The server compiler currently computes block frequencies based on branch estimates and probabilities collected from profiling data.

The frequency data can be leveraged create a block layout that:
  - reduces the number of branches emitted
  - improves icache locality
  - rotates loops to end with a conditional branch
  - naturally moves uncommon code sequences out of line without using an arbitrary frequency cutoff

While only modest improvement in performance should be expected, a reduction in the methods for which "spaghetti code" is emitted, should make assembly code more readable.
Posted Date : 2008-09-02 20:45:05.0

N/A

Create a post-register allocation pass that drives block layout by edge frequencies.
Posted Date : 2008-09-02 20:48:46.0

http://hg.openjdk.java.net/jdk7/hotspot-comp/hotspot/rev/72c5366e5d86
Posted Date : 2008-11-07 01:29:49.0