Email: <amacleod AT SPAMFREE redhat DOT com>
This is the RABLE document from Nov. 2005 which lays out the design of a register allocator for GCC from scratch.
This is the followup thoughts, much less work : RABLET, which takes the main themes from RABLE and applies them to the out of ssa portion of the tree optimizers.
debuglocus is another old project on hold, details here: debuglocus
Work In Progress: C++0x memory model summary and impact on GCC