[LLVMdev] should AlwaysInliner inline this case?

[Liu Xin]

Philip,

I post here because I think AlwaysInliner should inline it. I want to
detect the indirect calls for Inliner, and I want to hear inputs.

let me define indirect call first in my idea. In one single expression, one
function may be subject to bitcast more than one time. we can detect this
situation and treat it as a regular call of last function, is that okay?

thanks,
--lx


On Mon, Jan 5, 2015 at 7:32 AM, Philip Reames <listmail at philipreames.com>
wrote:

> On 01/04/2015 12:04 AM, Liu Xin wrote:
>
>>
>> %294= callfloatbitcast (float(float, float*)* @__gpu_modff to
>> float(float, i64)*)(float%293, i64 %preg.212.addr.0)
>>
>> as you may know, some gpu backends don't support function call. we need
>> to make sure to inline all functions here. however, Inliner can not figure
>> out that this is a valid callsite in this form. actually, it is.  in C
>> words, cast a function and then call should be treat as callsite, right?
>>
>>  Generally, the inliner doesn't do much with indirect calls, but given
> there is no simpler canonical case here, I expect we'll have to.
>
> Its possible we might even want to define this as a direct call. I'm not
> sure what the expectations are with regards to the type of the function
> being called and the type of the callsite.  I suspect a lot of code would
> get confused if getCalledFunction returned __gpu_modff with it's unbitcast
> type.  That's possibly something we should fix though.
>
> We'll want to get other folks input here, but a small patch to the inliner
> to handle this case would seem reasonable to me.
>
> Philip
>
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