Re: [new-regalloc] What is the status on current sources

[Michael Hayes <m dot hayes at elec dot canterbury dot ac dot nz>]

Geert Bosch writes:

 > Since it seems that flow.c is the place where we do our dataflow analysis,
 > I wonder why you decided to implement a new df.c unit. It seems to me
 > that it would be preferable to enhance the existing flow.c instead of
 > writing a different piece of code that mostly does the same.

You can blame me for this!  I wanted some dataflow routines to use
with the loop optimiser, primarily to calculate reaching definitions
and to generate def-use and use-def chains.  It was then trivial to
add live register analysis (what the life routines in flow.c
calculate) although I haven't finished dealing with hard registers
properly since the loop optimiser does not use them.  gcse.c also has
some routines for calculating reaching definitions but these were too
closely coupled to the gcse pass to be of generic use.  Adding this
capability to life_analysis required a major rewrite so I started with
a clean slate and tried to design an interface that would be easy to
use for other optimisation routines.

Michael.