RFR 8038418 New tests development for type profiling and speculation

[Pavel Punegov]

Roland,

On Wed, 09 of Apr 2014 11:52:54 Roland Westrelin wrote:
> Hi Pavel,
> 
>> Webrev: http://cr.openjdk.java.net/~iignatyev/ppunegov/8038418/webrev.01/
> 
> As I understand, with that code:
> 
>   67     public Integer run(T obj) {
>   68         if (isReturnType) {
>   69             obj = collectReturnType(obj);
>   70         }
>   71         return inlinee(obj);
>   72     }
> 
> it is expected that the compiler has profiling for incoming parameters to
> run(), return from collectReturnType(), arguments at call to inlinee().
Yep. Most of scenarios try to use all three types of type profiling, and I 
expect that collectReturnType(obj) will give us return profiling data.

> Because, it knowns from the parameter the profiled type of obj, the compiler
> doesn’t use return value profiling or argument profiling. So I don’t think
> the tests exercise arguments/return value profiling. 
But what if the collectReturnType(obj) will change the obj inside the method?
E.g. before it was a TypeHierarchy.B, but became a TypeHierarchy. I thought 
that it should use return type profiling for this case:

   obj = collectReturnType(obj);
   return inlinee(obj);


> One way to test each
> one would be to run with different values of TypeProfileLevel (200, 020,
> 002) or the scenarios/tests would need to be changed so that you can
> pollute parameter profiling + return value profiling but not argument
> profiling etc.
> 
> Also with this:
> 
>   68         if (isReturnType) {
>   69             obj = collectReturnType(obj);
>   70         }
> 
> 
> return value profiling is only valid within the if() so it can’t be used be
> the compiler. Something like this:
but why does compiler not eliminate if() when isReturnType == true and is a 
final field? 

> if (isReturnType) {
>   obj = collectReturnType(obj);
>   return inlinee(obj);
> }
> return inlinee(obj);
> 
> is better.
If it helps, then I'll change test scenarios to have the same code inside the 
if() as in the outside.

-- 
Thanks,
Pavel Punegov