i386.md (dummy_extendsfdf2): Support SSE2

i386.md (dummy_extendsfdf2): Support SSE2

	* i386.md (dummy_extendsfdf2): Support SSE2
	(extendsfdf2): Enable if 80387 or SSE2.
	(extendsfdf2_1): Support SSE2. Disable if SSE2 is avialble
	and no MIX_I387_SSE2
	(extendsfdf2_1_sse_only): New pattern.
	(truncdfsf2): Enable if SSE2 or 80387; Always use SSE only version
	of SSE.
	(truncdfsf2_1): Support SSE.
	(truncdfsf2_2): Support SSE.
	(truncdfsf2_2_1_sse): New pattern.
	(fixtruncsfsi2): Always use SSE if available.
	(fix_truncsfsi_sse): New pattern.
	(fix_truncdfsi_sse): New pattern.
	(floatsis?f2): Support SSE.
	(floatsidf2_i387): New pattern.
	(floatsidf2_sse): Likewise.

From-SVN: r39634