *p;
  *x = &i;
  *y = 0;
}
extern void abort (void);
int main()
{
  i = 1;
  foo (0, 0);
  if (i != 0)
    abort ();
  return 0;
}

I guess we should warn for dereferenced pointers whos points-to set is empty
with "warning: dereferencing uninitialized pointer".


-- 
           Summary: PTA constraint processing for *x = y is wrong
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: wrong-code, alias
          Severity: major
          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=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2009-02-02 14:03 -------
We could for example warn for

/* { dg-do compile } */
/* { dg-options "-O -Wuninitialized" } */

int i;
int __attribute((const,noinline))
foo (int **p)
{
  return i;
}
int bar(int *q)
{
  int *p;
  *q = 0;
  int j = foo(&p);
  return *p + j;  /* { dg-warning "dereferencing uninitialized" } */
}


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |rguenth at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-02-02 14:03:04
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2009-02-02 14:07 -------
Created an attachment (id=17227)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17227&action=view)
patch to warn about uninitialized pointer dereferences

This patch causes a warning for both testcases, the program and the PTA bug.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[dberlin at gcc dot gnu dot org]

------- Comment #3 from dberlin at gcc dot gnu dot org  2009-02-02 19:42 -------
Eyeballing this, I think y should not end up empty anyway.

Shouldn't it have i in it's points-to set?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2009-02-03 09:17 -------
Yes, but as the store to y is via *x and x points to { ANYTHING } (via the
non-pointer (int ***)q) only (as x already includes ANYTHING we do not add
a for the second constraint), so for *x = &i we fail to add a to y.

For reference, here are the constraints:

a = &y
p_4 = &ANYTHING
p_1 = p_4
p_1 = &a
x_6 = *p_1
derefaddrtmp.9 = &i
*x_6 = derefaddrtmp.9
y.0_7 = y

and the solutions:

a = { y }
y = same as y.0_7
p_4 = { ANYTHING }
p_1 = { ANYTHING a }
x_6 = { ANYTHING }
i = { }
derefaddrtmp.9 = { i }
y.0_7 = { }

while correct would be if everything would point to at least i (through
the effective *ANYTHING = &i constraint)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[dberlin at dberlin dot org]

------- Comment #5 from dberlin at gcc dot gnu dot org  2009-02-03 14:16 -------
Subject: Re:  PTA constraint processing for *x = 
        y is wrong

There used to be a *ANYTHING = ANYTHING constraint + ANYTHING
containing all the variables pointing to ANYTHING that would have
taken care of this.
You certainly don't want to dynamically add all variables at solving
time yourself, since that can't be optimized.

On Tue, Feb 3, 2009 at 4:17 AM, rguenth at gcc dot gnu dot org
<gcc-bugzilla@gcc.gnu.org> wrote:
>
>
> ------- Comment #4 from rguenth at gcc dot gnu dot org  2009-02-03 09:17 -------
> Yes, but as the store to y is via *x and x points to { ANYTHING } (via the
> non-pointer (int ***)q) only (as x already includes ANYTHING we do not add
> a for the second constraint), so for *x = &i we fail to add a to y.
>
> For reference, here are the constraints:
>
> a = &y
> p_4 = &ANYTHING
> p_1 = p_4
> p_1 = &a
> x_6 = *p_1
> derefaddrtmp.9 = &i
> *x_6 = derefaddrtmp.9
> y.0_7 = y
>
> and the solutions:
>
> a = { y }
> y = same as y.0_7
> p_4 = { ANYTHING }
> p_1 = { ANYTHING a }
> x_6 = { ANYTHING }
> i = { }
> derefaddrtmp.9 = { i }
> y.0_7 = { }
>
> while correct would be if everything would point to at least i (through
> the effective *ANYTHING = &i constraint)
>
>
> --
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074
>
> ------- You are receiving this mail because: -------
> You are on the CC list for the bug, or are watching someone who is.
>


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[rguenther at suse dot de]

------- Comment #6 from rguenther at suse dot de  2009-02-03 14:24 -------
Subject: Re:  PTA constraint processing for *x
 = y is wrong

On Tue, 3 Feb 2009, dberlin at dberlin dot org wrote:

> Subject: Re:  PTA constraint processing for *x = 
>         y is wrong
> 
> There used to be a *ANYTHING = ANYTHING constraint + ANYTHING
> containing all the variables pointing to ANYTHING that would have
> taken care of this.
> You certainly don't want to dynamically add all variables at solving
> time yourself, since that can't be optimized.

