Anastasia added inline comments.
================
Comment at: clang/test/SemaOpenCLCXX/reinterpret-cast.clcpp:15
+ int4 i4;
+ auto i4_to_i3 = reinterpret_cast<int3>(i4); //
expected-error{{reinterpret_cast from vector 'int4' (vector of 4 'int' values)
to vector 'int3' (vector of 3 'int' values) of different size}}
+
----------------
I think in OpenCL vector 3 should be setup as vector 4 in memory with the 4th
component being `undef` value. So this conversion should be permitted.
For example you can reinterpret cast between 3 and 4 components vectors using
as_typen functions.
https://godbolt.org/z/sKqnYhnGe
I don't think we have a comprehensive description but these are the quotes from
OpenCL C:
>For 3-component vector data types, the size of the data type is 4 *
>sizeof(component). This means that a 3-component vector data type will be
>aligned to a 4 * sizeof(component) boundary. The vload3 and vstore3 built-in
>functions can be used to read and write, respectively, 3-component vector data
>types from an array of packed scalar data type.
> When the operand and result type contain a different number of elements, the
> result shall be implementation-defined except if the operand is a 4-component
> vector and the result is a 3-component vector. In this case, the bits in the
> operand shall be returned directly without modification as the new type.
> The suffixes .lo (or .even) and .hi (or .odd) for a 3-component vector type
> operate as if the 3-component vector type is a 4-component vector type with
> the value in the w component undefined.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D101519/new/
https://reviews.llvm.org/D101519
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
