Re: Lua versus Ravi versus Luajit - another perf test

[Dibyendu Majumdar <mobile@...>]

On 9 March 2015 at 00:00, Ahmed Charles <acharles@outlook.com> wrote:
>> I think more optimization is possible though. For instance - could I
>> avoid setting the types if the compiler knows they are
>> integer/floating? I thought I could but I found an issue.
>> Types can be preset for locals so those are fine.
>> But when expressions are evaluated using temporary registers then if
>> the type is not set what happens is that any operation that uses the
>> temporary value gets the wrong type. Perhaps the compiler could be
>> clever enough to set the type at the end of the expression evaluation
>> rather than at every step. I will look into this more at some point.
>
> Wouldn't the solution to this be to have typed temporaries?
>

Well that is correct but then that is the performance issue - because
I have to set the type on every temporary which means an extra store.

For example:

local i: int = 5+6+7*3

Imagine there is no constant folding and that temporaries are created
for each constant. Then I need to set the type of each temporary for
eventually the right type to be set on the local i.

But the point I was making is that the compiler knows that the type of
the expression is int - so it only needs to set the type at the time
of assignment - not while evaluating the expression.

Does this make sense?

Regards
Dibyendu