John Regehr on "Use of Assertions"

[Nick Sabalausky (Abscissa)]

On 09/05/2018 03:35 PM, Meta wrote:
> 
> I think the only sane way to use asserts as an 
> optimization guide is when the program will abort if the condition does 
> not hold. That, to me, makes perfect sense, since you're basically 
> telling the compiler "This condition must be true past this assertion 
> point, because otherwise program execution will not continue past this 
> point". You're ensuring that the condition specified in the assert is 
> true by definition. Not having that hard guarantee but still using 
> asserts as an optimization guide is absolutely insane, IMO.

I'd certainly agree with this.

Frankly though, I've always found `-release` itself to be a horrible 
thing to use, and I never go anywhere near it. It's a classic case of 
premature optimization, pure and simple - and a dangerous one at that.

IMO the only time an assert should be omitted (note: *an* assert, none 
of this module-level granularity stuff), even in release mode, is when 
you can verify that leaving the assert in would be prohibitively 
expensive: For example, frequent integrity checks on large trees, or 
bounds-checking an inner-loop of a performance-critical codepath.

Removing an assert in release mode is exactly the same as declaring 
"This part can't ever fail, so let's not worry about 'What happens if it 
does fail?'" (if you're THAT certain, why did you write the assert there 
in the first place???). TBH, I'm very surprised that Walter would ever 
be in favor of it.