Remove the assert in Integer.valueOf()

[Rémi Forax]

On 04/23/2012 07:43 PM, Mario Torre wrote:
> 2012/4/23 Rémi Forax<forax at univ-mlv.fr>:
>
>> The issue is that Hotspot also count the bytecodes related to assert
>> in its inlining heuristic.
>> If the assert is commented, the inlining tree is good.
> [...]
>
>> Given that Integer.valueOf() is a method used very often and that if the
>> inlining fails,
>> the escape analysis will not remove the allocation,
>> I think it's a good idea to comment this assert.
> Hi Rémi,
>
> I'm not sure if it's a good idea or not to remove the assert.
>
> What happens if we replace the assert with a specific check, is it
> still not inlined?
>
> Cheers,
> Mario

Hi Marrio,
if you add a check, you augment the size of the bytecode
and unluckily the Hostspot inlining heuristic is based on the size of 
the bytecode.

I've also forgotten to mention that this assert is useless given the code
the static block of Integer.IntegerCache.

static final int low = -128;
       static final int high;
static {
             // high value may be configured by property
             int h = 127;
             String integerCacheHighPropValue =
                 
sun.misc.VM.getSavedProperty("java.lang.Integer.IntegerCache.high");
             if (integerCacheHighPropValue != null) {
                 int i = parseInt(integerCacheHighPropValue);
                 i = Math.max(i, 127);
                 // Maximum array size is Integer.MAX_VALUE
                 h = Math.min(i, Integer.MAX_VALUE - (-low));
             }
             high = h;

             ...
         }

cheers,
Rémi