Looks like it disappeared here: http://gcc.gnu.org/ml/gcc-patches/2005-01/msg00613.html
I think the list of i386 builtin functions is now out of date in the documentation.
The following differences now exist between the documentation and the current 4.1 x86 code.
I do not know whether all of the changes were intentional.
Documented, but doesn't exist:
__builtin_ia32_cmpnlts __builtin_ia32_loadaps __builtin_ia32_loadddup __builtin_ia32_loadsss ** __builtin_ia32_movddup __builtin_ia32_pextrw __builtin_ia32_pfrsqrtit1 __builtin_ia32_pinsrw __builtin_ia32_storeaps __builtin_ia32_storess
** the docs for loadss have a typo as noted by PR target/20049
While the following exist without being documented:
__builtin_ia32_addpd __builtin_ia32_addsd __builtin_ia32_andnpd __builtin_ia32_andpd __builtin_ia32_clflush __builtin_ia32_cmpeqpd __builtin_ia32_cmpeqsd __builtin_ia32_cmpgepd __builtin_ia32_cmpgtpd __builtin_ia32_cmplepd __builtin_ia32_cmplesd __builtin_ia32_cmpltpd __builtin_ia32_cmpltsd __builtin_ia32_cmpneqpd __builtin_ia32_cmpneqsd __builtin_ia32_cmpngepd __builtin_ia32_cmpngess __builtin_ia32_cmpngtpd __builtin_ia32_cmpngtss __builtin_ia32_cmpnlepd __builtin_ia32_cmpnlesd __builtin_ia32_cmpnltpd __builtin_ia32_cmpnltsd __builtin_ia32_cmpnltss __builtin_ia32_cmpordpd __builtin_ia32_cmpordsd __builtin_ia32_cmpunordpd __builtin_ia32_cmpunordsd __builtin_ia32_comisdeq __builtin_ia32_comisdge __builtin_ia32_comisdgt __builtin_ia32_comisdle __builtin_ia32_comisdlt __builtin_ia32_comisdneq __builtin_ia32_cvtdq2pd __builtin_ia32_cvtdq2ps __builtin_ia32_cvtpd2dq __builtin_ia32_cvtpd2pi __builtin_ia32_cvtpd2ps __builtin_ia32_cvtpi2pd __builtin_ia32_cvtps2dq __builtin_ia32_cvtps2pd __builtin_ia32_cvtsd2si __builtin_ia32_cvtsd2si64 __builtin_ia32_cvtsd2ss __builtin_ia32_cvtsi2sd __builtin_ia32_cvtsi642sd __builtin_ia32_cvtsi642ss __builtin_ia32_cvtss2sd __builtin_ia32_cvtss2si64 __builtin_ia32_cvttpd2dq __builtin_ia32_cvttpd2pi __builtin_ia32_cvttps2dq __builtin_ia32_cvttsd2si __builtin_ia32_cvttsd2si64 __builtin_ia32_cvttss2si64 __builtin_ia32_divpd __builtin_ia32_divsd __builtin_ia32_emms __builtin_ia32_ldmxcsr __builtin_ia32_lfence __builtin_ia32_loaddqu __builtin_ia32_loadhpd __builtin_ia32_loadlpd __builtin_ia32_loadupd __builtin_ia32_maskmovdqu __builtin_ia32_maxpd __builtin_ia32_maxsd __builtin_ia32_mfence __builtin_ia32_minpd __builtin_ia32_minsd __builtin_ia32_movmskpd __builtin_ia32_movntdq __builtin_ia32_movnti __builtin_ia32_movntpd __builtin_ia32_movsd __builtin_ia32_mulpd __builtin_ia32_mulsd __builtin_ia32_orpd __builtin_ia32_packssdw128 __builtin_ia32_packsswb128 __builtin_ia32_packuswb128 __builtin_ia32_paddb128 __builtin_ia32_paddd128 __builtin_ia32_paddq __builtin_ia32_paddq128 __builtin_ia32_paddsb128 __builtin_ia32_paddsw128 __builtin_ia32_paddusb128 __builtin_ia32_paddusw128 __builtin_ia32_paddw128 __builtin_ia32_pand128 __builtin_ia32_pandn128 __builtin_ia32_pavgb128 __builtin_ia32_pavgw128 __builtin_ia32_pcmpeqb128 __builtin_ia32_pcmpeqd128 __builtin_ia32_pcmpeqw128 __builtin_ia32_pcmpgtb128 __builtin_ia32_pcmpgtd128 __builtin_ia32_pcmpgtw128 __builtin_ia32_pfrsqit1 __builtin_ia32_pmaddwd __builtin_ia32_pmaddwd128 __builtin_ia32_pmaxsw128 __builtin_ia32_pmaxub128 __builtin_ia32_pminsw128 __builtin_ia32_pminub128 __builtin_ia32_pmovmskb128 __builtin_ia32_pmulhuw128 __builtin_ia32_pmulhw128 __builtin_ia32_pmullw128 __builtin_ia32_pmuludq __builtin_ia32_pmuludq128 __builtin_ia32_por128 __builtin_ia32_psadbw128 __builtin_ia32_pshufd __builtin_ia32_pshufhw __builtin_ia32_pshuflw __builtin_ia32_pshufw __builtin_ia32_pslld __builtin_ia32_pslld128 __builtin_ia32_pslldi128 __builtin_ia32_pslldqi128 __builtin_ia32_psllq __builtin_ia32_psllq128 __builtin_ia32_psllqi128 __builtin_ia32_psllw __builtin_ia32_psllw128 __builtin_ia32_psllwi128 __builtin_ia32_psrad __builtin_ia32_psrad128 __builtin_ia32_psradi128 __builtin_ia32_psraw __builtin_ia32_psraw128 __builtin_ia32_psrawi128 __builtin_ia32_psrld __builtin_ia32_psrld128 __builtin_ia32_psrldi128 __builtin_ia32_psrldqi128 __builtin_ia32_psrlq __builtin_ia32_psrlq128 __builtin_ia32_psrlqi128 __builtin_ia32_psrlw __builtin_ia32_psrlw128 __builtin_ia32_psrlwi128 __builtin_ia32_psubb128 __builtin_ia32_psubd128 __builtin_ia32_psubq __builtin_ia32_psubq128 __builtin_ia32_psubsb128 __builtin_ia32_psubsw128 __builtin_ia32_psubusb128 __builtin_ia32_psubusw128 __builtin_ia32_psubw128 __builtin_ia32_punpckhbw128 __builtin_ia32_punpckhdq128 __builtin_ia32_punpckhqdq128 __builtin_ia32_punpckhwd128 __builtin_ia32_punpcklbw128 __builtin_ia32_punpckldq128 __builtin_ia32_punpcklqdq128 __builtin_ia32_punpcklwd128 __builtin_ia32_pxor128 __builtin_ia32_shufpd __builtin_ia32_sqrtpd __builtin_ia32_sqrtsd __builtin_ia32_stmxcsr __builtin_ia32_storedqu __builtin_ia32_storeupd __builtin_ia32_subpd __builtin_ia32_subsd __builtin_ia32_ucomisdeq __builtin_ia32_ucomisdge __builtin_ia32_ucomisdgt __builtin_ia32_ucomisdle __builtin_ia32_ucomisdlt __builtin_ia32_ucomisdneq __builtin_ia32_unpckhpd __builtin_ia32_unpcklpd __builtin_ia32_vec_ext_v2df __builtin_ia32_vec_ext_v2di __builtin_ia32_vec_ext_v2si __builtin_ia32_vec_ext_v4hi __builtin_ia32_vec_ext_v4sf __builtin_ia32_vec_ext_v4si __builtin_ia32_vec_ext_v8hi __builtin_ia32_vec_init_v2si __builtin_ia32_vec_init_v4hi __builtin_ia32_vec_init_v8qi __builtin_ia32_vec_set_v4hi __builtin_ia32_vec_set_v8hi __builtin_ia32_xorpd
