RFR(S): Bugfix: Clear High Word in Integer.bitCount() Intrinsic on SparcV9

John Rose john.r.rose at oracle.com
Mon Dec 17 17:39:10 PST 2012

On Dec 14, 2012, at 6:03 PM, David Chase wrote:

> There is also the possibility of a peephole-ish optimization (that can be informed by general flow analysis) that keeps track of zero bits in a word -- for instance, if the source of the data was a LDUW, there's no need to clear the bits.

We do some really hacky stuff in that vein; see the flag SparcV9RegsHiBitsZero.

The bug 8001436 requests a less hacky infrastructure for doing bitwise type propagation.


— John
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/attachments/20121217/c8b65e7c/attachment.html 

More information about the hotspot-compiler-dev mailing list