Function core::arch::x86::_mm_cmp_sd

pub unsafe fn _mm_cmp_sd(a: __m128d, b: __m128d, imm8: i32) -> __m128d

This is supported on x86 and target feature avx,sse2 only.

Compare the lower double-precision (64-bit) floating-point element in a and b based on the comparison operand specified by imm8, store the result in the lower element of returned vector, and copy the upper element from a to the upper element of returned vector.

Intel's documentation