This is the mail archive of the mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [patch] Add tree-ssa-loop.h and friends.

On 10/08/2013 08:35 AM, Andrew MacLeod wrote:
On 10/08/2013 07:38 AM, Andrew MacLeod wrote:
On 10/08/2013 05:57 AM, Richard Biener wrote:

Index: loop-iv.c
*** loop-iv.c   (revision 203243)
--- loop-iv.c   (working copy)
*************** along with GCC; see the file COPYING3.
*** 62,67 ****
--- 62,68 ----
   #include "df.h"
   #include "hash-table.h"
   #include "dumpfile.h"
+ #include "tree-ssa-loop-niter.h"

loop-iv.c is RTL land (likewise loop-unroll.c and loop-unswitch.c),
why do they need tree-ssa-loop-niter.h?

Apart from that the patch is ok.

we've got a bit of a mess in a number of places... I've cleaned up a few of the easy ones I found.

This file is required for record_niter_bound(), max_loop_iterations_int() and estimated_loop_iterations_int().. so all bounds estimations. There was enough of an infrastructural requirement for these routines within the file that I decided it was beyond the scope of what I'm doing at the moment to split them out.

Eventually I'd like to break this up into modules and make sure that thing aren't creeping in from the wrong places, and restructure a bit... Loop suffer from that (like here), cfg has a couple of places where either rtl or generic cfg routines care calling into a routine that can understand SSA. I noted one in one of the earlier patches that I'll have to get back to. This sort of thing has in fact prompted me to start looking now at our include web and what should be within the logical modules so we can more easily identify these sorts of things.

Too many things to clean up!! I think I could be doing this sort of thing for the next 8 months easily :-)

I'd prefer to come back and revisit this with a followup to try to split tree-ssa-loop-niter.c into another component, maybe loop-niter.[ch]...


I just took a quick stab at it... I think its pretty involved and someone with better loop comprehension should probably look at the followup of removing that requirement. estimate_numbers_of_iterations_loop() in particular uses last_stmt(), so it requires gimple.. and there is sprinkling of gimple specific stuff all through it... I have no idea how this is suppose to work for rtl.

This is the way it is now, so at least by including that header, it exposes the hidden problem and either I can revisit it later, or someone else can tackle that. it seems *really* messy.

OK as is for now?

heh, make it available, and it will get used :-) It hasn't been this that way that long.

  2012-04-18  Richard Guenther  <>

        PR tree-optimization/44688
        * cfgloop.h (record_niter_bound): Declare.
        * tree-ssa-loop-niter.c (record_niter_bound): Export.
        Update the estimation with the upper bound here...
        (estimate_numbers_of_iterations_loop): ... instead of here.
        Do not forcefully reset a recorded upper bound.

2012-10-08  Jan Hubicka  <>

        * loop-unswitch.c (unswitch_single_loop): Use
        estimated_loop_iterations_int to prevent unswitching when loop
        is known to not roll.
        * loop-unroll.c (decide_peel_once_rolling): Use
        (unroll_loop_constant_iterations): Update
        nb_iterations_upper_bound and nb_iterations_estimate.
        (decide_unroll_runtime_iterations): Use
        estimated_loop_iterations or max_loop_iterations;
        (unroll_loop_runtime_iterations): fix profile updating.
        (decide_peel_simple): Use estimated_loop_iterations
        and max_loop_iterations.
        (decide_unroll_stupid): Use estimated_loop_iterations
        ad max_loop_iterations.
        * loop-doloop.c (doloop_modify): Use max_loop_iterations_int.
        (doloop_optimize): Likewise.
        * loop-iv.c (iv_number_of_iterations): Use record_niter_bound.
        (find_simple_exit): Likewise.
        * cfgloop.h (struct niter_desc): Remove niter_max.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]