re PR middle-end/81931 (r251260 breaks many tests on powerpc64)

	PR middle-end/81931
	* tree-ssanames.c (get_nonzero_bits): Use element_precision
	instead of TYPE_PRECISION.

From-SVN: r251328

gcc/ChangeLog

+2017-08-24  Aldy Hernandez  <aldyh@redhat.com>
+
+	PR middle-end/81931
+	* tree-ssanames.c (get_nonzero_bits): Use element_precision
+	instead of TYPE_PRECISION.
+
 2017-08-24  Richard Sandiford  <richard.sandiford@linaro.org>
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>

gcc/tree-ssanames.c

@@ -470,7 +470,9 @@ get_nonzero_bits (const_tree name)
   if (TREE_CODE (name) == INTEGER_CST)
     return name;
 
-  unsigned int precision = TYPE_PRECISION (TREE_TYPE (name));
+  /* Use element_precision instead of TYPE_PRECISION so complex and
+     vector types get a non-zero precision.  */
+  unsigned int precision = element_precision (TREE_TYPE (name));
   if (POINTER_TYPE_P (TREE_TYPE (name)))
     {
       struct ptr_info_def *pi = SSA_NAME_PTR_INFO (name);