[Bug optimization/14749] New: Miscompilation of bit test

[Bug optimization/14749] New: Miscompilation of bit test

[steven at gcc dot gnu dot org]

The following test case is miscompiled by GCC 3.3.3 and earlier 
at -O and higher:  
  
inline void bar (const int id) { if (id & 0x00008000) abort (); }  
int main (void) { bar (0x00000001); return 0; }  
  
Apparently more or less by accident, this problem was fixed on mainline with  
the following patches:   
  
2003-07-04  Jeff Law  <law@redhat.com>  
  
        PR c/11428  
        * expr.c (do_store_flag): Pass in the correct result type  
        when calling fold_single_bit_test.  
        * fold-const.c (fold_single_bit_test): Use result_type for the  
        result when folding a sign bit test.  
  
2003-07-02  Jeff Law  <law@redhat.com>  
  
        * expr.c (do_store_flag): Remove special case folding for  
        single bit tests.  Instead call back into the commonized folder  
        routine.  
        * fold-const.c (fold_single_bit_test): New function, mostly  
        extracted from do_store_flag, with an additional case extracted  
        from fold.  
        (fold): Call fold_single_bit_test appropriately.  
        * tree.h (fold_single_bit_test): Prototype.  
  
I'd like to backport those for 3.3.4.

-- 
           Summary: Miscompilation of bit test
           Product: gcc
           Version: 3.3.3
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P1
         Component: optimization
        AssignedTo: steven at gcc dot gnu dot org
        ReportedBy: steven at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org,gdr at integrable-
                    solutions dot net,law at redhat dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

[Bug optimization/14749] Miscompilation of bit test

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2004-03-27 00:19 -------
Created an attachment (id=6000)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=6000&action=view)
Backport two patches from mainline

Bootstrapped on amd64, ppc, and i686.  Tested on amd64 and i686.  I'll post it
to gcc-patches this weekend.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

[Bug optimization/14749] Miscompilation of bit test

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-27 00:24 -------
Confirmed, already by me on IRC.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|                            |1
      Known to fail|                            |3.2.3 3.3.3
      Known to work|                            |3.0.4 2.95.3 3.4.0 3.5.0
   Last reconfirmed|0000-00-00 00:00:00         |2004-03-27 00:24:05
               date|                            |
   Target Milestone|---                         |3.3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

Re: [Bug optimization/14749] New: Miscompilation of bit test

[Gabriel Dos Reis]

"steven at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| The following test case is miscompiled by GCC 3.3.3 and earlier 
| at -O and higher:  
|   
| inline void bar (const int id) { if (id & 0x00008000) abort (); }  
| int main (void) { bar (0x00000001); return 0; }  
|   
| Apparently more or less by accident, this problem was fixed on mainline with  
| the following patches:   
|   
| 2003-07-04  Jeff Law  <law@redhat.com>  
|   
|         PR c/11428  
|         * expr.c (do_store_flag): Pass in the correct result type  
|         when calling fold_single_bit_test.  
|         * fold-const.c (fold_single_bit_test): Use result_type for the  
|         result when folding a sign bit test.  
|   
| 2003-07-02  Jeff Law  <law@redhat.com>  
|   
|         * expr.c (do_store_flag): Remove special case folding for  
|         single bit tests.  Instead call back into the commonized folder  
|         routine.  
|         * fold-const.c (fold_single_bit_test): New function, mostly  
|         extracted from do_store_flag, with an additional case extracted  
|         from fold.  
|         (fold): Call fold_single_bit_test appropriately.  
|         * tree.h (fold_single_bit_test): Prototype.  
|   
| I'd like to backport those for 3.3.4.

It is OK.  Thanks for identifying those!.

-- Gaby

[Bug optimization/14749] [3.3 Regression] Miscompilation of bit test

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-03-27 00:47 -------
Subject: Re:  New: Miscompilation of bit test

"steven at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| The following test case is miscompiled by GCC 3.3.3 and earlier 
| at -O and higher:  
|   
| inline void bar (const int id) { if (id & 0x00008000) abort (); }  
| int main (void) { bar (0x00000001); return 0; }  
|   
| Apparently more or less by accident, this problem was fixed on mainline with  
| the following patches:   
|   
| 2003-07-04  Jeff Law  <law@redhat.com>  
|   
|         PR c/11428  
|         * expr.c (do_store_flag): Pass in the correct result type  
|         when calling fold_single_bit_test.  
|         * fold-const.c (fold_single_bit_test): Use result_type for the  
|         result when folding a sign bit test.  
|   
| 2003-07-02  Jeff Law  <law@redhat.com>  
|   
|         * expr.c (do_store_flag): Remove special case folding for  
|         single bit tests.  Instead call back into the commonized folder  
|         routine.  
|         * fold-const.c (fold_single_bit_test): New function, mostly  
|         extracted from do_store_flag, with an additional case extracted  
|         from fold.  
|         (fold): Call fold_single_bit_test appropriately.  
|         * tree.h (fold_single_bit_test): Prototype.  
|   
| I'd like to backport those for 3.3.4.

