> On Jun 12, 2017, at 12:34 PM, Eli Friedman via Phabricator > <revi...@reviews.llvm.org> wrote: > > efriedma added inline comments. > > > ================ > Comment at: cfe/trunk/lib/CodeGen/CGExprScalar.cpp:2666 > + bool isSigned = > indexOperand->getType()->isSignedIntegerOrEnumerationType(); > + bool mayHaveNegativeGEPIndex = isSigned || isSubtraction; > + > ---------------- > This logic doesn't look quite right; what happens here if you write "p - > SIZE_MAX"?
This check is here in order to prevent false positives on expressions such as: "p - 1ULL". We fail to diagnose the overflow in "p - SIZE_MAX" both before and after r305216 because we turn it into a GEP which does "p + 1" too early. EmitCheckedGEP doesn't "know" that it's invalid for the result of the GEP to be greater than "p". I'll file a bug about this. vedant > > > Repository: > rL LLVM > > https://reviews.llvm.org/D33910 > > > _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
