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Re: [PATCH PR45098, 7/10] Nowrap limits iterations

From: Zdenek Dvorak <rakdver at kam dot mff dot cuni dot cz>
To: Tom de Vries <vries at codesourcery dot com>
Cc: gcc-patches at gcc dot gnu dot org
Date: Wed, 18 May 2011 23:11:58 +0200
Subject: Re: [PATCH PR45098, 7/10] Nowrap limits iterations
References: <4DD21F6E.4050308@codesourcery.com> <4DD221CF.4040002@codesourcery.com> <4DD3FD79.2020804@codesourcery.com>

Hi,

> This patch attemps to estimate the number of iterations of the loop based on
> nonwrapping arithmetic in the loop body.
> 
> 2011-05-05  Tom de Vries  <tom@codesourcery.com>
> 
> 	PR target/45098
> 	* tree-ssa-loop-ivopts.c (struct ivopts_data): Add fields
> 	max_iterations_p and max_iterations.
> 	(is_nonwrap_use, max_loop_iterations, set_max_iterations): New function.
> 	(may_eliminate_iv): Use max_iterations_p and max_iterations.
> 	(tree_ssa_iv_optimize_loop): Use set_max_iterations.

what are the cases this handles better than the existing analysis of maximum numbers of iterations
(estimate_numbers_of_iterations)?  Would it be possible to add the handling of these cases
to estimate_numbers_of_iterations, rather than doing it just for ivopts?

Zdenek

Follow-Ups:
- Re: [PATCH PR45098, 7/10] Nowrap limits iterations
  - From: Tom de Vries

References:
- [PATCH, PR45098]
  - From: Tom de Vries
- [PATCH, PR45098, 7/10]
  - From: Tom de Vries
- [PATCH PR45098, 7/10] Nowrap limits iterations
  - From: Tom de Vries

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