Help with bit-field semantics in C and C++

[Mark Mitchell]

Gabriel Dos Reis wrote:

>Mark Mitchell <mark@codesourcery.com> writes:
>
>
>[...]
>
>| conversion instructions inserted.  Since EDG passes basically every
>| known testsuite,
>
>That is a very interesting argument.
>Who sits the baby-sitter, e.g. who makes sure that those testsuite are
>enough to make sure that a compiler that passes it is bug-free?
>Actually, by your argument, EDG should stop releasing any version of
>their front-ends -- yet they still release bug-fixes, even thiugh they
>have passed known  testsuites. 
>  
>
Huh?  That's a reduction-to-absurdity argument.

The people who write testsuites for a living think a lot about corner 
cases and try to write tests that cause compilers to get the corner 
cases wrong.  They go through the standard line-by-line, thinking of 
pathological things.  None of them have ever written the test that David 
is suggesting.  So, that doesn't mean David is wrong, in and of itself; 
he might have thought of something nobody else thought of.  But, I 
certainly consider the fact that no testsuite checks for this case as 
evidence against David's position.

-- 
Mark Mitchell
CodeSourcery, LLC
(916) 791-8304
mark@codesourcery.com