Allow variable-sized temporary variables in gimplify.c

This is needed to build libgfortran for SVE.  The OpenMP code needs
to create temporary vector variables, and the variables will therefore
be variable-sized for SVE.  Earlier patches made such variables work.

2018-01-12  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* gimplify.c (gimple_add_tmp_var_fn): Allow variables to have a
	poly_uint64 size, rather than requiring an unsigned HOST_WIDE_INT size.
	(gimple_add_tmp_var): Likewise.

From-SVN: r256585

gcc/ChangeLog

+2018-01-12  Richard Sandiford  <richard.sandiford@linaro.org>
+
+	* gimplify.c (gimple_add_tmp_var_fn): Allow variables to have a
+	poly_uint64 size, rather than requiring an unsigned HOST_WIDE_INT size.
+	(gimple_add_tmp_var): Likewise.
+
 2018-01-12  Martin Liska  <mliska@suse.cz>
 
 	* gimple.c (gimple_alloc_counts): Use uint64_t instead of int.

gcc/gimplify.c

@@ -702,7 +702,7 @@ gimple_add_tmp_var_fn (struct function *fn, tree tmp)
   /* Later processing assumes that the object size is constant, which might
      not be true at this point.  Force the use of a constant upper bound in
      this case.  */
-  if (!tree_fits_uhwi_p (DECL_SIZE_UNIT (tmp)))
+  if (!tree_fits_poly_uint64_p (DECL_SIZE_UNIT (tmp)))
     force_constant_size (tmp);
 
   DECL_CONTEXT (tmp) = fn->decl;
@@ -721,7 +721,7 @@ gimple_add_tmp_var (tree tmp)
   /* Later processing assumes that the object size is constant, which might
      not be true at this point.  Force the use of a constant upper bound in
      this case.  */
-  if (!tree_fits_uhwi_p (DECL_SIZE_UNIT (tmp)))
+  if (!tree_fits_poly_uint64_p (DECL_SIZE_UNIT (tmp)))
     force_constant_size (tmp);
 
   DECL_CONTEXT (tmp) = current_function_decl;