RFR(S): 8063086: Math.pow yields different results upon repeated calls

[Roland Westrelin]

Thanks for the re-review, Vladimir.

Roland.

> On Jan 8, 2015, at 5:58 PM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
> 
> Okay.
> 
> Thanks,
> Vladimir
> 
> On 1/8/15 1:26 AM, Roland Westrelin wrote:
>> When trying to push this through jprt I had an assert failure due to an unreachable address. Here is a new webrev:
>> 
>> http://cr.openjdk.java.net/~roland/8063086/webrev.01/
>> 
>> with the following change:
>> 
>> --- a/src/cpu/x86/vm/macroAssembler_x86.cpp
>> +++ b/src/cpu/x86/vm/macroAssembler_x86.cpp
>> @@ -3189,7 +3189,9 @@
>>      static double two = 2.0;
>>      ExternalAddress two_addr((address)&two);
>> 
>> -    fld_d(two_addr);            // Stack: 2 X Y
>> +    // constant maybe too far on 64 bit
>> +    lea(tmp2, two_addr);
>> +    fld_d(Address(tmp2, 0));    // Stack: 2 X Y
>>      fcmp(tmp, 2, true, false);  // Stack: X Y
>>      jcc(Assembler::parity, y_not_2);
>>      jcc(Assembler::notEqual, y_not_2);
>> 
>> Roland.
>> 
>>> On Jan 7, 2015, at 2:20 PM, Roland Westrelin <roland.westrelin at oracle.com> wrote:
>>> 
>>>> Looks good. Make sure to run new test with -Xcomp and -XX:-TieredCompilation and Client VM.
>>> 
>>> Thanks for the review. I checked the test runs fine in these cases.
>>> 
>>> Roland.
>>> 
>>>> 
>>>> Thanks,
>>>> Vladimir
>>>> 
>>>> On 1/5/15 8:38 AM, Roland Westrelin wrote:
>>>>> http://cr.openjdk.java.net/~roland/8063086/webrev.00/
>>>>> 
>>>>> With 8029302, C2 computes x^2 as x*x. The interpreter and C1 code don’t have the special case code and as a result an application can see different result for the same computation whether it’s executed by the interpreter/c1 or c2. Fixed by adding the special case to the interpreter and C1.
>>>>> 
>>>>> Roland.
>>>>> 
>>> 
>>