[Bug c/6906] warn about asserts with side effects

[felix.von.s at posteo dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=6906

felix <felix.von.s at posteo dot de> changed:

           What    |Removed                     |Added
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                 CC|                            |felix.von.s at posteo dot de

--- Comment #7 from felix <felix.von.s at posteo dot de> ---
What's wrong with the __builtin_pure_p approach? Sure, the diagnostics
generated by __attribute__((warning)) will be ugly, but it's still something.
It's also very simple to implement: it's just !TREE_SIDE_EFFECTS().

In fact, I patched my copy of GCC to add __builtin_pure_p defined just like
that and it seems to work fine. Might submit it soon (I didn't write any tests,
though).