https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81876
--- Comment #5 from rguenther at suse dot de <rguenther at suse dot de> --- On Tue, 5 Dec 2017, law at redhat dot com wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81876 > > --- Comment #4 from Jeffrey A. Law <law at redhat dot com> --- > Richi. > > I do worry about cases where we exploit strict-overflow semantics. It'd be > nice to be able to warn about them, but I certainly agree that stability is a > problem. The main issue with this warning is that it warns about perfectly valid code... IMHO warning about simplifying a_1 + 1 > a_1 is not about strict-overflow but is in the "comparison is always true" class. But suggesting that there's a overflow issue in the code is misleading. > On the other hand those warnings (particularly those that result from ldist) > are highlighting real issues. Bogus user code, poor optimization, even > under-specified language from ISO. Examples of all can be found in BZ. Well... see above. Optimization is never perfect and passes doing code-generation do rely on followup passes to optimize things.
