On Wednesday, 29 December 2021 at 17:20:59 UTC, max haughton
wrote:
This is handled by the compiler backend. The simplest way it
can do this kind of optimization is by "inlining" the function.
This is done by transplanting the function body into the place
it's used. At this point the compiler simply sees "= 30 + 30"
which it can trivially turn into "= 60" through something
called constant-folding.
The compiler can create new function bodies (like the temp one
you introduce above) but this is a much more niche
optimization. They favour inlining much more aggressively.
I'm tempted to do a YouTube video of a D program being compiled
all the way down the machine code, to show what the compiler
does for you.
I didn't knew that compilers work like that. I thought that it
will treat the values normally like they were values that cannot
get computed at compile time even if you pass them as literals.
That's good to know
