re PR rtl-optimization/79901 (ICE in prepare_cmp_insn, at optabs.c:3904)

	PR rtl-optimization/79901
	* expr.c (expand_expr_real_2): For vector MIN/MAX, if there is no
	min/max expander, expand it using expand_vec_cond_expr.

From-SVN: r245946

gcc/ChangeLog

 2017-03-07  Jakub Jelinek  <jakub@redhat.com>
 
+	PR rtl-optimization/79901
+	* expr.c (expand_expr_real_2): For vector MIN/MAX, if there is no
+	min/max expander, expand it using expand_vec_cond_expr.
+
 	PR sanitizer/79897
 	* ubsan.c (ubsan_encode_value): Call mark_addressable on the
 	temporary.

gcc/expr.c

@@ -8943,6 +8943,18 @@ expand_expr_real_2 (sepops ops, rtx target, machine_mode tmode,
       if (temp != 0)
 	return temp;
 
+      /* For vector MIN <x, y>, expand it a VEC_COND_EXPR <x <= y, x, y>
+	 and similarly for MAX <x, y>.  */
+      if (VECTOR_TYPE_P (type))
+	{
+	  tree t0 = make_tree (type, op0);
+	  tree t1 = make_tree (type, op1);
+	  tree comparison = build2 (code == MIN_EXPR ? LE_EXPR : GE_EXPR,
+				    type, t0, t1);
+	  return expand_vec_cond_expr (type, comparison, t0, t1,
+				       original_target);
+	}
+
       /* At this point, a MEM target is no longer useful; we will get better
 	 code without it.  */