Request for reviews (M): 6954029: Improve implicit null check generation with compressed oops

[Christian Thalinger]

On Thu, 2010-05-20 at 18:02 -0700, Vladimir Kozlov wrote:
> http://cr.openjdk.java.net/~kvn/6954029/webrev
> 
> Fixed 6954029: Improve implicit null check generation with compressed oops
> 
> Problem:
> When DecodeN instruction does not fold into address expression
> it may prevent implicit null check generation if it is scheduled
> below the null check since the corresponding memory instruction
> could not be moved.
> 
> Solution:
> If needed move DecodeN instruction before null check to generate
> implicit null check.
> 
> I also removed code which switch off default COOP usage on N1:
> currently generated COOP code perform better on N1 (tested jbb2005).

src/cpu/sparc/vm/sparc.ad:
src/cpu/x86/vm/x86_64.ad:

+   assert(UseCompressedOops, "only for comressed oops code");
                                           ^ typo

Otherwise (I think) it's OK.

-- Christian