re PR rtl-optimization/15242 (pessimization of "goto *")

re PR rtl-optimization/15242 (pessimization of "goto *")

	PR optimization/15242
	* params.def (PARAM_MAX_GOTO_DUPLICATION_INSNS): New param.
	* basic-block.h (duplicate_computed_gotos): Add prototype.
	* bb-reorder.c (duplicate_computed_gotos): New function to
	duplicate sufficiently small blocks ending in a computed jump.
	* passes.c (rest_of_compilation): Call duplicate_computed_gotos
	if not optimizing for size.
	* cfgcleanup.c (try_crossjump_bb): If not optimizing for size,
	never do tail merging for blocks ending in a computed jump.
	* doc/invoke.texi: Document the max-goto-duplication-insns param.

From-SVN: r94531