Re: [Patch] OPT: Update heuristics for loop-invariant for address arithmetic.

[Jeff Law]

On 03/23/2015 10:35 AM, Ajit Kumar Agarwal wrote:
Hello All:
Did you get a chance to look at the below patch.

Thanks & Regards
Ajit

-----Original Message-----
From: gcc-patches-ow...@gcc.gnu.org [mailto:gcc-patches-ow...@gcc.gnu.org] On 
Behalf Of Ajit Kumar Agarwal
Sent: Wednesday, March 04, 2015 3:57 PM
To: vmaka...@redhat.com; GCC Patches
Cc: Vinod Kathail; Shail Aditya Gupta; Vidhumouli Hunsigida; Nagaraju Mekala
Subject: [Patch] OPT: Update heuristics for loop-invariant for address 
arithmetic.

Hello All:

The changes are made in the patch to update the heuristics for loop invariant 
for address arithemetic at RTL Level.
The heuristics are updated with the consideration of single def and use for 
register pressure calculation instead Of ignoring it and also to update the 
estimated register pressure cost along with the check of actual uses with 
Address uses.

With the above change, gains are seen in the Geomean for Mibench/EEMBC 
benchmarks for microblaze target. No Regression is seen in deja GNU regressions 
tests for microblaze.

Please let us know your feedback.

commit 039b95028c93f99fc1da7fa255f9b5fff4e17223
Author: Ajit Kumar Agarwal <ajitkum@xhdspdgnu.(none)>
Date:   Wed Mar 4 15:46:45 2015 +0530

     [Patch] OPT: Update heuristics for loop-invariant for address arithmetic.

     The changes are made in the patch to update the heuristics
     for loop invariant for address arithmetic. The heuristics is
     changed to incorporate the single def and use in the register
     pressure calculation in order to move the invariant out of
     loop. The heuristics are further changed to not to use the
     check for addr uses with actual uses. Also changes are done in
     the heuristics of estimated register pressure cost.

     ChangeLog:
     2015-03-04  Ajit Agarwal  <ajit...@xilinx.com>

             * loop-invariant.c (gain_for_invariant): update the
             heuristics for estimate_reg_pressure_cost.
             (get_inv_cost): Remove the check for addr uses with
             actual uses. Add the single def and use in the register
             pressure for invariants.
This work should probably be coordinated with the Intel folks who are 
looking to change if/when LICM for address expressions.

See the thread:

[PATCH, PR target/65103, 2/3] Propagate address constants into loops for 
i386

jeff