xtensa: report stack usage

This enables options -fstack-usage and -Wstack-usage.

2016-08-26  Max Filippov  <jcmvbkbc@gmail.com>
gcc/
	* config/xtensa/xtensa.c (xtensa_expand_prologue): Update
	current_function_static_stack_size variable with the static
	stack frame size of the current function when
	flag_stack_usage_info is enabled.

From-SVN: r239785

gcc/ChangeLog

+2016-08-26  Max Filippov  <jcmvbkbc@gmail.com>
+
+	* config/xtensa/xtensa.c (xtensa_expand_prologue): Update
+	current_function_static_stack_size variable with the static
+	stack frame size of the current function when
+	flag_stack_usage_info is enabled.
+
 2016-08-26  Nathan Sidwell  <nathan@acm.org>
 
 	* ipa-inline-analysis.c (inline_write_summary): Remove unnecessary

gcc/config/xtensa/xtensa.c

@@ -2678,6 +2678,9 @@ xtensa_expand_prologue (void)
 
   total_size = compute_frame_size (get_frame_size ());
 
+  if (flag_stack_usage_info)
+    current_function_static_stack_size = total_size;
+
   if (TARGET_WINDOWED_ABI)
     {
       if (total_size < (1 << (12+3)))