d: Refactor matching and lowering of intrinsic functions.

d: Refactor matching and lowering of intrinsic functions.

Intrinsics are now matched explicitly, rather than through a common
alias where there are multiple overrides for a common intrinsic.
Where there is a corresponding DECL_FUNCTION_CODE, that is now stored in
the D intrinsic array.  All run-time std.math intrinsics have been
removed, as the library implementation already forwards to core.math.

gcc/d/ChangeLog:

	* d-tree.h (DEF_D_INTRINSIC): Rename second argument from A to B.
	* intrinsics.cc (intrinsic_decl): Add built_in field.
	(DEF_D_INTRINSIC): Rename second argument from ALIAS to BUILTIN.
	(maybe_set_intrinsic): Handle new intrinsic codes.
	(expand_intrinsic_bt): Likewise.
	(expand_intrinsic_checkedint): Likewise.
	(expand_intrinsic_bswap): Remove.
	(expand_intrinsic_sqrt): Remove.
	(maybe_expand_intrinsic): Group together intrinsic cases that map
	directly to gcc built-ins.
	* intrinsics.def (DEF_D_BUILTIN): Rename second argument from A to B.
	Update all callers to pass equivalent DECL_FUNCTION_CODE.
	(DEF_CTFE_BUILTIN): Likewise.
	(STD_COS): Remove intrinsic.
	(STD_FABS): Remove intrinsic.
	(STD_LDEXP): Remove intrinsic.
	(STD_RINT): Remove intrinsic.
	(STD_RNDTOL): Remove intrinsic.
	(STD_SIN): Remove intrinsic.
	(STD_SQRTF): Remove intrinsic.
	(STD_SQRT): Remove intrinsic.
	(STD_SQRTL): Remove intrinsic.

gcc/testsuite/ChangeLog:

	* gdc.dg/intrinsics.d: New test.