[LLVMdev] RFC - Improvements to PGO profile support

[Chandler Carruth]

On Tue, Mar 24, 2015 at 1:08 PM, Xinliang David Li <xinliangli at gmail.com>
wrote:

> Example. Assuming the cap is 'C'
>
> void bar()
> {
>     // ENTRY count is 4*C, after capping it becomes 'C'
>     ...
> }
>
> void test()
> {
>   // BB1:   count(BB1) = C
>   bar();
>
>   // BB2:   count(BB2) = C
>   bar();
>
> }
>
> void test2()
> {
>   // BB3:   count(BB3) = C
>   bar();
>
>   // BB4:   count(BB4) = C
>   bar();
> }
>
> What would inliner see here ? When it sees callsite1 -- it might mistaken
> that is the only dominating callsite to 'bar'.
>

I don't understand, why would it assume this?

I was suggesting that each function would need to be associated with some
global weight, and the global weight ration between test and bar should
provide the needed information here?
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