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! { dg-do compile { target i?86-*-* x86_64-*-* } }
! { dg-require-effective-target vect_double }
! { dg-require-effective-target sse2 }
! { dg-options "-O3 -ffast-math -msse2 -fpredictive-commoning -ftree-vectorize -fdump-tree-optimized" }
******* RESID COMPUTES THE RESIDUAL: R = V - AU
*
* THIS SIMPLE IMPLEMENTATION COSTS 27A + 4M PER RESULT, WHERE
* A AND M DENOTE THE COSTS OF ADDITION (OR SUBTRACTION) AND
* MULTIPLICATION, RESPECTIVELY. BY USING SEVERAL TWO-DIMENSIONAL
* BUFFERS ONE CAN REDUCE THIS COST TO 13A + 4M IN THE GENERAL
* CASE, OR 10A + 3M WHEN THE COEFFICIENT A(1) IS ZERO.
*
SUBROUTINE RESID(U,V,R,N,A)
INTEGER N
REAL*8 U(N,N,N),V(N,N,N),R(N,N,N),A(0:3)
INTEGER I3, I2, I1
C
DO 600 I3=2,N-1
DO 600 I2=2,N-1
DO 600 I1=2,N-1
600 R(I1,I2,I3)=V(I1,I2,I3)
> -A(0)*( U(I1, I2, I3 ) )
> -A(1)*( U(I1-1,I2, I3 ) + U(I1+1,I2, I3 )
> + U(I1, I2-1,I3 ) + U(I1, I2+1,I3 )
> + U(I1, I2, I3-1) + U(I1, I2, I3+1) )
> -A(2)*( U(I1-1,I2-1,I3 ) + U(I1+1,I2-1,I3 )
> + U(I1-1,I2+1,I3 ) + U(I1+1,I2+1,I3 )
> + U(I1, I2-1,I3-1) + U(I1, I2+1,I3-1)
> + U(I1, I2-1,I3+1) + U(I1, I2+1,I3+1)
> + U(I1-1,I2, I3-1) + U(I1-1,I2, I3+1)
> + U(I1+1,I2, I3-1) + U(I1+1,I2, I3+1) )
> -A(3)*( U(I1-1,I2-1,I3-1) + U(I1+1,I2-1,I3-1)
> + U(I1-1,I2+1,I3-1) + U(I1+1,I2+1,I3-1)
> + U(I1-1,I2-1,I3+1) + U(I1+1,I2-1,I3+1)
> + U(I1-1,I2+1,I3+1) + U(I1+1,I2+1,I3+1) )
C
RETURN
END
! we want to check that predictive commoning did something on the
! vectorized loop, which means we have to have exactly 13 vector
! additions.
! { dg-final { scan-tree-dump-times "vect_var\[^\\n\]*\\+ " 13 "optimized" } }
! { dg-final { cleanup-tree-dump "vect" } }
! { dg-final { cleanup-tree-dump "optimized" } }
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