re PR middle-end/56524 (Compiler ICE when compiling with -mips16)

gcc/
	PR middle-end/56524
	* tree.h (tree_optimization_option): Rename target_optabs to optabs.
	Add base_optabs.
	(TREE_OPTIMIZATION_OPTABS): Update after previous field change.
	(TREE_OPTIMIZATION_BASE_OPTABS): New macro.
	(save_optabs_if_changed): Replace with...
	(init_tree_optimization_optabs): ...this.
	* optabs.c (save_optabs_if_changed): Rename to...
	(init_tree_optimization_optabs): ...this.  Take the optimization node
	as argument.  Do nothing if the base optabs are already correct.
	Reuse the existing TREE_OPTIMIZATION_OPTABS memory if we need
	to recompute optabs.
	* function.h (function): Remove optabs field.
	* function.c (invoke_set_current_function_hook): Call
	init_tree_optimization_optabs.  Use the result to initialize
	this_fn_optabs.

gcc/c-family/
	PR middle-end/56524
	* c-common.c (handle_optimize_attribute): Don't call
	save_optabs_if_changed.

gcc/testsuite/
	PR middle-end/56524
	* gcc.target/mips/pr56524.c: New test.

From-SVN: r196570