[PATCH] Fix PR66419

[Richard Biener <rguenther@suse.de>]

This fixes PR66419.

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

Richard.

2015-06-08  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/66419
	* tree-vect-slp.c (vect_supported_load_permutation_p): Properly
	consider GROUP_GAP when detecting a perfect subchain.

	* gcc.dg/vect/bb-slp-37.c: New testcase.

Index: gcc/tree-vect-slp.c
===================================================================
--- gcc/tree-vect-slp.c	(revision 224221)
+++ gcc/tree-vect-slp.c	(working copy)
@@ -1444,7 +1459,9 @@ vect_supported_load_permutation_p (slp_i
           next_load = NULL;
           FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (node), j, load)
             {
-              if (j != 0 && next_load != load)
+              if (j != 0
+		  && (next_load != load
+		      || GROUP_GAP (vinfo_for_stmt (load)) != 0))
 		{
 		  subchain_p = false;
 		  break;
Index: gcc/testsuite/gcc.dg/vect/bb-slp-37.c
===================================================================
--- gcc/testsuite/gcc.dg/vect/bb-slp-37.c	(revision 0)
+++ gcc/testsuite/gcc.dg/vect/bb-slp-37.c	(working copy)
@@ -0,0 +1,32 @@
+/* { dg-require-effective-target vect_int } */
+
+#include "tree-vect.h"
+
+extern void abort (void);
+
+int a[16];
+int b[4];
+
+void __attribute__((noinline))
+foo (void)
+{
+  b[0] = a[0];
+  b[1] = a[4];
+  b[2] = a[8];
+  b[3] = a[12];
+}
+
+int main()
+{
+  int i;
+  check_vect ();
+  for (i = 0; i < 16; ++i)
+    {
+      a[i] = i;
+      __asm__ volatile ("");
+    }
+  foo ();
+  if (b[0] != 0 || b[1] != 4 || b[2] != 8 || b[3] != 12)
+    abort ();
+  return 0;
+}