This is the reason it "works" for ESCAPED, there we have an
*ESCAPED = ESCAPED constraint.  It doesn't work for CALLUSED though,
I have a simple fix (CALLUSED is not big usually, so just not using
it as a placeholder fixes the issue here).

For the ANYTHING problem I have just dealt with it in do_ds_constraint
(I'll post an updated patch soon after testing finished).

Richard.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[dberlin at dberlin dot org]

------- Comment #7 from dberlin at gcc dot gnu dot org  2009-02-04 00:29 -------
Subject: Re:  PTA constraint processing for *x = 
        y is wrong

On Tue, Feb 3, 2009 at 9:24 AM, rguenther at suse dot de
<gcc-bugzilla@gcc.gnu.org> wrote:
>
>
> ------- Comment #6 from rguenther at suse dot de  2009-02-03 14:24 -------
> Subject: Re:  PTA constraint processing for *x
>  = y is wrong
>
> On Tue, 3 Feb 2009, dberlin at dberlin dot org wrote:
>
>> Subject: Re:  PTA constraint processing for *x =
>>         y is wrong
>>
>> There used to be a *ANYTHING = ANYTHING constraint + ANYTHING
>> containing all the variables pointing to ANYTHING that would have
>> taken care of this.
>> You certainly don't want to dynamically add all variables at solving
>> time yourself, since that can't be optimized.
>
> This is the reason it "works" for ESCAPED, there we have an
> *ESCAPED = ESCAPED constraint.  It doesn't work for CALLUSED though,
> I have a simple fix (CALLUSED is not big usually, so just not using
> it as a placeholder fixes the issue here).
>
> For the ANYTHING problem I have just dealt with it in do_ds_constraint
> (I'll post an updated patch soon after testing finished).

My onl concern is practicality.
The last time I did this solely at solving time it was ridiculously
slow on large cases, since the solver is much better at difference
propagation.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[rguenther at suse dot de]

------- Comment #8 from rguenther at suse dot de  2009-02-04 09:35 -------
Subject: Re:  PTA constraint processing for *x
 = y is wrong

On Wed, 4 Feb 2009, dberlin at dberlin dot org wrote:

> ------- Comment #7 from dberlin at gcc dot gnu dot org  2009-02-04 00:29 -------
> Subject: Re:  PTA constraint processing for *x = 
>         y is wrong
> 
> On Tue, Feb 3, 2009 at 9:24 AM, rguenther at suse dot de
> <gcc-bugzilla@gcc.gnu.org> wrote:
> >
> >
> > ------- Comment #6 from rguenther at suse dot de  2009-02-03 14:24 -------
> > Subject: Re:  PTA constraint processing for *x
> >  = y is wrong
> >
> > On Tue, 3 Feb 2009, dberlin at dberlin dot org wrote:
> >
> >> Subject: Re:  PTA constraint processing for *x =
> >>         y is wrong
> >>
> >> There used to be a *ANYTHING = ANYTHING constraint + ANYTHING
> >> containing all the variables pointing to ANYTHING that would have
> >> taken care of this.
> >> You certainly don't want to dynamically add all variables at solving
> >> time yourself, since that can't be optimized.
> >
> > This is the reason it "works" for ESCAPED, there we have an
> > *ESCAPED = ESCAPED constraint.  It doesn't work for CALLUSED though,
> > I have a simple fix (CALLUSED is not big usually, so just not using
> > it as a placeholder fixes the issue here).
> >
> > For the ANYTHING problem I have just dealt with it in do_ds_constraint
> > (I'll post an updated patch soon after testing finished).
> 
> My onl concern is practicality.
> The last time I did this solely at solving time it was ridiculously
> slow on large cases, since the solver is much better at difference
> propagation.

Do you remember what testcase(s) this was?  I can certainly time
removing the shortcutting against handling *ANYTHING (and I'll try
to come up with a testcase that is not fixed with just removing
the shortcutting).

