Changes from Git (git http://labmaster3.local/git/llvm-project.git)
[X86] Use zero vector to extend to 512-bits for strict_fp_to_uint (details)
[X86] Use zero vector to extend to 512-bits for strict_fp_to_uint v2i1->v2f64 on targets with AVX512F, but not AVX512VL. In the worst case, this requires a 128-bit move instruction to implicitly zero the upper bits. In the common case, we should recognize the producing instruction already zeroed the upper bits.