xbolva00 marked an inline comment as done. xbolva00 added inline comments.
================ Comment at: lib/Sema/SemaExpr.cpp:11067 + + // Do not diagnose 2 ^ 64, but allow special case (2 ^ 64) - 1. + if (SubLHS && SubRHS && (LeftSideValue != 2 || RightSideValue != 64)) ---------------- xbolva00 wrote: > aaron.ballman wrote: > > aaron.ballman wrote: > > > This comment explains what the code does, but not why it does it. Given > > > that we're adding special cases, I think more comments here explaining > > > why this is valuable would be appreciated. > > Thank you, the comments helped! But they also raised another question for > > me. What's special about 2^64? Why not (2^16) - 1 or other common > > power-of-two values? I would have expected 8, 16, 32, and 64 to be handled > > similarly. > We generally suggest 1LL << C. But here we cant say 1LL << 64. > > (2^16)-1 is diagnosed normally since we go here from “visit xor” code. > ^^^^ > > This (2^64)-1 handling was suggested by jfb. > > I see no motivation cases to diagnose 2^65, 2^100, ... > > > > I think the suggestion for (2^32)-1: (1LL<32)-1 is good, or should we make things more complicated and suggest Int max macro? CHANGES SINCE LAST ACTION https://reviews.llvm.org/D66397/new/ https://reviews.llvm.org/D66397 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
