Anastasia added a subscriber: rjmccall.
Anastasia added inline comments.
================
Comment at: clang/lib/Sema/SemaCast.cpp:2352
+ if (SrcType == DestType ||
+ (Self.LangOpts.OpenCL &&
+ Self.Context.removeAddrSpaceQualType(SrcType) ==
----------------
I am thinking of whether we can allow something weird to be written by relaxing
this address space case
```
local int i;
const global int & ii = reinterpret_cast<global int>(i);
```
I think this code is completely meaningless as it requires creating a temporary
in global address space? I am not sure what we will even emit in IR?
Embedded C doesn't regulate the conversions between non-pointer types with
different address spaces but in OpenCL C we have allowed them apparently
https://godbolt.org/z/9f75zxj7v. I am not sure whether this was done
intentionally or not.
However, in C there are no references and other features that might create
problems.
At the same time it seems C++ allows casting away `const`
https://godbolt.org/z/fo3axbq3e
But it contradicts the comment below:
```
// C++ 5.2.10p2 has a note that mentions that, subject to all other
// restrictions, a cast to the same type is allowed so long as it does not
// cast away constness. In C++98, the intent was not entirely clear here,
// since all other paragraphs explicitly forbid casts to the same type.
// C++11 clarifies this case with p2.
```
I would like to see if @rjmccall has any opinion on whether reinterpreting
between non-pointer types with different address spaces is reasonable?
================
Comment at: clang/test/SemaOpenCLCXX/reinterpret-cast.clcpp:1
+// RUN: %clang_cc1 %s -pedantic -verify -fsyntax-only
+
----------------
Btw I assume your patch also allows reinterpret_cast between vectors? What
happens if we cast b/w vector of 3 elements and vector of 4 elements?
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D101519/new/
https://reviews.llvm.org/D101519
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