[RFC] [4.2] Address computation PRE

[Richard Henderson]

On Fri, Sep 30, 2005 at 08:06:45PM +0200, Paolo Bonzini wrote:
> Therefore I tried to implement a restricted, but faster and more 
> powerful form of GCSE: it looks at REG_EQUAL notes to detect address 
> computations, gathers all the instructions depending on the one with the 
> note, and treats them as a single entity for the sake of eliminating them.

Is there any real benefit to moving instructions, instead of emitting
new code and letting rtl DCE do its job?  If you do that, then adding
a few lines to the existing GCSE pass to look at (appropriate) REG_EQUAL
notes, and invoking emit_move_insn to rebuild the sequences would seem
simpler than a new pass.


r~