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
----------------
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.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D89909/new/
https://reviews.llvm.org/D89909
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