The problem in the PR is that some i386 optabs FAIL when
optimising for size rather than speed.  The gimple level generally
needs access to this information before calling the generator,
so this patch adds a new hook to say whether an optab should
be used when optimising for size or speed.  It also has a "both"
option for cases where we want code that is optimised for both
size and speed.

I've passed the optab to the target hook because I think in most
cases that's more useful than the instruction code.  We could pass
both if there's a use for it though.

At the moment the match-and-simplify code doesn't have direct access
to the target block, so for now I've used "both" there.

Tested on x86_64-linux-gnu and powerpc64-linux-gnu.

gcc/
	PR tree-optimization/68432
	* coretypes.h (optimization_type): New enum.
	* doc/tm.texi.in (TARGET_OPTAB_SUPPORTED_P): New hook.
	* doc/tm.texi: Regenerate.
	* target.def (optab_supported_p): New hook.
	* targhooks.h (default_optab_supported_p): Declare.
	* targhooks.c (default_optab_supported_p): New function.
	* predict.h (function_optimization_type): Declare.
	(bb_optimization_type): Likewise.
	* predict.c (function_optimization_type): New function.
	(bb_optimization_type): Likewise.
	* optabs-query.h (convert_optab_handler): Define an overload
	that takes an optimization type.
	(direct_optab_handler): Likewise.
	* optabs-query.c (convert_optab_handler): Likewise.
	(direct_optab_handler): Likewise.
	* internal-fn.h (direct_internal_fn_supported_p): Take an
	optimization_type argument.
	* internal-fn.c (direct_optab_supported_p): Likewise.
	(multi_vector_optab_supported_p): Likewise.
	(direct_internal_fn_supported_p): Likewise.
	* builtins.c (replacement_internal_fn): Update call to
	direct_internal_fn_supported_p.
	* gimple-match-head.c (build_call_internal): Likewise.
	* tree-vect-patterns.c (vect_recog_pow_pattern): Likewise.
	* tree-vect-stmts.c (vectorizable_internal_function): Likewise.
	* tree.c (maybe_build_call_expr_loc): Likewise.
	* config/i386/i386.c (ix86_optab_supported_p): New function.
	(TARGET_OPTAB_SUPPORTED_P): Define.
	* config/i386/i386.md (asinxf2): Remove optimize_insn_for_size_p check.
	(asin<mode>2, acosxf2, acos<mode>2, log1pxf2, log1p<mode>2)
	(expNcorexf3, expxf2, exp<mode>2, exp10xf2, exp10<mode>2, exp2xf2)
	(exp2<mode>2, expm1xf2, expm1<mode>2, ldexpxf3, ldexp<mode>3)
	(scalbxf3, scalb<mode>3, rint<mode>2, round<mode>2)
	(<rounding_insn>xf2, <rounding_insn><mode>2): Likewise.

gcc/testsuite/
	* gcc.target/i386/pr68432-1.c: New test.
	* gcc.target/i386/pr68432-2.c: Likewise.
	* gcc.target/i386/pr68432-3.c: Likewise.

From-SVN: r231161