Effect of --multifile on compilation build time

When compiling with --multifile, the compiler might generate code with additional optimizations by compiling across several source files to produce a single object file. These additional cross-source optimizations can increase compilation time.

Conversely, if there is little additional optimization to apply, and only small amounts of code to check for possible optimizations, then using --multifile to generate a single object file instead of several might reduce compilation time as a result of time recovered from creating (opening and closing) multiple object files.