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Re: gcc compile for code size

From: Jeff Law <law at redhat dot com>
To: Andrew Haley <aph at redhat dot com>
Cc: Xin Tong <xerox dot time dot tech at gmail dot com>, gcc-help at gcc dot gnu dot org
Date: Sun, 11 Nov 2012 14:08:59 -0700
Subject: Re: gcc compile for code size
References: <CALKntY31amsELRdER_68aZsqFZFZBAPUrGcE3TO+Op8ZR_NQKQ@mail.gmail.com> <50A00276.2090002@redhat.com> <CALKntY36DqxjaYeg6ZNvw0KaNeDLu-oaRZK1WCS1h+HS__xogQ@mail.gmail.com> <50A01210.7020607@redhat.com>

On 11/11/2012 02:01 PM, Andrew Haley wrote:

On 11/11/2012 07:59 PM, Xin Tong wrote:

No.  GCC does all optimizations *except* those known to increase
program size.  This usually works pretty well, but isn't perfect.

so as to how the instructions are selected. compiling for code size
does not have an effect ?

Please don't top-post on this list.

Any target could, in principle, select instructions based on size
and -OS, but I don't know any that do.

Many ports look at at -Os and change their instruction selections, alignment requests, etc.

grep for "optimize_size" in the machine descriptions...

jeff

Follow-Ups:
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  - From: Andrew Haley

References:
- gcc compile for code size
  - From: Xin Tong
- Re: gcc compile for code size
  - From: Andrew Haley
- Re: gcc compile for code size
  - From: Xin Tong
- Re: gcc compile for code size
  - From: Andrew Haley

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