Re: [patch] tree-ssa-ccp.c: Propagate ADDR_EXPRs further.

[Jeffrey A Law <law at redhat dot com>]

On Fri, 2005-05-27 at 11:47 -0400, Kazu Hirata wrote:
> Hi Jeff,
> 
> > I'd like to see at least some measurement of compile-time impacts.
> 
> Here is a timing in seconds for five runs of cc1 -O2 for several cc1-i
> files.  (Actually each is run 6 times with the timing from the first
> run discarded to discount hot cache effects.)
> 
>                original patched   diff%
> c-common.i       22.403  22.338 -0.290%
> combine.i        18.668  18.676 +0.042%
> fold-const.i     42.545  42.531 -0.032%
> reload1.i        14.505  14.509 +0.027%
> reload.i         13.394  13.379 -0.111%
> insn-attrtab.i  200.815 200.856 +0.020%
Looks like noise to me.  I can speculate that we're much better
at systematically avoiding moving through the lattice -- ie
we're much better at identifying those objects which are VARYING
and thus avoiding a lot of transitions and re-evaluations.


I'm OK with the patch.  If you wouldn't mind, can you investigate
removing the fold_XXX_to_const routines?

Jeff