Richard.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #9 from rguenth at gcc dot gnu dot org  2009-02-04 12:16 -------
Testcase that is not fixed with removing the short-cutting:

int i;
long __attribute__((noinline,const)) bar(int ***p) { return (long)p; }
void __attribute__((noinline))
foo(void)
{
  int *y;
  int **a = &y, **x;
  int ***p;
  long b;
  b = bar(&a);
  p = (int ***)b;
  x = *p;
  *x = &i;
  *y = 0;
}
extern void abort (void);
int main()
{
  i = 1;
  foo ();
  if (i != 0)
    abort ();
  return 0;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #10 from rguenth at gcc dot gnu dot org  2009-02-04 12:26 -------
This one fails on trunk (where we fall back to anything for empty points-to
sets, so just add some unrelated &j and the vops are wrong):

int i;
long __attribute__((noinline,const)) bar(int ***p) { return (long)p; }
void __attribute__((noinline))
foo(void)
{
  int j;
  int *y = &j;
  int **a = &y, **x;
  int ***p;
  long b;
  b = bar(&a);
  p = (int ***)b;
  x = *p;
  *x = &i;
  *y = 0;
}
extern void abort (void);
int main()
{
  i = 1;
  foo ();
  if (i != 0)
    abort ();
  return 0;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #11 from rguenth at gcc dot gnu dot org  2009-02-04 12:31 -------
This one fails also on the branches that have PTA.

int i;
long __attribute__((noinline,const)) bar(int ***p) { return (long)p; }
extern void abort (void);
int main()
{
  int j;
  int *y = &j;
  int **a = &y, **x;
  int ***p;
  long b;
  b = bar(&a);
  p = (int ***)b;
  x = *p;
  *x = &i;
  i = 1;
  *y = 0;
  if (i != 0)
    abort ();
  return 0;
}


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |4.1.3 4.2.4 4.3.3 4.4.0
      Known to work|                            |4.0.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] [4.2/4.3/4.4 Regression] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #12 from rguenth at gcc dot gnu dot org  2009-02-04 12:37 -------
Which makes it a regression.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|PTA constraint processing   |[4.2/4.3/4.4 Regression] PTA
                   |for *x = y is wrong         |constraint processing for *x
                   |                            |= y is wrong
   Target Milestone|---                         |4.2.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] [4.2/4.3/4.4 Regression] PTA constraint processing for *x = y is wrong

[dberlin at dberlin dot org]

------- Comment #13 from dberlin at gcc dot gnu dot org  2009-02-04 16:09 -------
Subject: Re:  PTA constraint processing for *x = 
        y is wrong

I don't remember offhand.  At one point during 4.2 we used to compute
the anything set exactly, and it led to massive issues. Of course,
most of those were because the anything set had hundreds or thousands
of SFT's :).

I'm happy to go with your idea for fixing since fixing shortcutting
won't fix it, except for two things:
1. ANYTHING is really limited to all addressable variables (IE address
taken and escaping), instead of all variables.  It was never meant to
represent "completely unknown" (IE user has set pointer to  (char *)
0xdeadbeef).
ISTM the set you union in should be based on CALLUSED and ESCAPED or
something thereof, or at least should be computable with constraints
during solving, and unioned in when it changes.

The way off the top of my head to do this is to simply stop using
&ANYTHING, and use ANYTHING directly, and then have ANYTHING =
CALLUSED and ANYTHING = ESCAPED.

Assuming you hate that idea for some reason
2. It's probably a lot faster to make a bitmap of these and update it,
then union in the bitmap, than to iterate over all varinfos all the
time.

ISTM you are trying to avoid doing #1 by adding all variables, even
though this is going to give you worse than necessary results.

Intel actually iterates points-to solving in order to compute the set
of nonlocal locations without explicitly adding the set everywhere.

