[Bug ada/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[Bug ada/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[laurent at guerby dot net]

------- Comment #10 from laurent at guerby dot net  2005-10-02 16:20 -------
It looks like it is indeed a codegen bug in s-arit64.adb, in Scaled_Divide the
following line is miscompiled at -O1 and above (works at -O0):

            T2 := Lo (T1 rem Zlo) & D (4);

In my p.adb testcase, the compiler with Jan patch calls Lo with argument = 0
whereas (T1 rem Zlo) returned (1073741824 rem 3221225472) = 1073741824 so
stack/argument handling must be confused at some point. 

The bug is volatile, ie replacing the line above by:

            S3 := Lo (T1 rem Zlo);
            if S3 = 0 then
               T2 := Uns64 (D (4));
            else
               T2 := S3 & D (4);
            end if;

Makes it go away.

Laurent


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug ada/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[hubicka at ucw dot cz]

------- Comment #11 from hubicka at ucw dot cz  2005-10-02 21:46 -------
Subject: Re:  [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed
and decimal arithmetic broken

> 
> 
> ------- Comment #10 from laurent at guerby dot net  2005-10-02 16:20 -------
> It looks like it is indeed a codegen bug in s-arit64.adb, in Scaled_Divide the
> following line is miscompiled at -O1 and above (works at -O0):
> 
>             T2 := Lo (T1 rem Zlo) & D (4);
> 
> In my p.adb testcase, the compiler with Jan patch calls Lo with argument = 0
> whereas (T1 rem Zlo) returned (1073741824 rem 3221225472) = 1073741824 so
> stack/argument handling must be confused at some point. 
> 
> The bug is volatile, ie replacing the line above by:
> 
>             S3 := Lo (T1 rem Zlo);
>             if S3 = 0 then
>                T2 := Uns64 (D (4));
>             else
>                T2 := S3 & D (4);
>             end if;
> 
> Makes it go away.
Can you please check if -fno-tree-ter makes the bug go away?  We've
chatted recently with Jakub concerning bug in argument saving in nested
call and -maccumulate-outgoing-args.  I was under impression that we
should no longer produce the nested calls out of ter but aparently it is
still being done (that results in inferrior code quality too as we can't
generated nested calls very sanely)

Also can you also, please, point me closer to place in .optimized dump
where the misscompilation happens?  THere seems to be couple of lo calls
around.  I will be mostly offline tomorrow but should be able to fix it
day after that.

Thanks a lot!
Honza


-- 


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[Bug ada/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[ebotcazou at gcc dot gnu dot org]

------- Comment #12 from ebotcazou at gcc dot gnu dot org  2005-10-02 21:55 -------
> Can you please check if -fno-tree-ter makes the bug go away?  We've
> chatted recently with Jakub concerning bug in argument saving in nested
> call and -maccumulate-outgoing-args.  I was under impression that we
> should no longer produce the nested calls out of ter but aparently it is
> still being done (that results in inferrior code quality too as we can't
> generated nested calls very sanely)

To back up your hypothesis, I can say that I'm *not* seeing the failures on
i586.


-- 

ebotcazou at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug ada/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[hubicka at ucw dot cz]

------- Comment #13 from hubicka at ucw dot cz  2005-10-02 22:30 -------
Subject: Re:  [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed
and decimal arithmetic broken

> 
> 
> ------- Comment #12 from ebotcazou at gcc dot gnu dot org  2005-10-02 21:55 -------
> > Can you please check if -fno-tree-ter makes the bug go away?  We've
> > chatted recently with Jakub concerning bug in argument saving in nested
> > call and -maccumulate-outgoing-args.  I was under impression that we
> > should no longer produce the nested calls out of ter but aparently it is
> > still being done (that results in inferrior code quality too as we can't
> > generated nested calls very sanely)
> 
> To back up your hypothesis, I can say that I'm *not* seeing the failures on
> i586.
That seems consistent.  i586 defaults to -mno-accumulate-outgoing-args.
const int x86_accumulate_outgoing_args = m_ATHLON_K8 | m_PENT4 | m_NOCONA |
m_PPRO;


Honza
> 
> 
> -- 
> 
> ebotcazou at gcc dot gnu dot org changed:
> 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                  CC|                            |ebotcazou at gcc dot gnu dot
>                    |                            |org
> 
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003
> 
> ------- You are receiving this mail because: -------
> You are on the CC list for the bug, or are watching someone who is.


