[PATCH] Fix PR65965

[Richard Biener <rguenther@suse.de>]

We don't support vectorizing group stores with gaps - so the natural
thing is to just split groups at such boundaries which enables
more BB vectorization (and likely loop vectorization as well, though
that would be some weird cases I suspect).

Bootstrap and regtest running on x86_64-unknown-linux-gnu.

Richard.

2015-05-04  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/65965
	* tree-vect-data-refs.c (vect_analyze_data_ref_accesses): Split
	store groups at gaps.

	* gcc.dg/vect/bb-slp-33.c: New testcase.

Index: gcc/tree-vect-data-refs.c
===================================================================
--- gcc/tree-vect-data-refs.c	(revision 222758)
+++ gcc/tree-vect-data-refs.c	(working copy)
@@ -2602,6 +2602,15 @@ vect_analyze_data_ref_accesses (loop_vec
 	  if ((init_b - init_a) % type_size_a != 0)
 	    break;
 
+	  /* 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)
+	      && (((unsigned HOST_WIDE_INT)init_b
+		  - TREE_INT_CST_LOW (DR_INIT (datarefs_copy[i-1])))
+		  != type_size_a))
+	    break;
+
 	  /* The step (if not zero) is greater than the difference between
 	     data-refs' inits.  This splits groups into suitable sizes.  */
 	  HOST_WIDE_INT step = tree_to_shwi (DR_STEP (dra));
Index: gcc/testsuite/gcc.dg/vect/bb-slp-33.c
===================================================================
--- gcc/testsuite/gcc.dg/vect/bb-slp-33.c	(revision 0)
+++ gcc/testsuite/gcc.dg/vect/bb-slp-33.c	(working copy)
@@ -0,0 +1,49 @@
+/* { dg-require-effective-target vect_int } */
+
+#include "tree-vect.h"
+
+extern void abort (void);
+
+void __attribute__((noinline,noclone))
+test(int *__restrict__ a, int *__restrict__ b)
+{
+  a[0] = b[0];
+  a[1] = b[1];
+  a[2] = b[2];
+  a[3] = b[3];
+  a[5] = 0;
+  a[6] = 0;
+  a[7] = 0;
+  a[8] = 0;
+}
+
+int main()
+{
+  int a[9];
+  int b[4];
+  b[0] = 1;
+  __asm__ volatile ("");
+  b[1] = 2;
+  __asm__ volatile ("");
+  b[2] = 3;
+  __asm__ volatile ("");
+  b[3] = 4;
+  __asm__ volatile ("");
+  a[4] = 7;
+  check_vect ();
+  test(a, b);
+  if (a[0] != 1
+      || a[1] != 2
+      || a[2] != 3
+      || a[3] != 4
+      || a[4] != 7
+      || a[5] != 0
+      || a[6] != 0
+      || a[7] != 0
+      || a[8] != 0)
+    abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "slp2" { target { vect_element_align || vect_hw_misalign } } } } */
+/* { dg-final { cleanup-tree-dump "slp2" } } */