dblaikie added inline comments.
================ Comment at: clang/lib/CodeGen/Address.h:30 + // Int portion stores lower 3 bits of the log of the alignment. + llvm::PointerIntPair<llvm::Type *, 3, unsigned> ElementType; ---------------- aeubanks wrote: > nikic wrote: > > Are we guaranteed 3 bits even on 32-bit architectures? > Apparently not, a static assert fires for a 32-bit build of clang. I was > assuming 3 was fine based on the PointerIntPair comments. > ``` > /// PointerIntPair - This class implements a pair of a pointer and small > /// integer. It is designed to represent this in the space required by one > /// pointer by bitmangling the integer into the low part of the pointer. This > /// can only be done for small integers: typically up to 3 bits, but it > depends > /// on the number of bits available according to PointerLikeTypeTraits for the > /// type. > ``` > > I suppose we could have a separate 32-bit vs 64-bit implementation of > `Address`, although that's not very nice. You can get more spare bits by overaligning the type that you're pointing to, if that's suitable/workable. We do that in a few places in LLVM for this sort of reason. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D117262/new/ https://reviews.llvm.org/D117262 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