See the description of nloc in section 4.1 of  "On the Importance of
Points=To Analysis and Other
Memory Disambiguation Methods For C Programs"

On Wed, Feb 4, 2009 at 4:35 AM, rguenther at suse dot de
<gcc-bugzilla@gcc.gnu.org> wrote:
>
>
> ------- Comment #8 from rguenther at suse dot de  2009-02-04 09:35 -------
> Subject: Re:  PTA constraint processing for *x
>  = y is wrong
>
> On Wed, 4 Feb 2009, dberlin at dberlin dot org wrote:
>
>> ------- Comment #7 from dberlin at gcc dot gnu dot org  2009-02-04 00:29 -------
>> Subject: Re:  PTA constraint processing for *x =
>>         y is wrong
>>
>> On Tue, Feb 3, 2009 at 9:24 AM, rguenther at suse dot de
>> <gcc-bugzilla@gcc.gnu.org> wrote:
>> >
>> >
>> > ------- Comment #6 from rguenther at suse dot de  2009-02-03 14:24 -------
>> > Subject: Re:  PTA constraint processing for *x
>> >  = y is wrong
>> >
>> > On Tue, 3 Feb 2009, dberlin at dberlin dot org wrote:
>> >
>> >> Subject: Re:  PTA constraint processing for *x =
>> >>         y is wrong
>> >>
>> >> There used to be a *ANYTHING = ANYTHING constraint + ANYTHING
>> >> containing all the variables pointing to ANYTHING that would have
>> >> taken care of this.
>> >> You certainly don't want to dynamically add all variables at solving
>> >> time yourself, since that can't be optimized.
>> >
>> > This is the reason it "works" for ESCAPED, there we have an
>> > *ESCAPED = ESCAPED constraint.  It doesn't work for CALLUSED though,
>> > I have a simple fix (CALLUSED is not big usually, so just not using
>> > it as a placeholder fixes the issue here).
>> >
>> > For the ANYTHING problem I have just dealt with it in do_ds_constraint
>> > (I'll post an updated patch soon after testing finished).
>>
>> My onl concern is practicality.
>> The last time I did this solely at solving time it was ridiculously
>> slow on large cases, since the solver is much better at difference
>> propagation.
>
> Do you remember what testcase(s) this was?  I can certainly time
> removing the shortcutting against handling *ANYTHING (and I'll try
> to come up with a testcase that is not fixed with just removing
> the shortcutting).
>
> Richard.
>
>
> --
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074
>
> ------- You are receiving this mail because: -------
> You are on the CC list for the bug, or are watching someone who is.
>


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] [4.2/4.3/4.4 Regression] PTA constraint processing for *x = y is wrong

[rguenther at suse dot de]

------- Comment #14 from rguenther at suse dot de  2009-02-04 16:26 -------
Subject: Re:  [4.2/4.3/4.4 Regression] PTA
 constraint processing for *x = y is wrong

On Wed, 4 Feb 2009, dberlin at dberlin dot org wrote:

> ------- Comment #13 from dberlin at gcc dot gnu dot org  2009-02-04 16:09 -------
> Subject: Re:  PTA constraint processing for *x = 
>         y is wrong
> 
> I don't remember offhand.  At one point during 4.2 we used to compute
> the anything set exactly, and it led to massive issues. Of course,
> most of those were because the anything set had hundreds or thousands
> of SFT's :).
> 
> I'm happy to go with your idea for fixing since fixing shortcutting
> won't fix it, except for two things:
> 1. ANYTHING is really limited to all addressable variables (IE address
> taken and escaping), instead of all variables.  It was never meant to
> represent "completely unknown" (IE user has set pointer to  (char *)
> 0xdeadbeef).

Yes, is there a bitmap / array in the PTA graph that I can iterate
over instead of all vars?

> ISTM the set you union in should be based on CALLUSED and ESCAPED or
> something thereof, or at least should be computable with constraints
> during solving, and unioned in when it changes.

Ah, you mean whenever I see *ANYTHING = x union x into a new
STORE_TO_ANYTHING solution and have an explicit
*ANYTHING = STORE_TO_ANYTHING constraint (which I of course need
to handle properly in do_ds_constraint)?  That may be indeed faster.

> The way off the top of my head to do this is to simply stop using
> &ANYTHING, and use ANYTHING directly, and then have ANYTHING =
> CALLUSED and ANYTHING = ESCAPED.

I don't think CALLUSED or ESCAPED are related here.  You can store
non-addressables into *ANYTHING.

> Assuming you hate that idea for some reason
> 2. It's probably a lot faster to make a bitmap of these and update it,
> then union in the bitmap, than to iterate over all varinfos all the
> time.
> 
> ISTM you are trying to avoid doing #1 by adding all variables, even
> though this is going to give you worse than necessary results.
> 
> Intel actually iterates points-to solving in order to compute the set
> of nonlocal locations without explicitly adding the set everywhere.
> 
> See the description of nloc in section 4.1 of  "On the Importance of
> Points=To Analysis and Other
> Memory Disambiguation Methods For C Programs"

I'll have a look there.

