The Cannonlake "CNL" processor list was quietly added to Clang over the weekend along with a few remaining Skylake "SKL" processors plus some extensions now to be exposed when targeting Skylake.
The commit by Intel's Elena Demikhovsky appears to confirm that all Cannonlake CPUs will have AVX-512 support (abx512ifma and avx512vbmi) along with the SHA Extensions and UMIP. The AVX-512 IFMA and VBMI support is more than what's found in some Skylake server CPUs with just avx512f, avx512cd, avx512dq, avx512bw, and avx512vl. But it's great to see all of the Cannonlake CPUs too will receive AVX-512 and just not the high-end server processors.
For targeting Cannonlake is the cannonlake target in Clang for Skylake are the skylake, skx, and skylake-avx512 options.
More details via this Sunday morning commit. Cannonlake processors will be shipping in 2017 as the successor to this year's forthcoming Kabylake CPUs.