-[no-]fastmathUse the fastmath versions for multiply.
Without this flag, only one multiply routine is created which can handle the largest types ever multiplied. This creates smaller programs, at the expence of runtime speed.
When this flag is set, a different multiply routine is generated for each types multiplied. This results in fast code, at the expense of program size. A side effect of this is that any multiplication routine that is only used once is inlined.