Richard.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] [4.2/4.3/4.4 Regression] PTA constraint processing for *x = y is wrong

[dberlin at dberlin dot org]

------- Comment #15 from dberlin at gcc dot gnu dot org  2009-02-04 16:37 -------
Subject: Re:  [4.2/4.3/4.4 Regression] PTA 
        constraint processing for *x = y is wrong

On Wed, Feb 4, 2009 at 11:26 AM, rguenther at suse dot de
<gcc-bugzilla@gcc.gnu.org> wrote:
>
>
> ------- Comment #14 from rguenther at suse dot de  2009-02-04 16:26 -------
> Subject: Re:  [4.2/4.3/4.4 Regression] PTA
>  constraint processing for *x = y is wrong
>
> On Wed, 4 Feb 2009, dberlin at dberlin dot org wrote:
>
>> ------- Comment #13 from dberlin at gcc dot gnu dot org  2009-02-04 16:09 -------
>> Subject: Re:  PTA constraint processing for *x =
>>         y is wrong
>>
>> I don't remember offhand.  At one point during 4.2 we used to compute
>> the anything set exactly, and it led to massive issues. Of course,
>> most of those were because the anything set had hundreds or thousands
>> of SFT's :).
>>
>> I'm happy to go with your idea for fixing since fixing shortcutting
>> won't fix it, except for two things:
>> 1. ANYTHING is really limited to all addressable variables (IE address
>> taken and escaping), instead of all variables.  It was never meant to
>> represent "completely unknown" (IE user has set pointer to  (char *)
>> 0xdeadbeef).
>
> Yes, is there a bitmap / array in the PTA graph that I can iterate
> over instead of all vars?
Not right now.

>
>> ISTM the set you union in should be based on CALLUSED and ESCAPED or
>> something thereof, or at least should be computable with constraints
>> during solving, and unioned in when it changes.
>
> Ah, you mean whenever I see *ANYTHING = x union x into a new
> STORE_TO_ANYTHING solution and have an explicit
> *ANYTHING = STORE_TO_ANYTHING constraint (which I of course need
> to handle properly in do_ds_constraint)?  That may be indeed faster.
Something like that.
It is going to be faster than doing it one by one all the time.

>> The way off the top of my head to do this is to simply stop using
>> &ANYTHING, and use ANYTHING directly, and then have ANYTHING =
>> CALLUSED and ANYTHING = ESCAPED.
>
> I don't think CALLUSED or ESCAPED are related here.  You can store
> non-addressables into *ANYTHING.
How?
If they are non-addressable, that implies they are not pointed to.
I think you are going off the rails here :)
If you really want to union ANYTHING into things, the simplest way is
to change from doing:

ANYTHING = &ANYTHING
a = &y
p_4 = &ANYTHING
p_1 = p_4
p_1 = &a
x_6 = *p_1
derefaddrtmp.11 = &i
*x_6 = derefaddrtmp.11
y.0_7 = y

to
ANYTHING = *ANYTHING
ANYTHING = <all pointers pre-built or whatever we decided on>
a = &y
p_4 = ANYTHING
p_1 = p_4
p_1 = &a
x_6 = *p_1
derefaddrtmp.11 = &i
*x_6 = derefaddrtmp.11
y.0_7 = y

Then p_4 will get the entire anything set, and it will propagate
around just like you wanted.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] [4.2/4.3/4.4 Regression] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #16 from rguenth at gcc dot gnu dot org  2009-02-06 09:17 -------
Subject: Bug 39074

Author: rguenth
Date: Fri Feb  6 09:17:19 2009
New Revision: 143983

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=143983
Log:
2009-02-06  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/39074
        * tree-ssa-structalias.c (storedanything_id, var_storedanything,
        storedanything_tree): New.
        (do_ds_constraint): Simplify ANYTHING shortcutting.  Update
        the STOREDANYTHING solution if the lhs solution contains
        ANYTHING.
        (build_pred_graph): Add edges from STOREDANYTHING to all
        non-direct nodes.
        (get_constraint_for_1): CONSTRUCTOR
        is a zero-initializer.  Generate &NOTHING for it.
        (init_base_vars): Initialize STOREDANYTHING.
        (compute_points_to_sets): Free substitution info after
        building the succ graph.
        (ipa_pta_execute): Likewise.

