[Issue 13381] One case of array literal that can be stack-allocated

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13381

--- Comment #5 from yebblies <yebblies at gmail.com> ---
(In reply to bearophile_hugs from comment #4)
> (In reply to yebblies from comment #3)
> 
> > For this case, and similar cases, the compiler can simply type the array
> > literal as a static array, because it knows that == can't escape any
> > references.  It already does something like this for indexing array literals.
> 
> I see. I have suggested a rewrite like this:
> 
> if (a.length == 2 && a[0] == 1 && a[1] == 2) {}
> 
> Because most array literals used for equality or comparison are short or
> very short, so calling == or < on few single items is much more efficient
> than calling a runtime function that works on whole arrays.

Ideally the optimizer would do this by itself, once the literal is
stack-allocated.  I suspect it already does in some cases for gdc/ldc.

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