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Re: updated code size comparison
- From: John Regehr <regehr at cs dot utah dot edu>
- To: Paolo Bonzini <bonzini at gnu dot org>
- Cc: gcc at gcc dot gnu dot org, llvmdev at cs dot uiuc dot edu
- Date: Thu, 17 Dec 2009 10:22:39 -0700 (MST)
- Subject: Re: updated code size comparison
- References: <4B284431.9050305@cs.utah.edu> <4B28A7B6.8010303@gnu.org>
Hi Paolo,
I would also avoid testcases using volatile. Smaller code on these testcases
is often a sign of miscompilation rather than optimization. For example,
http://embed.cs.utah.edu/embarrassing/src_harvested_dec_09/076389.c is
miscompiled on GCC 3.4 and SunCC 5.10.
Yeah, there are definitely several examples where small code is generated
by miscompilation, especially of volatiles.
However I would prefer to leave these testcases in, unless there is a
strong feeling that they are too distracting. They serve as poignant
little reminders about how easy it is to get volatile wrong...
John