[Bug fortran/13037] New: regression: g77 generates incorrect code

[Bug fortran/13037] New: regression: g77 generates incorrect code

[smelkov at mph1 dot phys dot spbu dot ru]

I've discovered a bug (incorrect code generation) in g77 from gcc-3.3.2 
bug symptom: zeta(kkzc) seems to reference to zeta(kkzc-1) instead 
with gcc-3.2.2 it is OK, so it is a regression. 
 
      subroutine bug1(expnt) 
      implicit none 
 
      double precision zeta 
      common /bug1_area/zeta(3) 
 
      double precision expnt(3) 
 
 
      integer k, kkzc 
 
      kkzc=0 
      do k=1,3 
         kkzc = kkzc + 1 
         zeta(kkzc) = expnt(k) 
      enddo 
 
c     the following line activates the bug 
      call bug1_activator(kkzc) 
      end 
 
full bug1.f source is in attachment

-- 
           Summary: regression: g77 generates incorrect code
           Product: gcc
           Version: 3.3.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: smelkov at mph1 dot phys dot spbu dot ru
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug fortran/13037] regression: g77 generates incorrect code

[smelkov at mph1 dot phys dot spbu dot ru]

------- Additional Comments From smelkov at mph1 dot phys dot spbu dot ru  2003-11-13 12:49 -------
Created an attachment (id=5129)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5129&action=view)
full source attachment for bug 13037


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug fortran/13037] regression: g77 generates incorrect code

[smelkov at mph1 dot phys dot spbu dot ru]

------- Additional Comments From smelkov at mph1 dot phys dot spbu dot ru  2003-11-13 12:54 -------
forgot to include gcc info: 
 
[kirr@roro tmini]$ g77 -v 
Reading specs from /mnt/tmini/kirr/local/gcc-3.3.2/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/specs 
Configured with: ../gcc-3.3.2/configure --prefix=/mnt/tmini/kirr/local/gcc-3.3.2 --with-gnu-as 
--with-gnu-ld --enable-threads=posix --enable-languages=c,c++,f77 --enable-checking 
--disable-nls 
Thread model: posix 
gcc version 3.3.2 
 

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug fortran/13037] regression: g77 generates incorrect code

[bdavis9659 at comcast dot net]

------- Additional Comments From bdavis9659 at comcast dot net  2003-11-14 04:41 -------
Not too sure exactly what the problem is.  Please take your code snippet and
make it into an example that compiles and executes, then we can see exactly what
the problem is.

I took the liberty of creating one from your code snippets:

      subroutine bug1(expnt)
      implicit none
      double precision zeta
      common /bug1_area/zeta(3)
      double precision expnt(3)
      integer k, kkzc
      kkzc=0
      do k=1,3
         kkzc = kkzc + 1
         zeta(kkzc) = expnt(k)
      enddo
      print*,'kkzc = ',kkzc
      print*,'zeta =  (',(zeta(k),k=1,3),')'
      print*,'expnt = (',(expnt(k),k=1,3),')'
      return
      end
c     the following line activates the bug
      program test
      implicit none
      double precision kkzc(3)
      kkzc(1) = 1
      kkzc(2) = 2
      kkzc(3) = 3
      call bug1(kkzc)
      end

and then show a run of the program:

[bdavis@localhost ~]$ ./a.out
 kkzc =  3
 zeta =  (  1.  2.  3.)
 expnt = (  1.  2.  3.)


 

regards,
bud davis


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug fortran/13037] regression: g77 generates incorrect code

[smelkov at mph1 dot phys dot spbu dot ru]

------- Additional Comments From smelkov at mph1 dot phys dot spbu dot ru  2003-11-14 17:03 -------
Ok, i swear i'll never provide examples as attachment! :) 
 
here it is: 
---bug1.f--- 
c     g77 -O2 bug1.f -o bug1 
c     ./bug1 
c 
c     long story: I've discovered a bug (incorrect code generation) in g77 from gcc-3.3.2 
c     bug symptom: zeta(kkzc) seems to reference to zeta(kkzc-1) instead 
c     with gcc-3.2.2 it is OK, so it is a regression. 
c      
      subroutine bug1(expnt) 
      implicit none 
 
      double precision zeta 
      common /bug1_area/zeta(3) 
 
      double precision expnt(3) 
 
 
      integer k, kkzc 
 
      kkzc=0 
      do k=1,3 
         kkzc = kkzc + 1 
         zeta(kkzc) = expnt(k) 
      enddo 
 
c     the following line activates the bug 
      call bug1_activator(kkzc) 
      end 
 
 
c     dummy subroutine 
      subroutine bug1_activator(inum) 
      implicit none 
      integer inum 
      end 
 
 
c     test driver 
      program test_bug1 
      implicit none 
 
      double precision zeta 
      common /bug1_area/zeta(3) 
 
      double precision expnt(3) 
 
      zeta(1) = 0.0d0 
      zeta(2) = 0.0d0 
      zeta(3) = 0.0d0 
 
      expnt(1) = 1.0d0 
      expnt(2) = 2.0d0 
      expnt(3) = 3.0d0 
 
      call bug1(expnt) 
      write(*,*) zeta(1), zeta(2), zeta(3) 
 
      if (zeta(1).ne.1) then 
        write(*,*) 'BUG!' 
        call exit(1) 
      endif 
 
      end 
--- end of bug1.f--- 
 
[kirr@roro /mnt/tmini]$ ./bug1  
  2.  3.  0. 
 BUG! 
 

