re PR tree-optimization/87974 (ICE in vect_get_vec_def_for_stmt_copy)

2018-11-14  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/87974
	* tree-vect-loop.c (vectorizable_reduction): When computing
	the vectorized reduction PHI vector type ignore constant
	and external defs.

	* g++.dg/opt/pr87974.C: New testcase.

From-SVN: r266099

gcc/ChangeLog

+2018-11-14  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/87974
+	* tree-vect-loop.c (vectorizable_reduction): When computing
+	the vectorized reduction PHI vector type ignore constant
+	and external defs.
+
 2018-11-14  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/87977

gcc/testsuite/ChangeLog

+2018-11-14  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/87974
+	* g++.dg/opt/pr87974.C: New testcase.
+
 2018-11-14  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/87977

gcc/testsuite/g++.dg/opt/pr87974.C

+// { dg-do compile { target c++11 } }
+// { dg-options "-O3" }
+
+struct h {
+    typedef int &c;
+};
+class i {
+    struct j {
+	using c = int *;
+    };
+    using as = j::c;
+};
+template <typename> class k {
+public:
+    using as = i::as;
+    h::c operator[](long l) {
+	k<int[]>::as d = 0;
+	return d[l];
+    }
+};
+class : public k<int[]> { } a;
+long c, f;
+void m()
+{
+  for (long b; b <= 6; b++)
+    for (long g; g < b; g++) {
+	unsigned long e = g;
+	c = 0;
+	for (; c < b; c++)
+	  f = e >>= 1;
+	a[g] = f;
+    }
+}

gcc/tree-vect-loop.c

@@ -6066,13 +6066,17 @@ vectorizable_reduction (stmt_vec_info stmt_info, gimple_stmt_iterator *gsi,
 	return true;
 
       gassign *reduc_stmt = as_a <gassign *> (reduc_stmt_info->stmt);
+      code = gimple_assign_rhs_code (reduc_stmt);
       for (unsigned k = 1; k < gimple_num_ops (reduc_stmt); ++k)
 	{
 	  tree op = gimple_op (reduc_stmt, k);
 	  if (op == phi_result)
 	    continue;
-	  if (k == 1
-	      && gimple_assign_rhs_code (reduc_stmt) == COND_EXPR)
+	  if (k == 1 && code == COND_EXPR)
+	    continue;
+	  bool is_simple_use = vect_is_simple_use (op, loop_vinfo, &dt);
+	  gcc_assert (is_simple_use);
+	  if (dt == vect_constant_def || dt == vect_external_def)
 	    continue;
 	  if (!vectype_in
 	      || (GET_MODE_SIZE (SCALAR_TYPE_MODE (TREE_TYPE (vectype_in)))