https://issues.dlang.org/show_bug.cgi?id=15873
--- Comment #3 from Walter Bright <bugzi...@digitalmars.com> --- DMD predefines "D_SIMD" for: 1. all 64 bit code generation 2. OSX 32 bit code generation and does generate SIMD instructions for those platforms. DMD does not have compiler switches to select SIMD levels. --