xmmintrin.h (_mm_setzero_ps, [...]): Add __extension__.

xmmintrin.h (_mm_setzero_ps, [...]): Add __extension__.

	* config/i386/xmmintrin.h (_mm_setzero_ps, _mm_set_ss, _mm_set1_ps,
	_mm_set_ps, _mm_setr_ps): Add __extension__.
	* config/i386/emmintrin.h (_mm_set_sd, _mm_set1_pd, _mm_set_pd,
	_mm_setr_pd, _mm_setzero_pd, _mm_set_epi64x, _mm_set_epi64x,
	_mm_set_epi32, _mm_set_epi16, _mm_set_epi8, _mm_setzero_si128):
	Likewise.
	(_mm_clflush): Don't use return in void function.

	* gcc.dg/i386-sse-12.c: New test.

From-SVN: r100439