It is OK.  Thanks for identifying those!.

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

[Bug optimization/14749] [3.3 Regression] Miscompilation of bit test

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-03-27 01:14 -------
Subject: Re:  Miscompilation of bit test

"pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| Confirmed, already by me on IRC.

I'm sorry, I can't follow discussions on IRC (e.g. I'm just back from 
office, reading through mails, approving patches, making a status
report before taking a flight to a conference in Europe in about 12
hours, and I don't expect to have regular connections there to be on
IRC).   

I would suggest that discussions by GCC developers that affect GCC be
held on GCC mailing lists.  Or at least, make an archive of those
discussions (even if that means some people would have tp refrain
from using some "words").

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

Re: [Bug optimization/14749] Miscompilation of bit test

[Gabriel Dos Reis]

"pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| Confirmed, already by me on IRC.

I'm sorry, I can't follow discussions on IRC (e.g. I'm just back from 
office, reading through mails, approving patches, making a status
report before taking a flight to a conference in Europe in about 12
hours, and I don't expect to have regular connections there to be on
IRC).   

I would suggest that discussions by GCC developers that affect GCC be
held on GCC mailing lists.  Or at least, make an archive of those
discussions (even if that means some people would have tp refrain
from using some "words").

-- Gaby

[Bug optimization/14749] [3.3 Regression] Miscompilation of bit test

[stevenb at suse dot de]

------- Additional Comments From stevenb at suse dot de  2004-03-27 01:28 -------
Subject: Re:  [3.3 Regression] Miscompilation of bit test

On Saturday 27 March 2004 02:14, gdr at integrable-solutions dot net wrote:
> ------- Additional Comments From gdr at integrable-solutions dot net 
> 2004-03-27 01:14 ------- Subject: Re:  Miscompilation of bit test
>
> "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:
> | Confirmed, already by me on IRC.
>
> I'm sorry, I can't follow discussions on IRC (e.g. I'm just back from
> office, reading through mails, approving patches, making a status
> report before taking a flight to a conference in Europe in about 12
> hours, and I don't expect to have regular connections there to be on
> IRC).
>
> I would suggest that discussions by GCC developers that affect GCC be
> held on GCC mailing lists.  Or at least, make an archive of those
> discussions (even if that means some people would have tp refrain
> from using some "words").

What discussion? What "words"?

I just pasted the test case into an IRC channel so that Andrew Pinski
could confirm the bug.  I like this kind of direct communication, so
if you don't mind, I'll keep doing things that way and post relevant
information (ie. results from such "discussions") to gcc mailing lists
and/or bugzilla.

I don't ask you to follow IRC, and you should not tell us not to use it.



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

[Bug optimization/14749] [3.3 Regression] Miscompilation of bit test

[gdr at integrable-solutions dot net]

------- Additional Comments From gdr at integrable-solutions dot net  2004-03-27 02:09 -------
Subject: Re:  [3.3 Regression] Miscompilation of bit test

"stevenb at suse dot de" <gcc-bugzilla@gcc.gnu.org> writes:

| On Saturday 27 March 2004 02:14, gdr at integrable-solutions dot net wrote:
| > ------- Additional Comments From gdr at integrable-solutions dot net 
| > 2004-03-27 01:14 ------- Subject: Re:  Miscompilation of bit test
| >
| > "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:
| > | Confirmed, already by me on IRC.
| >
| > I'm sorry, I can't follow discussions on IRC (e.g. I'm just back from
| > office, reading through mails, approving patches, making a status
| > report before taking a flight to a conference in Europe in about 12
| > hours, and I don't expect to have regular connections there to be on
| > IRC).
| >
| > I would suggest that discussions by GCC developers that affect GCC be
| > held on GCC mailing lists.  Or at least, make an archive of those
| > discussions (even if that means some people would have tp refrain
| > from using some "words").
| 
| What discussion? What "words"?
| 
| I just pasted the test case into an IRC channel so that Andrew Pinski
| could confirm the bug.  I like this kind of direct communication, so
| if you don't mind, I'll keep doing things that way and post relevant
| information (ie. results from such "discussions") to gcc mailing lists
| and/or bugzilla.
| 
| I don't ask you to follow IRC, and you should not tell us not to use it.

