re PR tree-optimization/83232 (fma3d spec2000 regression on zen with -Ofast…

re PR tree-optimization/83232 (fma3d spec2000 regression on zen with -Ofast (generic tuning) after r255268 by missed SLP oppurtunity)

2017-12-01  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/83232
	* tree-vect-data-refs.c (vect_analyze_data_ref_accesses): Fix
	detection of same access. Instead of breaking the group here
	do not consider the duplicate.  Add comment explaining real fix.

	* gfortran.dg/vect/pr83232.f90: New testcase.

From-SVN: r255307

gcc/ChangeLog

+2017-12-01  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/83232
+	* tree-vect-data-refs.c (vect_analyze_data_ref_accesses): Fix
+	detection of same access. Instead of breaking the group here
+	do not consider the duplicate.  Add comment explaining real fix.
+
 2017-12-01  Jonathan Wakely  <jwakely@redhat.com>
 
 	* doc/md.texi (Insn Splitting): Fix "central flowgraph" typo.

gcc/testsuite/ChangeLog

+2017-12-01  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/83232
+	* gfortran.dg/vect/pr83232.f90: New testcase.
+
 2017-12-01  Sudakshina Das  <sudi.das@arm.com>
 
 	* gcc.target/arm/armv8_2-fp16-move-2.c: New test.

gcc/testsuite/gfortran.dg/vect/pr83232.f90

+! { dg-do compile }
+! { dg-require-effective-target vect_double }
+! { dg-additional-options "-funroll-loops --param vect-max-peeling-for-alignment=0 -fdump-tree-slp-details" }
+
+      SUBROUTINE MATERIAL_41_INTEGRATION ( STRESS,YLDC,EFPS,                   &
+     &  DTnext,Dxx,Dyy,Dzz,Dxy,Dxz,Dyz,MatID,P1,P3 )
+      REAL(KIND(0D0)), INTENT(INOUT) :: STRESS(6)
+      REAL(KIND(0D0)), INTENT(IN)    :: DTnext
+      REAL(KIND(0D0)), INTENT(IN)    :: Dxx,Dyy,Dzz,Dxy,Dxz,Dyz
+      REAL(KIND(0D0)) :: Einc(6)
+      REAL(KIND(0D0)) :: P1,P3
+
+      Einc(1) = DTnext * Dxx ! (1)
+      Einc(2) = DTnext * Dyy
+      Einc(3) = DTnext * Dzz
+      Einc(4) = DTnext * Dxy
+      Einc(5) = DTnext * Dxz
+      Einc(6) = DTnext * Dyz
+      DO i = 1,6
+        STRESS(i) = STRESS(i) + P3*Einc(i)
+      ENDDO
+      STRESS(1) = STRESS(1) + (DTnext * P1 * (Dxx+Dyy+Dzz)) ! (2)
+      STRESS(2) = STRESS(2) + (DTnext * P1 * (Dxx+Dyy+Dzz))
+      STRESS(3) = 0.0
+      Einc(5) = 0.0  ! (3)
+      Einc(6) = 0.0
+      call foo (Einc)
+      END SUBROUTINE
+
+! We should vectorize (1) and (2)
+! { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "slp1" } }
+! We fail to vectorize at (3), this can be fixed in the future
+! { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 3 "slp1" { xfail *-*-* } } }

gcc/tree-vect-data-refs.c

@@ -2841,10 +2841,6 @@ vect_analyze_data_ref_accesses (vec_info *vinfo)
 	  if (data_ref_compare_tree (DR_STEP (dra), DR_STEP (drb)) != 0)
 	    break;
 
-	  /* Do not place the same access in the interleaving chain twice.  */
-	  if (tree_int_cst_compare (DR_INIT (dra), DR_INIT (drb)) == 0)
-	    break;
-
 	  /* Check the types are compatible.
 	     ???  We don't distinguish this during sorting.  */
 	  if (!types_compatible_p (TREE_TYPE (DR_REF (dra)),
@@ -2854,7 +2850,25 @@ vect_analyze_data_ref_accesses (vec_info *vinfo)
 	  /* Sorting has ensured that DR_INIT (dra) <= DR_INIT (drb).  */
 	  HOST_WIDE_INT init_a = TREE_INT_CST_LOW (DR_INIT (dra));
 	  HOST_WIDE_INT init_b = TREE_INT_CST_LOW (DR_INIT (drb));
-	  gcc_assert (init_a <= init_b);
+	  HOST_WIDE_INT init_prev
+	    = TREE_INT_CST_LOW (DR_INIT (datarefs_copy[i-1]));
+	  gcc_assert (init_a <= init_b
+		      && init_a <= init_prev
+		      && init_prev <= init_b);
+
+	  /* Do not place the same access in the interleaving chain twice.  */
+	  if (init_b == init_prev)
+	    {
+	      gcc_assert (gimple_uid (DR_STMT (datarefs_copy[i-1]))
+			  < gimple_uid (DR_STMT (drb)));
+	      /* ???  For now we simply "drop" the later reference which is
+	         otherwise the same rather than finishing off this group.
+		 In the end we'd want to re-process duplicates forming
+		 multiple groups from the refs, likely by just collecting
+		 all candidates (including duplicates and split points
+		 below) in a vector and then process them together.  */
+	      continue;
+	    }
 
 	  /* If init_b == init_a + the size of the type * k, we have an
 	     interleaving, and DRA is accessed before DRB.  */
@@ -2866,10 +2880,7 @@ vect_analyze_data_ref_accesses (vec_info *vinfo)
 	  /* If we have a store, the accesses are adjacent.  This splits
 	     groups into chunks we support (we don't support vectorization
 	     of stores with gaps).  */
-	  if (!DR_IS_READ (dra)
-	      && (init_b - (HOST_WIDE_INT) TREE_INT_CST_LOW
-					     (DR_INIT (datarefs_copy[i-1]))
-		  != type_size_a))
+	  if (!DR_IS_READ (dra) && init_b - init_prev != type_size_a)
 	    break;
 
 	  /* If the step (if not zero or non-constant) is greater than the