From: Richard Henderson <rth@redhat.com>
To: Bonzini <bonzini@gnu.org>
Cc: gcc@gnu.org
Subject: Re: Marking variable as addressable from within SSA pass
Date: Fri, 19 Mar 2004 21:57:00 -0000 [thread overview]
Message-ID: <20040319200037.GB26527@redhat.com> (raw)
In-Reply-To: <20040319160636.GA22342@fencepost>
On Fri, Mar 19, 2004 at 11:06:36AM -0500, Bonzini wrote:
> The pass takes, for example,
>
> V4QI T_1;
> V4QI T_2;
> V4QI T_3;
> T_3 = T_1 & T_2;
>
> and converts it into
>
> V4QI T_1;
> V4QI T_2;
> V4QI T_3;
> unsigned int *T_4;
> unsigned int *T_5;
> unsigned int *T_6;
> unsigned int T_7;
> unsigned int T_8;
> T_4 = (unsigned int *) &T_1;
> T_5 = (unsigned int *) &T_2;
> T_6 = (unsigned int *) &T_3;
> T_7 = *T_4;
> T_8 = *T_5;
> T_9 = T_4 & T_5;
> *T_6 = T_9;
You do not want to do this. Addressing variables SEVERELY pessimizes
the code. Use a VIEW_CONVERT_EXPR to change the type instead.
r~
next prev parent reply other threads:[~2004-03-19 20:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-19 17:02 Bonzini
2004-03-19 21:57 ` Richard Henderson [this message]
2004-03-20 18:09 ` Paolo Bonzini
2004-03-20 22:08 ` Richard Henderson
2004-03-21 18:17 ` Paolo Bonzini
2004-03-21 23:07 ` Richard Henderson
2004-03-19 22:06 Richard Kenner
2004-03-19 22:09 ` Richard Henderson
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