re PR target/47989 (-mrecip causes 482.sphinx3, 464.h264ref and 481.wrf to miscompare)

re PR target/47989 (-mrecip causes 482.sphinx3, 464.h264ref and 481.wrf to miscompare)

	PR target/47989
	* config/i386/i386.h (RECIP_MASK_DEFAULT): New define.
	* config/i386/i386.op (recip_mask): Initialize with RECIP_MASK_DEFAULT.
	* doc/invoke.texi (ix86 Options, -mrecip): Document that GCC
	implements vectorized single float division and vectorized sqrtf(x)
	with reciprocal sequence with additional Newton-Raphson step with
	-ffast-math.

From-SVN: r180256