asavonic added inline comments.
================ Comment at: clang/lib/CodeGen/CGExpr.cpp:4554 + + // Language rules define if it is legal to cast from one address space + // to another, and which address space we should use as a "common ---------------- bader wrote: > asavonic wrote: > > sdmitriev wrote: > > > bader wrote: > > > > Anastasia wrote: > > > > > What language rules? > > > > I suppose it's a generic note and author didn't meant some particular > > > > language here. This change was contributed by @sdmitriev. > > > > @sdmitriev, could you clarify, please? > > > This comment was originally added by @asavonic to > > > clang/lib/CodeGen/CGExprScalar.cpp (lines 2962-2965 in this patch), and > > > later I reused his code along with the comment in this file while fixing > > > a very similar issue. So, I guess it would be more correct to ask Andrew > > > to clarify. @asavonic, can you please comment on this? > > > This comment was originally added by @asavonic to > > > clang/lib/CodeGen/CGExprScalar.cpp (lines 2962-2965 in this patch), and > > > later I reused his code along with the comment in this file while fixing > > > a very similar issue. > > > > There is `if (Opts.SYCLIsDevice)` In CGExprScalar.cpp, so we handle SYCL > > language rules. > > In SYCL, (almost) all pointers have default address space in AST, but in CG > > some pointers become private/local/global, and some are lowered as generic > > pointers. We need to add an implicit addrspacecast in CG to emit an > > expression that expects the same type for its operands. > > > > For example: > > const char *str = ... ; > > const char *phi_str = i > 2 ? str : "hello world!"; > > > > In AST types of `str` and `"hello world"` are the same (`const char *`). In > > CG we emit `str` as `i8 addrspace(4)*` and `"hello world"` as `i8*`. At > > this point we have to decide what type `phi_str` should have, and > > addrspacecast the operands accordingly. > Is it possible to avoid fixing address space mismatch at this point by > adjusting AST as suggested by John in this comment: > https://reviews.llvm.org/D89909#inline-837495? > > I wonder if it can be done w/o impacting C++ template metaprogramming as > noted in this thread: > http://clang-developers.42468.n3.nabble.com/RFC-Re-use-OpenCL-address-space-attributes-for-SYCL-td4068754.html. > Is it possible to avoid fixing address space mismatch at this point by > adjusting AST Some address space mismatches are present in CG already, see CodeGenModule::getStringLiteralAddressSpace and CodeGenModule::GetGlobalVarAddressSpace. This should be moved to AST (or replaced) as well, right? Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D89909/new/ https://reviews.llvm.org/D89909 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