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[Bug ada/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[laurent at guerby dot net]

------- Comment #14 from laurent at guerby dot net  2005-10-03 03:37 -------
I confirm that on p.adb no-tree-ter does make the problem disappear, p.adb
works when I compile s-arit64 as follows:

gcc -c -O2 -gnatpg -fno-tree-ter s-arit64.adb

(I'll be away from email until wednesday).


-- 


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[Bug middle-end/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[laurent at guerby dot net]

------- Comment #15 from laurent at guerby dot net  2005-10-05 20:08 -------
Created an attachment (id=9897)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=9897&action=view)
-fdump-rtl-expand-details

s-arit64.adb.00.expand-normal : -O2 -gnatpg
s-arit64.adb.00.expand-no-tree-ter : -O2 -gnatpg -fno-tree-ter

Limited to function Scaled_Divide.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug middle-end/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[pinskia at gcc dot gnu dot org]

------- Comment #16 from pinskia at gcc dot gnu dot org  2005-10-22 21:58 -------
This most likely can be produced using C code, just has not found a testcase
yet.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |critical
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug middle-end/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[ebotcazou at gcc dot gnu dot org]

------- Comment #17 from ebotcazou at gcc dot gnu dot org  2005-10-24 16:33 -------
Ouch! I cannot reproduce with a i586-suse-linux compiler configured with full
checking and gccflags="-O2 -march=i686".


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug middle-end/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[laurent at guerby dot net]

------- Comment #18 from laurent at guerby dot net  2005-10-24 19:37 -------
Still seeing the failures on SuSE 9.3 i686 machine with
"-enable-languages=ada,c --enable-__cxa_atexit --disable-nls
--enable-threads=posix --disable-multilib" --enable-checking as of:

LAST_UPDATED: Mon Oct 24 17:22:09 UTC 2005

I have some patches from Richard Kenner in my tree though. Eric, did you manage
to reproduce the problem at all? 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug middle-end/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[ebotcazou at gcc dot gnu dot org]

------- Comment #19 from ebotcazou at gcc dot gnu dot org  2005-10-24 21:05 -------
> I have some patches from Richard Kenner in my tree though. Eric, did you manage
> to reproduce the problem at all? 

Nein. :-)  But I'll try a bit harder tomorrow and on various machines.


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|ebotcazou at gcc dot gnu dot|
                   |org                         |
         AssignedTo|unassigned at gcc dot gnu   |ebotcazou at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-10-24 21:05:07
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug middle-end/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[laurent at guerby dot net]

------- Comment #20 from laurent at guerby dot net  2005-10-24 21:31 -------
Jan Hubicka told me on IRC that Jakub Jelinek is working on PR23775 which might
be related (or the same issue) as this one.


-- 


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[Bug middle-end/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[ebotcazou at gcc dot gnu dot org]

------- Comment #21 from ebotcazou at gcc dot gnu dot org  2005-10-25 09:26 -------
OK, confirmed with a pristine tree on i686.


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2005-10-24 21:05:07         |2005-10-25 09:26:23
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug middle-end/24003] [4.1 Regression] ACATS FAIL 17 regressions on x86-linux, fixed and decimal arithmetic broken

[ebotcazou at gcc dot gnu dot org]

------- Comment #22 from ebotcazou at gcc dot gnu dot org  2005-10-25 15:33 -------
Jan,

> Can you please check if -fno-tree-ter makes the bug go away?  We've
> chatted recently with Jakub concerning bug in argument saving in nested
> call and -maccumulate-outgoing-args.  I was under impression that we
> should no longer produce the nested calls out of ter but aparently it is
> still being done (that results in inferrior code quality too as we can't
> generated nested calls very sanely)

Would that be an acceptable fix (not rematerializing nested calls)?

