Request for reviews (S): 7097546: Optimize use of CMOVE instructions

[Vladimir Kozlov]

I want this info in product VM also but Verbose and WizardMode are debug flags. You can use 1 compiler thread to get 
more linear output.

Vladimir

On 11/4/11 3:35 AM, Christian Thalinger wrote:
>
> On Oct 22, 2011, at 1:23 AM, Vladimir Kozlov wrote:
>
>> http://cr.openjdk.java.net/~kvn/7097546/webrev
>>
>> 7097546: Optimize use of CMOVE instructions
>>
>> Avoid CMove in a loop if possible. May generate CMove if it could be moved outside a loop. Don't generated CMoveD/CmoveF: it is expensive to compute both float/double values + cmove. Note, on x86 when SSE>=2 (all modern cpus) CMoveD/CMoveF mach instructions are implemented as jmp+move. Don't generated CMove when BlockLayoutByFrequency optimization moves infrequent branch from hot path. Added Cmove mach instructions with jmp+move to x86 when there is no HW cmove instruction.
>>
>> Main part of changes in loopopts.cpp is coding style correction.
>>
>> Print size of compiled method and compilation time when PrintCompilation and PrintInlining are specified on command line. I thought first to print it with just PrintCompilation but it will double output.
>
> I kind of missed this but could we print this only with Verbose or WizardMode?  It makes the output more difficult to read.
>
> -- Chris
>
>>
>> No effect on refworkload but it will help later for 6890673 fix. Verified with microbenchmark I wrote (attached to the bug report).
>>
>> Thanks,
>> Vladimir
>