Eliding of slice range checking

[Kagamin]

On Wednesday, 23 October 2019 at 11:20:59 UTC, Per Nordlöw wrote:
> Does DMD/LDC avoid range-checking in slice-expressions such as 
> the one in my array-overload of `startsWith` defined as
>
> bool startsWith(T)(scope const(T)[] haystack,
>                    scope const(T)[] needle)
> {
>     if (haystack.length >= needle.length)
>     {
>         return haystack[0 .. needle.length] == needle; // is 
> slice range checking avoid here?
>     }
>     return false;
> }

LDC is good at optimizing simple patterns, the only pitfall I 
know is 
https://forum.dlang.org/post/eoftnwkannqmubhjotat@forum.dlang.org