gcc/
	PR c/30013
	* config/dfp-bit.c: Don't skip TFmode conversions; move strto*
	declarations to top.
	(DFP_TO_BFP): Use for either XFmode or TFmode.
	(BFP_TO_DFP): Use for either XFmode or TFmode; always use cast
	of BFP_VIA_TYPE.
	* config/dfp-bit.h: Include float.h.
	(LONG_DOUBLE_HAS_XF_MODE, LONG_DOUBLE_HAS_TF_MODE): Define if long
	double is one of these modes, rather than using LIBGCC_HAS_*F_MODE
	which doesn't mean the same thing.
	(BFP_KIND): Use 4 to mean TFmode.
	(BFP_FMT): Specify the number of decimal digits based on the
	number of mantissa digits.
	(BFP_VIA_TYPE): Binary float type to use as cast for sprintf.
	(BFP_TO_DFP, DFP_TO_BFP): Define names for TFmode variants.
	(STR_TO_BFP): Use strtold for XFmode or TFmode.
	(TFtype): Define if TFmode is supported.
	* doc/libgcc.texi (Decimal float library routines): Document
	TF conversion functions.

gcc/testsuite/
	* gcc.dg/dfp/convert-bfp.c: Replace SKIP_LONG_DOUBLE with runtime
	checks for size of long double.
	* gcc.dg/dfp/convert.h: New file.
	* gcc.dg/dfp/convert-bfp-2.c: New test.
	* gcc.dg/dfp/convert-bfp-3.c: Ditto.
	* gcc.dg/dfp/convert-bfp-4.c: Ditto.
	* gcc.dg/dfp/convert-bfp-5.c: Ditto.
	* gcc.dg/dfp/convert-bfp-6.c: Ditto.
	* gcc.dg/dfp/convert-bfp-7.c: Ditto.
	* gcc.dg/dfp/convert-bfp-8.c: Ditto.
	* gcc.dg/dfp/convert-bfp-9.c: Ditto.
	* gcc.dg/dfp/convert-bfp-10.c: Ditto.
	* gcc.dg/dfp/convert-bfp-11.c: Ditto.

From-SVN: r128361