        * gcc.dg/torture/pr39074.c: New testcase.
        * gcc.dg/torture/pr39074-2.c: Likewise.
        * gcc.dg/torture/pr39074-3.c: Likewise.

Added:
    branches/alias-improvements/gcc/testsuite/gcc.dg/torture/pr39074-2.c
    branches/alias-improvements/gcc/testsuite/gcc.dg/torture/pr39074-3.c
    branches/alias-improvements/gcc/testsuite/gcc.dg/torture/pr39074.c
Modified:
    branches/alias-improvements/gcc/ChangeLog.alias
    branches/alias-improvements/gcc/tree-ssa-structalias.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] [4.2/4.3/4.4 Regression] PTA constraint processing for *x = y is wrong

[jsm28 at gcc dot gnu dot org]

-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] [4.2/4.3/4.4 Regression] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #17 from rguenth at gcc dot gnu dot org  2009-02-19 10:12 -------
Subject: Bug 39074

Author: rguenth
Date: Thu Feb 19 10:12:25 2009
New Revision: 144292

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=144292
Log:
2009-02-19  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/39207
        PR tree-optimization/39074
        * tree-ssa-structalias.c (storedanything_id, var_storedanything,
        storedanything_tree): New.
        (do_ds_constraint): Simplify ANYTHING shortcutting.  Update
        the STOREDANYTHING solution if the lhs solution contains
        ANYTHING.
        (build_succ_graph): Add edges from STOREDANYTHING to all
        non-direct nodes.
        (init_base_vars): Initialize STOREDANYTHING.
        (compute_points_to_sets): Free substitution info after
        building the succ graph.
        (ipa_pta_execute): Likewise.

        * gcc.dg/torture/pr39074.c: New testcase.
        * gcc.dg/torture/pr39074-2.c: Likewise.
        * gcc.dg/torture/pr39074-3.c: Likewise.

        * tree-ssa-structalias.c (struct variable_info): Add may_have_pointers
        field.
        (do_ds_constraint): Do not add to special var or non-pointer
        field solutions.
        (type_could_have_pointers): Split out from ...
        (could_have_pointers): ... here.  For arrays use the element type.
        (create_variable_info_for): Initialize may_have_pointers.
        (new_var_info): Likewise.
        (handle_lhs_call): Make the HEAP variable unknown-sized.
        (intra_create_variable_infos): Use a type with pointers for
        PARM_NOALIAS, make it unknown-sized.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr39074-2.c
    trunk/gcc/testsuite/gcc.dg/torture/pr39074-3.c
    trunk/gcc/testsuite/gcc.dg/torture/pr39074.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-structalias.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] [4.2/4.3 Regression] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #18 from rguenth at gcc dot gnu dot org  2009-02-19 10:13 -------
Fixed on the trunk as well.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|4.1.3 4.2.4 4.3.3 4.4.0     |4.1.3 4.2.4 4.3.3
      Known to work|4.0.4                       |4.0.4 4.4.0
            Summary|[4.2/4.3/4.4 Regression] PTA|[4.2/4.3 Regression] PTA
                   |constraint processing for *x|constraint processing for *x
                   |= y is wrong                |= y is wrong


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] [4.3 Regression] PTA constraint processing for *x = y is wrong

[jsm28 at gcc dot gnu dot org]

------- Comment #19 from jsm28 at gcc dot gnu dot org  2009-03-31 21:09 -------
Closing 4.2 branch.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[4.2/4.3 Regression] PTA    |[4.3 Regression] PTA
                   |constraint processing for *x|constraint processing for *x
                   |= y is wrong                |= y is wrong
   Target Milestone|4.2.5                       |4.3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074

[Bug tree-optimization/39074] [4.3 Regression] PTA constraint processing for *x = y is wrong

[rguenth at gcc dot gnu dot org]

------- Comment #20 from rguenth at gcc dot gnu dot org  2009-06-17 12:34 -------
WONTFIX for 4.3.  Alias fixes are considered too risky at this stage.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|4.3.4                       |4.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39074