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Re: PRE in gcse.c
- To: Alexander Larsson <alla at lysator dot liu dot se>
- Subject: Re: PRE in gcse.c
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Fri, 06 Nov 1998 20:57:19 -0700
- cc: egcs at cygnus dot com
- Reply-To: law at cygnus dot com
In message <199811061539.QAA07175@c125.ryd.student.liu.se>you write:
> Out of interest i checked out what kind of gcse egcs used and saw that it
> uses
> an older version of partial redundancy elimination described by Morel and
> Renvoise. I am not very familiar with the gcc source, and i haven't looked
> very deeply at this, but would there be any interest in an LCM version of
> gcse.c? This has two advantages, first register life-times are minimized
> and second the data-flow analysis is (supposedly) simpler and faster.
Cygnus will be donating a lcm implementation I wrote later this year.
> In the source i did find a comment that said:
> Eventually it would be nice to replace cse.c/gcse.c with SSA (static
> single
> assignment) based GVN (global value numbering). L. T. Simpson's paper
> (Rice University) on value numbering is a useful reference for this.
SSA is further out, but we are putting the pieces in place.
jeff