target.def (min_arithmetic_precision): New hook.

target.def (min_arithmetic_precision): New hook.

	* target.def (min_arithmetic_precision): New hook.
	* doc/tm.texi.in (Misc): Add TARGET_MIN_ARITHMETIC_PRECISION.
	* doc/tm.texi: Regenerate.
	* internal-fn.c (expand_arith_overflow): Adjust handling of target
	dependent support by means of TARGET_MIN_ARITHMETIC_PRECISION.
	* targhooks.c (default_min_arithmetic_precision): New function.
	* targhooks.h (default_min_arithmetic_precision): Declare.
	* config/sparc/sparc.c (TARGET_MIN_ARITHMETIC_PRECISION): Define.
	(sparc_min_arithmetic_precision): New function.

From-SVN: r241665