Restore flow_bb_inside_loop_p tests (PR 86858)

The series to remove vinfo_for_stmt also removed tests of
flow_bb_inside_loop_p if the call was simply testing whether the
statement was in the vectorisation region.  I'd tried to keep calls
that were testing whether the statement was in a particular loop
(inner or outer), but messed up in vect_is_simple_reduction and
removed calls that were actually needed.  This patch restores them.

I double-checked the other removed calls and I think these are
the only ones affected.

2018-08-08  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	PR tree-optimization/86858
	* tree-vect-loop.c (vect_is_simple_reduction): Restore
	flow_bb_inside_loop_p calls.

gcc/testsuite/
	PR tree-optimization/86858
	* gcc.dg/vect/pr86858.c: New test.

From-SVN: r263448

gcc/ChangeLog

 2018-08-09  Richard Sandiford  <richard.sandiford@arm.com>
 
+	PR tree-optimization/86858
+	* tree-vect-loop.c (vect_is_simple_reduction): Restore
+	flow_bb_inside_loop_p calls.
+
+2018-08-09  Richard Sandiford  <richard.sandiford@arm.com>
+
 	PR tree-optimization/86871
 	* tree-vect-stmts.c (vect_transform_stmt): Use gimple_get_lhs
 	instead of gimple_assign_lhs.

gcc/testsuite/ChangeLog

 2018-08-09  Richard Sandiford  <richard.sandiford@arm.com>
 
+	PR tree-optimization/86858
+	* gcc.dg/vect/pr86858.c: New test.
+
+2018-08-09  Richard Sandiford  <richard.sandiford@arm.com>
+
 	PR tree-optimization/86871
 	* gcc.dg/vect/pr86871.c: New test.
 

gcc/testsuite/gcc.dg/vect/pr86858.c

+/* { dg-do compile } */
+
+int a, b, c, d;
+char e(char f, char g) { return f + g; }
+void h() {
+  for (; c; ++c) {
+    d = 0;
+    for (; d != 8; d = e(d, 3)) {
+      a = b && a;
+      b = c;
+    }
+  }
+}

gcc/tree-vect-loop.c

@@ -2922,7 +2922,8 @@ vect_is_simple_reduction (loop_vec_info loop_info, stmt_vec_info phi_info,
     }
 
   stmt_vec_info def_stmt_info = loop_info->lookup_def (loop_arg);
-  if (!def_stmt_info)
+  if (!def_stmt_info
+      || !flow_bb_inside_loop_p (loop, gimple_bb (def_stmt_info->stmt)))
     return NULL;
 
   if (gassign *def_stmt = dyn_cast <gassign *> (def_stmt_info->stmt))
@@ -3161,6 +3162,7 @@ vect_is_simple_reduction (loop_vec_info loop_info, stmt_vec_info phi_info,
       && def2_info->stmt == phi
       && (code == COND_EXPR
 	  || !def1_info
+	  || !flow_bb_inside_loop_p (loop, gimple_bb (def1_info->stmt))
 	  || vect_valid_reduction_input_p (def1_info)))
     {
       if (dump_enabled_p ())
@@ -3172,6 +3174,7 @@ vect_is_simple_reduction (loop_vec_info loop_info, stmt_vec_info phi_info,
       && def1_info->stmt == phi
       && (code == COND_EXPR
 	  || !def2_info
+	  || !flow_bb_inside_loop_p (loop, gimple_bb (def2_info->stmt))
 	  || vect_valid_reduction_input_p (def2_info)))
     {
       if (! nested_in_vect_loop && orig_code != MINUS_EXPR)