Did you carefully read what I said, you would have noticed that I did
not ask you to stop using IRC.  Wouldn't you?

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

Re: [Bug optimization/14749] [3.3 Regression] Miscompilation of bit test

[Gabriel Dos Reis]

"stevenb at suse dot de" <gcc-bugzilla@gcc.gnu.org> writes:

| On Saturday 27 March 2004 02:14, gdr at integrable-solutions dot net wrote:
| > ------- Additional Comments From gdr at integrable-solutions dot net 
| > 2004-03-27 01:14 ------- Subject: Re:  Miscompilation of bit test
| >
| > "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:
| > | Confirmed, already by me on IRC.
| >
| > I'm sorry, I can't follow discussions on IRC (e.g. I'm just back from
| > office, reading through mails, approving patches, making a status
| > report before taking a flight to a conference in Europe in about 12
| > hours, and I don't expect to have regular connections there to be on
| > IRC).
| >
| > I would suggest that discussions by GCC developers that affect GCC be
| > held on GCC mailing lists.  Or at least, make an archive of those
| > discussions (even if that means some people would have tp refrain
| > from using some "words").
| 
| What discussion? What "words"?
| 
| I just pasted the test case into an IRC channel so that Andrew Pinski
| could confirm the bug.  I like this kind of direct communication, so
| if you don't mind, I'll keep doing things that way and post relevant
| information (ie. results from such "discussions") to gcc mailing lists
| and/or bugzilla.
| 
| I don't ask you to follow IRC, and you should not tell us not to use it.

Did you carefully read what I said, you would have noticed that I did
not ask you to stop using IRC.  Wouldn't you?

-- Gaby

[Bug optimization/14749] [3.3 Regression] Miscompilation of bit test

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2004-03-27 22:36 -------
(From update of attachment 6000)
The proposed patch caused 14754, so I'll have to withdraw that patch.  I'm
looking at other ways to fix the issue.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
Attachment #6000 is|0                           |1
           obsolete|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

[Bug optimization/14749] [3.3 Regression] Miscompilation of bit test

[gdr at gcc dot gnu dot org]

------- Additional Comments From gdr at gcc dot gnu dot org  2004-04-27 07:01 -------
(In reply to comment #7)
> (From update of attachment 6000)
> The proposed patch caused 14754, so I'll have to withdraw that patch.  I'm
> looking at other ways to fix the issue.
> 

Steven --

  Did you make a progress on this front?

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

[Bug optimization/14749] [3.3 Regression] Miscompilation of bit test

[s dot bosscher at student dot tudelft dot nl]

------- Additional Comments From s dot bosscher at student dot tudelft dot nl  2004-04-27 08:22 -------
Subject: RE:  [3.3 Regression] Miscompilation of b
	it test

Yes, I have a stop-gap, but I can't get to it until I can revive my machine.
I'll send it to you next week.

-----Original Message-----
From: gdr at gcc dot gnu dot org
To: steven@gcc.gnu.org
Sent: 4/27/04 9:01 AM
Subject: [Bug optimization/14749] [3.3 Regression] Miscompilation of bit
test


------- Additional Comments From gdr at gcc dot gnu dot org  2004-04-27
07:01 -------
(In reply to comment #7)
> (From update of attachment 6000)
> The proposed patch caused 14754, so I'll have to withdraw that patch.
I'm
> looking at other ways to fix the issue.
> 

Steven --

  Did you make a progress on this front?

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

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-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

[Bug optimization/14749] [3.3 Regression] Miscompilation of bit test

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2004-05-07 16:26 -------
I'm not going to say "fixed".  Just "plugged". 

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749

[Bug optimization/14749] [3.3 Regression] Miscompilation of bit test

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-05-07 16:26 -------
Subject: Bug 14749

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-3_3-branch
Changes by:	steven@gcc.gnu.org	2004-05-07 16:26:04

Modified files:
	gcc            : expr.c ChangeLog 

Log message:
	PR opt/14749
	* expr.c (do_jump): If TREE_CONSTANT_OVERFLOW is set, don't
	trust integer_zerop.  Just expand both branches.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/expr.c.diff?cvsroot=gcc&only_with_tag=gcc-3_3-branch&r1=1.498.2.29&r2=1.498.2.30
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_3-branch&r1=1.16114.2.975&r2=1.16114.2.976



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14749