Re: List of optimizations enabled by -O1 seems incorrect

["Kevin P. Fleming" <kpfleming@digium.com>]

Andrew Haley wrote:
> Kevin P. Fleming wrote:
>> Nikos Chantziaras wrote:
>>
>>> Thanks for the tip.  Looking at the generated assembly files, I finally
>>> solved the "mystery": GCC uses SSE/SSE2 instructions to fetch both
>>> variables in one CPU instruction.  It's faster but circumvents
>>> short-circuit "if" rules and Valgrind prints an error.
>> Then that seems very broken; you should not have to have initialized a
>> variable to avoid this issue, since short-circuit evaluation is defined
>> in the C standard.
> 
> Yes, but it's covered by the "as if" rule: if no conforming program could
> ever notice the difference, an optimization is allowed.

Well, I guess that was my point, stated in another way. I'm certainly no
C standard expert, but I didn't think his program was 'non-conforming'
in any way.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
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