https://sourceware.org/bugzilla/show_bug.cgi?id=18700
--- Comment #4 from lili.cui at intel dot com <lili.cui at intel dot com> --- This is not an issue anymore. I tested these instructions on a machine with AVX512 and they are correct. 0000000000001222 <foo>: 1222: f3 0f 1e fa endbr64 1226: 55 push %rbp 1227: 48 89 e5 mov %rsp,%rbp 122a: 62 f1 f5 18 c2 ca 00 vcmpeqpd {sae},%zmm2,%zmm1,%k1 1231: 62 f1 f5 48 c2 ca 00 vcmpeqpd %zmm2,%zmm1,%k1 1238: 62 f1 f7 18 c2 ca 00 vcmpeqsd {sae},%xmm2,%xmm1,%k1 123f: 62 f1 f7 08 c2 ca 00 vcmpeqsd %xmm2,%xmm1,%k1 1246: 62 f1 f5 38 c2 ca 00 vcmpeqpd {sae},%zmm2,%zmm1,%k1 124d: 5d pop %rbp 124e: c3 ret For "62 f1 f5 38 c2 ca 00 vcmpeqpd {sae},%zmm2,%zmm1,%k1" I think when reg-reg and EVEX.b is 1, vcmpeqpd will ignore EVEX.L'L(I tested them in the foo), and when EVEX.b is 0, EVEX.L'L makes sense. Thanks to Michael for pointing out the inconsistencies in SDM. I checked them one by one in SDM and found that they have all been corrected. Now the logic is clearer. For vcmpeqpd : 1c: 62 f1 f5 18 c2 ca 00 vcmpeqpd {sae},%zmm2,%zmm1,%k1 23: 62 f1 f5 38 c2 ca 00 vcmpeqpd {sae},%zmm2,%zmm1,%k1 2a: 62 f1 f5 58 c2 ca 00 vcmpeqpd {sae},%zmm2,%zmm1,%k1 31: 62 f1 f5 78 c2 ca 00 vcmpeqpd {sae},%zmm2,%zmm1,%k1 I think when reg-reg and EVEX.b is 1, vcmpeqpd will ignore EVEX.L'L(I tested them in the foo), and when EVEX.b is 0, EVEX.L'L makes sense. -- You are receiving this mail because: You are on the CC list for the bug.