There's nowhere to add -mf16c and -mfma that doesn't cause a uinversal build to spew warnings about those settings when it builds arm64. I'd rather not have to add a xcconfig file across every project with an x64 specific setting. So why doesn't the AVX2 setting (-mavx2) also set these flags?
-mhaswell does, and so does -mx86-64-...-v3, but those seem to only be supported by clang-cli on Windows.