builtins.def: Define new builtin functions exp...

builtins.def: Define new builtin functions exp...

	* builtins.def: Define new builtin functions exp, expf, expl,
	log, logf and logl (and their __builtin_* variants).
	* optabs.h (enum optab_index): Add new OTI_exp and OTI_log.
	Define exp_optab and log_optab.
	* optabs.c (init_optans): Initialize exp_optab and log_optab.
	* genopinit.c (optabs): Implement exp_optab and log_optab
	using exp?f2 and log?f2 patterns.
	* builtins.c (expand_builtin_mathfn): Handle BUILT_IN_EXP*
	and BUILT_IN_LOG* using exp_optab and log_optab respectively.
	(expand_builtin): Ignore the new builtins (and all cos and
	sin variants) when not optimizing.  Expand new builtins via
	expand_builtin_mathfn when flag_unsafe_math_optimizations.

	* doc/extend.texi: Document new exp and log builtins.
	* doc/md.texi: Document new exp?f2 and log?f2 patterns
	(and previously undocumented cos?f2 and sin?f2 patterns).

From-SVN: r56010