Re: [PATCH] TRACING: Fix a copmile warning

From: Ian Lance Taylor
Date: Mon Jul 25 2011 - 20:44:39 EST


Steven Rostedt <rostedt@xxxxxxxxxxx> writes:

>> It seems gcc transforms the conditional from:
>>
>> if (a != NULL && b != NULL) ...
>>
>> to
>>
>> if (b != NULL && a != NULL) ...
>>
>> In which case the warning is fully valid. I'm not sure what's the C
>> standard guarantee in term of conditional test order. gcc 4.7.0 has
>> the same behavior.
>
> Yes it seems to be doing this :-/
>
> This is a real bug!

To be clear, gcc is not doing that, and this is not a code generation
bug. It is a warning generation bug; the generated code is correct.

Ian
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