Missing evaluation on bugs 6914095, 6914113, 6933327, 6935994

[Vladimir Kozlov]

These bugs have evaluations in Comments section which unfortunately is 
not visible outside. I moved my comments to Evaluation section and 
included them below.

Vladimir

Vitaly Davidovich wrote:
>
> On your last one, have you checked to see if it makes a difference? I 
> believe using partial registers requires a prefix on the op, making 
> the instruction larger.  Also there are some partial register stalls 
> that can be triggered.
>
> On Oct 11, 2011 12:00 PM, "Ulf Zibis" <Ulf.Zibis at gmx.de 
> <mailto:Ulf.Zibis at gmx.de>> wrote:
>
>     Hi,
>
>     some time ago I have submitted these bugs:
>
>     6914095
>     <http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6914095> -
>     HotSpot should reuse invariant loop parameter
>
It would be nice if 32bit x86 had more registers. Unfortunately we have 
to reuse registers otherwise we will get more spills on stack which will 
cause more performance regression then keeping value in register. And 
x*c+c  is very fast (few cycles) on modern cpus.
*** (#3 of 3): 2010-11-09 15:31:21 PST vladimir.kozlov at oracle.com
>
>     6914113
>     <http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6914113> -
>     Copy int to byte[] in 1 step
>
Will not do this. C2 type system will not allow store int into byte 
array. Other platforms require address alignment to 4 bytes for int 
store. Also on platforms with different endian the result will be different.
*** (#2 of 2): 2010-08-25 14:51:13 PDT vladimir.kozlov at oracle.com

>     6933327
>     <http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6933327> - Use
>     shifted addressing modes instead of shift instuctions
>
Will not fix. Using  addressing mode involves addess unit which may have 
negative effect if you have memory access instructions near this code.
*** (#2 of 2): 2010-08-25 14:29:34 PDT vladimir.kozlov at oracle.com
>
>     6935994
>     <http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6935994> - Use
>     as less bits as necessary
>
Should not do this since the other part of register will not be 
initialized to 0.
*** (#2 of 2): 2010-08-25 14:39:10 PDT vladimir.kozlov at oracle.com

>
>     I do not see, why they have been closed as "Will Not Fix".
>
>     Can someone add content to the 'evaluation' section, or at least
>     explain reasons here?
>
>     Much thanks,
>
>     -Ulf
>
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