The following fixes an oversight in SLP reduction permutation
optimization which will happily delete permutations required for
handling of gaps.
Bootstrapped on x86_64-unknown-linux-gnu, testin in progress.
Richard.
2016-02-22 Richard Biener <rguent...@suse.de>
PR tree-optimization/69882
* tree-vect-slp.c (vect_attempt_slp_rearrange_stmts): Properly
preserve permutations present because of gaps.
(vect_supported_load_permutation_p): Always continue checking
permutations after vect_attempt_slp_rearrange_stmts.
* gfortran.dg/vect/pr69882.f90: New testcase.
Index: gcc/tree-vect-slp.c
===================================================================
*** gcc/tree-vect-slp.c (revision 233598)
--- gcc/tree-vect-slp.c (working copy)
*************** vect_attempt_slp_rearrange_stmts (slp_in
*** 1332,1339 ****
node->load_permutation);
/* We are done, no actual permutations need to be generated. */
FOR_EACH_VEC_ELT (SLP_INSTANCE_LOADS (slp_instn), i, node)
! SLP_TREE_LOAD_PERMUTATION (node).release ();
return true;
}
--- 1332,1350 ----
node->load_permutation);
/* We are done, no actual permutations need to be generated. */
+ unsigned int unrolling_factor = SLP_INSTANCE_UNROLLING_FACTOR (slp_instn);
FOR_EACH_VEC_ELT (SLP_INSTANCE_LOADS (slp_instn), i, node)
! {
! gimple *first_stmt = SLP_TREE_SCALAR_STMTS (node)[0];
! first_stmt = GROUP_FIRST_ELEMENT (vinfo_for_stmt (first_stmt));
! /* But we have to keep those permutations that are required because
! of handling of gaps. */
! if (unrolling_factor == 1
! || (group_size == GROUP_SIZE (vinfo_for_stmt (first_stmt))
! && GROUP_GAP (vinfo_for_stmt (first_stmt)) == 0))
! SLP_TREE_LOAD_PERMUTATION (node).release ();
! }
!
return true;
}
*************** vect_supported_load_permutation_p (slp_i
*** 1381,1392 ****
In reduction chain the order of the loads is not important. */
if (!STMT_VINFO_DATA_REF (vinfo_for_stmt (stmt))
&& !GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt)))
! {
! if (vect_attempt_slp_rearrange_stmts (slp_instn))
! return true;
!
! /* Fallthru to general load permutation handling. */
! }
/* In basic block vectorization we allow any subchain of an interleaving
chain.
--- 1392,1398 ----
In reduction chain the order of the loads is not important. */
if (!STMT_VINFO_DATA_REF (vinfo_for_stmt (stmt))
&& !GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt)))
! vect_attempt_slp_rearrange_stmts (slp_instn);
/* In basic block vectorization we allow any subchain of an interleaving
chain.
Index: gcc/testsuite/gfortran.dg/vect/pr69882.f90
===================================================================
*** gcc/testsuite/gfortran.dg/vect/pr69882.f90 (revision 0)
--- gcc/testsuite/gfortran.dg/vect/pr69882.f90 (working copy)
***************
*** 0 ****
--- 1,41 ----
+ ! { dg-additional-options "-Ofast" }
+ ! { dg-additional-options "-mavx" { target avx_runtime } }
+
+ subroutine foo(a, x)
+ implicit none
+
+ integer, parameter :: XX=4, YY=26
+ integer, intent(in) :: x
+ real *8, intent(in) :: a(XX,YY)
+ real *8 :: c(XX)
+
+ integer i, k
+
+ c = 0
+
+ do k=x,YY
+ do i=1,2
+ c(i) = max(c(i), a(i,k))
+ end do
+ end do
+
+ PRINT *, "c=", c
+
+ IF (c(1) .gt. 0.0) THEN
+ CALL ABORT
+ END IF
+
+ IF (c(2) .gt. 0.0) THEN
+ CALL ABORT
+ END IF
+ end subroutine foo
+
+ PROGRAM MAIN
+ real *8 a(4, 26)
+
+ a = 0
+ a(3,1) = 100.0
+ a(4,1) = 100.0
+
+ CALL FOO(a, 1)
+ END PROGRAM
