From: Richard Sandiford <richard.sandiford@linaro.org>
To: Tom de Vries <vries@codesourcery.com>
Cc: Zdenek Dvorak <rakdver@kam.mff.cuni.cz>, gcc-patches@gcc.gnu.org
Subject: Re: [PATCH PR45098, 4/10] Iv init cost.
Date: Wed, 25 May 2011 14:20:00 -0000 [thread overview]
Message-ID: <g4sjs2hp2r.fsf@linaro.org> (raw)
In-Reply-To: <4DD3F8E9.6000004@codesourcery.com> (Tom de Vries's message of "Wed, 18 May 2011 18:50:49 +0200")
Sorry for being so late. I was just curious...
Tom de Vries <vries@codesourcery.com> writes:
> The init cost of an iv will in general not be zero. It will be
> exceptional that the iv register happens to be initialized with the
> proper value at no cost. In general, there will at the very least be a
> regcopy or a const set.
>
> 2011-05-05 Tom de Vries <tom@codesourcery.com>
>
> PR target/45098
> * tree-ssa-loop-ivopts.c (determine_iv_cost): Prevent
> cost_base.cost == 0.
> Index: gcc/tree-ssa-loop-ivopts.c
> ===================================================================
> --- gcc/tree-ssa-loop-ivopts.c (revision 173380)
> +++ gcc/tree-ssa-loop-ivopts.c (working copy)
> @@ -4688,6 +4688,8 @@ determine_iv_cost (struct ivopts_data *d
>
> base = cand->iv->base;
> cost_base = force_var_cost (data, base, NULL);
> + if (cost_base.cost == 0)
> + cost_base.cost = COSTS_N_INSNS (1);
> cost_step = add_cost (TYPE_MODE (TREE_TYPE (base)), data->speed);
>
> cost = cost_step + adjust_setup_cost (data, cost_base.cost);
...why does this reasoning apply only to this call to force_var_cost?
Richard
next prev parent reply other threads:[~2011-05-25 13:45 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-17 7:23 [PATCH, PR45098] Tom de Vries
2011-05-17 7:25 ` [PATCH, PR45098, 1/10] Tom de Vries
2011-05-19 11:17 ` [PATCH PR45098, 1/10] Proc object-size fix Tom de Vries
2011-05-17 8:12 ` [PATCH, PR45098, 2/10] Tom de Vries
2011-05-18 9:39 ` Zdenek Dvorak
2011-05-17 8:30 ` [PATCH, PR45098, 3/10] Tom de Vries
2011-05-18 10:10 ` Zdenek Dvorak
2011-05-18 13:00 ` Tom de Vries
[not found] ` <20110518152457.GA13360@kam.mff.cuni.cz>
2011-05-18 19:30 ` Tom de Vries
2011-05-17 8:32 ` [PATCH, PR45098, 4/10] Tom de Vries
2011-05-18 17:46 ` [PATCH PR45098, 4/10] Iv init cost Tom de Vries
2011-05-18 22:59 ` Zdenek Dvorak
2011-05-25 14:20 ` Richard Sandiford [this message]
2011-05-26 12:24 ` Tom de Vries
2011-05-31 15:22 ` Richard Sandiford
2011-05-17 8:37 ` [PATCH, PR45098, 5/10] Tom de Vries
2011-05-18 17:48 ` [PATCH PR45098, 5/10] Bound cost Tom de Vries
2011-05-19 4:45 ` Zdenek Dvorak
2011-05-17 8:42 ` [PATCH, PR45098, 6/10] Tom de Vries
2011-05-18 17:48 ` [PATCH PR45098, 6/10] Bound cost - test cases Tom de Vries
2011-05-17 8:58 ` [PATCH, PR45098, 7/10] Tom de Vries
2011-05-18 17:52 ` [PATCH PR45098, 7/10] Nowrap limits iterations Tom de Vries
2011-05-19 4:45 ` Zdenek Dvorak
2011-05-20 12:22 ` Tom de Vries
2011-05-21 18:54 ` Zdenek Dvorak
2011-05-21 22:53 ` Tom de Vries
2011-05-28 17:58 ` Tom de Vries
2011-05-30 15:12 ` Zdenek Dvorak
2011-05-31 9:07 ` Tom de Vries
2011-05-31 9:11 ` Zdenek Dvorak
2011-06-11 10:13 ` Tom de Vries
2011-06-12 1:17 ` Zdenek Dvorak
2011-05-23 14:50 ` H.J. Lu
2011-05-17 9:03 ` [PATCH, PR45098, 8/10] Tom de Vries
2011-05-18 18:23 ` [PATCH PR45098, 8/10] Nowrap limits iterations - test cases Tom de Vries
2011-05-18 18:27 ` [PATCH PR45098, 9/10] Cheap shift-add Tom de Vries
2011-05-19 5:33 ` Zdenek Dvorak
2011-05-20 11:32 ` Tom de Vries
2011-05-20 20:09 ` Zdenek Dvorak
2011-05-21 15:05 ` Eric Botcazou
2011-05-22 19:33 ` Tom de Vries
2011-05-22 20:22 ` Richard Guenther
2011-05-22 21:11 ` Eric Botcazou
2011-05-17 10:03 ` [PATCH, PR45098, 9/10] Tom de Vries
2011-05-17 10:30 ` [PATCH, PR45098, 10/10] Tom de Vries
2011-05-18 18:30 ` [PATCH PR45098, 10/10] Cheap shift-add - test case Tom de Vries
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