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression]: g77 generates incorrect code

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2003-11-15 09:35 -------
I can confirm this but it is fixed on the mainline already but since this is a regression, keeping open 
untill the 3.3 branch gets fixed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
          Component|fortran                     |optimization
     Ever Confirmed|                            |1
           Keywords|                            |wrong-code
   Last reconfirmed|0000-00-00 00:00:00         |2003-11-15 09:35:11
               date|                            |
            Summary|regression: g77 generates   |[3.3 regression]: g77
                   |incorrect code              |generates incorrect code
   Target Milestone|---                         |3.3.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2003-11-15 09:38 -------
It is gcse load motion which is causing this.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[3.3 regression]: g77       |[3.3 regression] [gcse-lm]
                   |generates incorrect code    |g77 generates incorrect code


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2003-11-15 09:39 -------
Related to bug 12442.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[smelkov at mph1 dot phys dot spbu dot ru]

------- Additional Comments From smelkov at mph1 dot phys dot spbu dot ru  2003-11-15 09:50 -------
Maybe it's worth adding it to g77 testcases? 
 

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[janis187 at us dot ibm dot com]

------- Additional Comments From janis187 at us dot ibm dot com  2003-12-02 00:29 -------
The regression in PR 13037 was fixed on the mainline with this patch:

2003-04-18  Hans-Peter Nilsson  <hp@bitrange.com>

      * gcse.c (compute_ld_motion_mems): For MEM destinations, only
      consider those to be movable where the source matches
      want_to_gcse_p.
      (update_ld_motion_stores): In comment, refer to
      compute_ld_motion_mems for validity of replacement.

Roger Sayle asked me to identify the fix on the mainline so he can
port it to the 3.3 branch.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[ebotcazou at gcc dot gnu dot org]

------- Additional Comments From ebotcazou at gcc dot gnu dot org  2003-12-03 09:43 -------
Roger, it appears that you already took a look at this one and are considering a
backport patch from mainline, so I take the liberty to assign it to you.  Let me
know if you disagree.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |sayle at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[roger at eyesopen dot com]

------- Additional Comments From roger at eyesopen dot com  2003-12-09 11:49 -------
There's a patch at http://gcc.gnu.org/ml/gcc-patches/2003-12/msg00668.html
that's still awaiting review :>

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[ebotcazou at gcc dot gnu dot org]

------- Additional Comments From ebotcazou at gcc dot gnu dot org  2003-12-09 11:54 -------
I'd almost qualify it as obvious.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[ebotcazou at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |critical


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[ebotcazou at gcc dot gnu dot org]

------- Additional Comments From ebotcazou at gcc dot gnu dot org  2003-12-11 11:26 -------
*** Bug 12442 has been marked as a duplicate of this bug. ***

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2003-12-12 14:31 -------
Subject: Bug 13037

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	sayle@gcc.gnu.org	2003-12-12 14:31:18

Modified files:
	gcc            : ChangeLog loop.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/g77.f-torture/execute: 13037.f 

Log message:
	PR optimization/13037
	* loop.c (update_giv_derive): Ignore redundant sets of a biv when
	calculating how to derive a giv from a biv.
	
	* g77.f-torture/execute/13037.f: New test case.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.1986&r2=2.1987
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/loop.c.diff?cvsroot=gcc&r1=1.478&r2=1.479
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.3247&r2=1.3248
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g77.f-torture/execute/13037.f.diff?cvsroot=gcc&r1=NONE&r2=1.1



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2003-12-12 18:37 -------
Subject: Bug 13037

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-3_3-branch
Changes by:	sayle@gcc.gnu.org	2003-12-12 18:37:07

Modified files:
	gcc            : ChangeLog loop.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/g77.f-torture/execute: 13037.f 

Log message:
	PR optimization/13037
	* loop.c (update_giv_derive): Ignore redundant sets of a biv when
	calculating how to derive a giv from a biv.
	
	* g77.f-torture/execute/13037.f: New test case.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_3-branch&r1=1.16114.2.842&r2=1.16114.2.843
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/loop.c.diff?cvsroot=gcc&only_with_tag=gcc-3_3-branch&r1=1.433.2.10&r2=1.433.2.11
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_3-branch&r1=1.2261.2.334&r2=1.2261.2.335
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g77.f-torture/execute/13037.f.diff?cvsroot=gcc&only_with_tag=gcc-3_3-branch&r1=NONE&r2=1.1.2.1



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037

[Bug optimization/13037] [3.3 regression] [gcse-lm] g77 generates incorrect code

[ebotcazou at gcc dot gnu dot org]

------- Additional Comments From ebotcazou at gcc dot gnu dot org  2003-12-13 08:36 -------
See the aforementioned patch.


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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13037