> Also can you also, please, point me closer to place in .optimized dump
> where the misscompilation happens?

 <L12>:;
-  temp.456 = d[3]{lb: 1 sz: 4};
-  t1.427 = system__arith_64__Oconcat (temp.433, temp.456);
-  temp.460 = d[4]{lb: 1 sz: 4};
-  D.712 = system__arith_64__Orem (t1.427, zlo);
-  D.713 = system__arith_64__lo (D.712);
-  t2.450 = system__arith_64__Oconcat (D.713, temp.460);
-  D.715 = system__arith_64__Odivide (t2.450, zlo);
-  D.716 = system__arith_64__lo (D.715);
-  D.717 = system__arith_64__Odivide (t1.427, zlo);
-  D.718 = system__arith_64__lo (D.717);
-  qu = system__arith_64__Oconcat (D.718, D.716);
+  t1.427 = system__arith_64__Oconcat (temp.433, d[3]{lb: 1 sz: 4});
+  t2.450 = system__arith_64__Oconcat (system__arith_64__lo
(system__arith_64__Orem (t1.427, zlo)), d[4]{lb: 1 sz: 4});
+  qu = system__arith_64__Oconcat (system__arith_64__lo
(system__arith_64__Odivide (t1.427, zlo)), system__arith_64__lo
(system__arith_64__Odivide (t2.450, zlo)));
   ru = system__arith_64__Orem (t2.450, zlo);
   goto <bb 37> (<L50>);

-: -O1 -fno-tree-ter
+: -O1


-- 


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[Bug middle-end/24003] [4.1 Regression] 17 ACATS regressions (fixed point or decimal artihmetic)

[mmitchel at gcc dot gnu dot org]

------- Comment #23 from mmitchel at gcc dot gnu dot org  2005-10-31 05:52 -------
Do we have a C/C++ testcase for this problem?

I'm going to leave this as P2 for now, given that we think it's not
language-dependent, and given that we seem close to a fix.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug middle-end/24003] [4.1 Regression] 17 ACATS regressions (fixed point or decimal artihmetic)

[ebotcazou at gcc dot gnu dot org]

------- Comment #24 from ebotcazou at gcc dot gnu dot org  2005-11-11 07:43 -------
> Do we have a C/C++ testcase for this problem?

Yes, we do, attached.

> I'm going to leave this as P2 for now, given that we think it's not
> language-dependent, and given that we seem close to a fix.

Pretty serious bug indeed.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug middle-end/24003] [4.1 Regression] 17 ACATS regressions (fixed point or decimal artihmetic)

[ebotcazou at gcc dot gnu dot org]

------- Comment #25 from ebotcazou at gcc dot gnu dot org  2005-11-11 07:44 -------
Created an attachment (id=10212)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10212&action=view)
C testcase.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug middle-end/24003] [4.1 Regression] 17 ACATS regressions (fixed point or decimal artihmetic)

[ebotcazou at gcc dot gnu dot org]

------- Comment #26 from ebotcazou at gcc dot gnu dot org  2005-11-13 09:55 -------
Subject: Bug 24003

Author: ebotcazou
Date: Sun Nov 13 09:55:11 2005
New Revision: 106860

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=106860
Log:
        PR middle-end/24003
        * calls.c (expand_call): If TARGET is a MEM and some part of the
        argument area has been saved, force TARGET to a register.


Added:
    trunk/gcc/testsuite/gcc.dg/nested-calls-1.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/calls.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003

[Bug middle-end/24003] [4.1 Regression] 17 ACATS regressions (fixed point or decimal artihmetic)

[ebotcazou at gcc dot gnu dot org]

------- Comment #27 from ebotcazou at gcc dot gnu dot org  2005-11-13 09:57 -------
See http://gcc.gnu.org/ml/gcc-patches/2005-11/msg00807.html


-- 

ebotcazou at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24003