re PR target/54222 ([avr] Implement fixed-point support)

re PR target/54222 ([avr] Implement fixed-point support)

gcc/
	PR target/54222
	* config/avr/builtins.def (DEF_BUILTIN): Add LIBNAME argument.
	Add NULL LIBNAME argument to existing definitions.
	(ABSHR, ABSR, ABSLR, ABSLLR, ABSHK, ABSK, ABSLK, ABSLLK): New.
	* config/avr/avr-c.c (DEF_BUILTIN): Add LIBNAME argument.
	* config/avr/avr.c (DEF_BUILTIN): Same.
	(avr_init_builtins): Pass down LIBNAME to add_builtin_function.
	(avr_expand_builtin): Expand to a vanilla call if a libgcc
	implementation is available (DECL_ASSEMBLER_NAME is set).
	(avr_fold_absfx): New static function.
	(avr_fold_builtin): Use it to handle: AVR_BUILTIN_ABSHR,
	AVR_BUILTIN_ABSR, AVR_BUILTIN_ABSLR, AVR_BUILTIN_ABSLLR,
	AVR_BUILTIN_ABSHK, AVR_BUILTIN_ABSK, AVR_BUILTIN_ABSLK,
	AVR_BUILTIN_ABSLLK.
	* config/avr/stdfix.h (abshr, absr, abslr, absllr)
	(abshk, absk, abslk, absllk): Provide as static inline functions.

gcc/testsuite/
	PR target/54222
	* gcc.target/avr/torture/builtins-3-absfx.c: New test.

From-SVN: r195464