On Oct 14, 2012, at 8:19 , Stephen Canon <[email protected]> wrote: > On Oct 12, 2012, at 12:38 PM, Richard Trieu <[email protected]> wrote: > >> This patch is for a new warning to Clang, called -Wlogical-not-compare. It >> is designed to catch the case where the user is attempting to negate a >> comparison, but only manages to negate the LHS because of missing parens. >> For instance, warn here: >> >> if (!x < 5) >> >> The user probably meant: >> >> if (!(x < 5)) >> >> or >> >> if (x >= 5) >> >> When emitted, the warning will have a note suggesting this as a fix-it (drop >> the not and inverting the comparison operator). > > If x has FP type, then !(x < 5) is not equivalent to (x >= 5); if x is NaN, > the first is true, but the second is false.
The fixit is on a note, so I personally think it's okay that it doesn't perfectly match the semantics of the existing expression. I think most people ignore NaNs when writing casual floating-point code. Jordan _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
