Re:Bugs found in GCC with the help of PVS-Studio
by 0xmohit on Saturday September 03, 2016 @06:14AM
(#12418604)
> a == 1 || a != 2 needs a warning
Yes, it needs a warning because it's kind of obvious that there is something amiss about this expression. Only the author could tell what was specifically wrong.
Re:Bugs found in GCC with the help of PVS-Studio
by raverbashing on Saturday September 03, 2016 @06:33AM
(#12418647)
Yes
I would advocate for the maintenance of both expressions if the comparison is tricky
If this is a hot path that must absolutely be optimized then a comment explaining the conditions is needed
And of course, the != 2 question might change (either because of a bug or logic change) but the == 1 might still be valid, however, if you took the first one your change will break the code
sometimes I may keep overlapping expressions in a statement to remind me of the triggers I'm looking for at this point - and would likely use some meaningful constant names for the 1 and 2
statements aren't just logic - they're often documentation too - especially on code you might not look at again for months
I used to have many arguments with a professor whose code I was working on - he would factor out everything in an expression - removing all the parentheses and rely on operator precedence - it was often impenetrable (for me) - so I'd unpack it, wrap parentheses everywhere, change single letter vars to meaningful ones etc. - he'd be in my office an hour later ranting