* invoke.texi (Wsuggest-attribute=cold): Document.
	* common.opt (Wsuggest-attribute=cold): New
	* ipa-pure-const.c (warn_function_cold): New function.
	* predict.c (compute_function_frequency): Use it.
	* predict.h (warn_function_cold): Declare.

	* gcc.dg/cold-1.c: New testcase.

From-SVN: r253513