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Re: Optimization flags not working (GCC 4.2.4)

From: slnc <s at slnc dot me>
To: "John (Eljay) Love-Jensen" <eljay at adobe dot com>
Cc: "gcc-help at gcc dot gnu dot org" <gcc-help at gcc dot gnu dot org>
Date: Sat, 04 Apr 2009 01:55:24 +0200
Subject: Re: Optimization flags not working (GCC 4.2.4)
Authentication-results: slnc.net from=s@slnc.me; sender-id=neutral; spf=neutral
References: <49D66423.6080204@slnc.me> <204DEA5423F3BF47A6EE88C4E2979EC66BE84EDAE6@nambx04.corp.adobe.com>

Hi John,

Thank you but -O0 makes no difference.

gcc -c -g -O0 -fdefer-pop -fdelayed-branch -fguess-branch-probability -fcprop-registers -fif-conversion -fif-conversion2 -ftree-ccp -ftree-dce -ftree-dominator-opts -ftree-dse -ftree-ter -ftree-lrs -ftree-sra -ftree-copyrename -ftree-fre -ftree-ch -funit-at-a-time -fmerge-constants main.c

(those are all gcc 4.2.4 optimization flags for level -O1 according to the docs) generates the same unoptimized code. Changing -O0 with -O1 generates the optimized version.

John (Eljay) Love-Jensen wrote:

Hi Juan,

If you are not optimizing (-O0), the optimization -f flags have no effect.
HTH,
--Eljay

--
Juan Alonso

Follow-Ups:
- Re: Optimization flags not working (GCC 4.2.4)
  - From: David Daney

References:
- Optimization flags not working (GCC 4.2.4)
  - From: slnc
- RE: Optimization flags not working (GCC 4.2.4)
  - From: John (Eljay) Love-Jensen

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