David Rowley <dgrowley@gmail.com> writes: > On 25 December 2014 at 00:34, Andres Freund <andres@2ndquadrant.com> wrote: >> I really wonder if we can't make msvc reliably recognize this kind of >> scenario - especially this case is pretty trivial?
> The attached patch removes the warning, but likely can't be used in case > someone somewhere is doing elog(var++, "my error");
Yeah, we're *not* doing that. There are definitely places where ereport/elog are used with nonconstant elevel.
Agreed. The patch was intended as a demo of where the problem is. Although I don't see why non-const elevel matters. Non-stable expressions are what actually matter.
It's curious though that MSVC fails to notice that the variable never changes. I wonder whether we could get away with changing the elog macro to do const int elevel_ = (elevel); as ereport does, and whether it would help if so.
Unlikely, as the one that was just fixed above is an ereport.
I'll dig around a little more and see if there's some way to get MSVC to optimise this somehow. The 1% reduction in the postgres.exe seems worth a little bit of investigation time.
