Request for reviews (S): 6910664: C2: java/util/Arrays/Sorting.java fails with DeoptimizeALot flag

[Vladimir Kozlov]

Thank you, Tom

Yes, you are right, I did not thought that I can use Location::normal.
Then the comment in the .ad files is wrong.

I can fix C1 also if you point me the place.

Thanks,
Vladimir

Tom Rodriguez wrote:
> I'm not sure that's the right fix.  The whole point of float_in_dbl is to deal with x86 FPU registers so converting it into some platform dependent thing based on UseSSE doesn't seem right.  I think Matcher::float_in_double should be false if UseSSE >= 1 in x86_32.ad and should always be false in x86_64.ad.  In that case it will use Location::normal instead which will do:
> 
>       // Just copy all other bits straight through
>       union { intptr_t p; jint ji;} value;
>       value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
>       value.ji = *(jint*)value_addr;
>       return new StackValue(value.p);
> 
> which is equivalent to your new create_float_stack_value logic.
> 
> How did we go for so long with this being broken?  It's totally wrong on 64 bit.  C1 has the same problem too.
> 
> tom
> 
> On Feb 18, 2010, at 7:08 PM, Vladimir Kozlov wrote:
> 
>> http://cr.openjdk.java.net/~kvn/6910664/webrev.02
>>
>> Fixed 6910664: C2: java/util/Arrays/Sorting.java fails with DeoptimizeALot flag
>>
>> Problem:
>> The test has several java float locals and use XMM registers in debug info.
>> But the code which restore these values during deoptimization was not
>> updated for XMM registers usage. It assumes that float values were converted
>> to double on stack as it was before SSE hardware when FPU was used.
>>
>> Solution:
>> Add platform specific method to get float stack value from compiled frame.
>>
>> Reviewed by:
>>
>> Fix verified (y/n): y, test with -XX:UseSSE=0|1|2
>>
>> Other testing:
>> JPRT
>>
>