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From: "dominiq at lps dot ens dot fr" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/42181] [4.5 Regression][graphite] -fgraphite-identity miscompiles air.f90
Date: Tue, 09 Mar 2010 13:32:00 -0000	[thread overview]
Message-ID: <20100309133215.12595.qmail@sourceware.org> (raw)
In-Reply-To: <bug-42181-11113@http.gcc.gnu.org/bugzilla/>



------- Comment #22 from dominiq at lps dot ens dot fr  2010-03-09 13:32 -------
The following variant of spectop.f90 is miscompiled with '-fgraphite-identity
-O3':

      SUBROUTINE SPECTOP(Dr,N)
      IMPLICIT REAL*8(A-H,o-Z)
      DIMENSION d1(0:32,0:32) , Dr(0:32,0:32) , x(0:32)
      REAL*8 Dr
!
! PROGRAM TO COMPUTE THE CHEBYSHEV SPECTRAL OPERATOR
!
      ang = DBLE(1)
      s = DBLE(6)
      o = DBLE(1)
      t = DBLE(2)
      pi = t*DASIN(ang)
      DO i = 0 , N
         x(i) = DCOS(pi*DBLE(i)/DBLE(N))
      ENDDO
!
! IF J=K
!
      DO j = 1 , N - 1
         d1(j,j) = -x(j)/(t*(o-x(j)**2))
      ENDDO
      d1(0,0) = (t*DBLE(N)**2+o)/s
      d1(N,N) = -d1(0,0)
!
! IF J.NE.K
!
      fctr = -t
      DO j = 1 , N-1
         d1(0,j) = fctr/(x(0)-x(j))
         fctr = -fctr
      ENDDO
      d1(0,N) = fctr/(t*(x(0)-x(N)))
      fctr1 = -1.0D0
      DO k = 1 , N-1
         d1(k,0) = fctr1/(t*(x(k)-x(0)))
         fctr = -fctr1
         DO j = 1 , N-1
            if (j.ne.k) d1(k,j) = fctr/(x(k)-x(j))
            fctr = -fctr
         ENDDO
         d1(k,N) = fctr/(t*(x(k)-x(N)))
         fctr1 = -fctr1
      ENDDO
      d1(N,0) = fctr1/(x(N)-x(0))
      fctr = -t*fctr1
      DO j = 1 , N-1
         d1(N,j) = fctr/(x(N)-x(j))
         fctr = -fctr
      ENDDO
      DO k = 0 , N
         DO j = 0 , N
            Dr(k,j) = d1(N-k,N-j)
         ENDDO
      ENDDO
      CONTINUE
      END

but is correctly compiled if 

         DO j = 1 , N-1
            if (j.ne.k) d1(k,j) = fctr/(x(k)-x(j))
            fctr = -fctr
         ENDDO

is replaced with

         DO j = 1 , k-1
            d1(k,j) = fctr/(x(k)-x(j))
            fctr = -fctr
         ENDDO
         fctr = -fctr
         DO j = k+1 , N-1
            d1(k,j) = fctr/(x(k)-x(j))
            fctr = -fctr
         ENDDO


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42181


  parent reply	other threads:[~2010-03-09 13:32 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-26  2:53 [Bug middle-end/42181] New: -fgraphite-identity miscompiles or ICEs on air.f90 howarth at nitro dot med dot uc dot edu
2009-11-26 17:03 ` [Bug middle-end/42181] " jv244 at cam dot ac dot uk
2009-11-26 17:04 ` jv244 at cam dot ac dot uk
2009-11-26 17:05 ` [Bug middle-end/42181] [4.5 Regression] " jv244 at cam dot ac dot uk
2009-11-27 11:32 ` rguenth at gcc dot gnu dot org
2009-12-14 19:03 ` spop at gcc dot gnu dot org
2009-12-14 19:03 ` spop at gcc dot gnu dot org
2009-12-23  7:50 ` spop at gcc dot gnu dot org
2009-12-24  0:14 ` howarth at nitro dot med dot uc dot edu
2009-12-24  0:15 ` howarth at nitro dot med dot uc dot edu
2009-12-24  0:18 ` howarth at nitro dot med dot uc dot edu
2009-12-24  0:20 ` howarth at nitro dot med dot uc dot edu
2009-12-24  8:13 ` dominiq at lps dot ens dot fr
2010-01-14 16:57 ` trifunovic at gcc dot gnu dot org
2010-01-14 19:25 ` spop at gcc dot gnu dot org
2010-02-06 17:44 ` [Bug middle-end/42181] [4.5 Regression][graphite] " spop at gcc dot gnu dot org
2010-03-08 23:09 ` [Bug middle-end/42181] [4.5 Regression][graphite] -fgraphite-identity miscompiles air.f90 howarth at nitro dot med dot uc dot edu
2010-03-08 23:16 ` spop at gcc dot gnu dot org
2010-03-09  2:26 ` howarth at nitro dot med dot uc dot edu
2010-03-09  2:34 ` howarth at nitro dot med dot uc dot edu
2010-03-09  2:35 ` howarth at nitro dot med dot uc dot edu
2010-03-09  2:37 ` howarth at nitro dot med dot uc dot edu
2010-03-09  3:45 ` howarth at nitro dot med dot uc dot edu
2010-03-09  3:49 ` howarth at nitro dot med dot uc dot edu
2010-03-09 13:32 ` dominiq at lps dot ens dot fr [this message]
2010-03-09 22:31 ` spop at gcc dot gnu dot org
2010-03-14 11:40 ` dominiq at lps dot ens dot fr
2010-03-20 10:45 ` dominiq at lps dot ens dot fr
2010-03-21 16:28   ` Sebastian Pop
2010-03-21 16:28 ` sebpop at gmail dot com
2010-03-23 20:08 ` spop at gcc dot gnu dot org
2010-03-23 21:24 ` spop at gcc dot gnu dot org
2010-03-23 21:28 ` spop at gcc dot gnu dot org
2010-03-24 20:18 ` spop at gcc dot gnu dot org
2010-03-24 21:35 ` howarth at nitro dot med dot uc dot edu
2010-03-25 17:43   ` Sebastian Pop
2010-03-26  9:58     ` Richard Guenther
2010-03-25 17:44 ` sebpop at gmail dot com
2010-03-26  9:58 ` rguenther at suse dot de

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