On 06/23/2015 01:36 AM, Janne Blomqvist wrote: > On Sun, Jun 21, 2015 at 4:57 PM, Thomas Koenig <tkoe...@netcologne.de> wrote: >> *ping* >> >> https://gcc.gnu.org/ml/gcc-patches/2015-06/msg00966.html >> >> >>> Hello world, >>> >>> the attached patch emits a warning for constant integer division. >>> While correct according to the standard, I cannot really think >>> of a legitimate reason why people would want to write 3/5 where >>> they could have written 0 , so my preference would be to put >>> this under -Wconversion (like in the attached patch). >>> >>> However, I am open to discussion on that. It is easy enough to >>> change. >>> >>> Regression-tested. Opinions? Comments? Would somebody rather >>> have -Wconversion-extra? OK for trunk? > > I'm a bit uncomfortable about this. IIRC I have code where I'm > iterating over some kind of grid, and I'm using integer division and > relying on truncation to calculate array indices. I can certainly > imagine that others have used it as well, and even that it's not a > particularly uncommon pattern. > > Furthermore, I think it's confusing that you have it under > -Wconversion, as there is no type conversion going on. > -Winteger-truncation maybe? > > Any other opinions? >
I am not sure it is worth warning about. I don't think it justifies its own compilation warning option. I have no objection to -Wconversion, 3/5 being converted to zero in a sense. It would help users catch a missing decimal point when they meant 3./5 Regards, Jerry Jerry