re PR tree-optimization/60510 (SLP blocks loop vectorization (with reduction))

2017-07-03  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/60510
	* tree-vect-loop.c (vect_create_epilog_for_reduction): Pass in
	the scalar reduction PHI and use it.
	(vectorizable_reduction): Properly guard the single_defuse_cycle
	path for non-SLP reduction chains where we cannot use it.
	Rework reduc_def/index and vector type deduction.  Rework
	vector operand gathering during reduction op code-gen.
	* tree-vect-slp.c (vect_analyze_slp): For failed SLP reduction
	chains dissolve the chain and leave it to non-SLP reduction
	handling.

	* gfortran.dg/vect/pr60510.f: New testcase.

From-SVN: r249919

gcc/ChangeLog

+2017-07-03  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/60510
+	* tree-vect-loop.c (vect_create_epilog_for_reduction): Pass in
+	the scalar reduction PHI and use it.
+	(vectorizable_reduction): Properly guard the single_defuse_cycle
+	path for non-SLP reduction chains where we cannot use it.
+	Rework reduc_def/index and vector type deduction.  Rework
+	vector operand gathering during reduction op code-gen.
+	* tree-vect-slp.c (vect_analyze_slp): For failed SLP reduction
+	chains dissolve the chain and leave it to non-SLP reduction
+	handling.
+
 2017-07-03  Richard Sandiford  <richard.sandiford@linaro.org>
 
 	* tree-data-ref.h (dr_alignment): Declare.

gcc/testsuite/ChangeLog

+2017-07-03  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/60510
+	* gfortran.dg/vect/pr60510.f: New testcase.
+
 2017-07-03  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* gcc.target/i386/mvc6.c: Require ifunc support.

gcc/testsuite/gfortran.dg/vect/pr60510.f

+! { dg-do run }
+! { dg-additional-options "-fno-inline -ffast-math" }
+      subroutine foo(a,x,y,n)
+      implicit none
+      integer n,i
+
+      real*8 y(n),x(n),a
+
+      do i=1,n
+         a=a+x(i)*y(i)+x(i)
+      enddo
+
+      return
+      end
+
+      program test
+      real*8 x(1024),y(1024),a
+      do i=1,1024
+        x(i) = i
+        y(i) = i+1
+      enddo
+      call foo(a,x,y,1024)
+      if (a.ne.359488000.0) call abort()
+      end
+! If there's no longer a reduction chain detected this doesn't test what
+! it was supposed to test, vectorizing a reduction chain w/o SLP.
+! { dg-final { scan-tree-dump "reduction chain" "vect" } }
+! We should vectorize the reduction in foo and the induction in test.
+! { dg-final { scan-tree-dump-times "vectorized 1 loops" 2 "vect" } }

gcc/tree-vect-slp.c

@@ -2121,7 +2121,20 @@ vect_analyze_slp (vec_info *vinfo, unsigned max_tree_size)
 	  FOR_EACH_VEC_ELT (loop_vinfo->reduction_chains, i, first_element)
 	    if (! vect_analyze_slp_instance (vinfo, first_element,
 					     max_tree_size))
-	      return false;
+	      {
+		/* Dissolve reduction chain group.  */
+		gimple *next, *stmt = first_element;
+		while (stmt)
+		  {
+		    stmt_vec_info vinfo = vinfo_for_stmt (stmt);
+		    next = GROUP_NEXT_ELEMENT (vinfo);
+		    GROUP_FIRST_ELEMENT (vinfo) = NULL;
+		    GROUP_NEXT_ELEMENT (vinfo) = NULL;
+		    stmt = next;
+		  }
+		STMT_VINFO_DEF_TYPE (vinfo_for_stmt (first_element))
+		  = vect_internal_def;
+	      }
 	}
 
       /* Find SLP sequences starting from groups of reductions.  */