[PATCH] D96853: [clang][AVR] Support variable decorator '__flash'

[Anastasia Stulova via Phabricator via cfe-commits]

Anastasia added a comment.

In D96853#2660443 <https://reviews.llvm.org/D96853#2660443>, @benshi001 wrote:

> In D96853#2659266 <https://reviews.llvm.org/D96853#2659266>, @Anastasia wrote:
>
>> Btw is any pointer conversion between address space 1 and the default address space allowed? I.e. is the following code valid:
>>
>>   __flash static const int var1[] = {111, 222, 333};
>>   void foo(int*);
>>   ....
>>   foo(var1);
>>
>> or
>>
>>   __flash static const int var1[] = {111, 222, 333};
>>   void foo(int*);
>>   ....
>>   foo((int*)var1);
>>
>> ?
>
> No. clang denied with `error: passing 'const __attribute__((address_space(1))) int *' to parameter of type 'const int *' changes address space of pointer` while avr-gcc accepted it.
>
> It seems I need more efforts to make clang-avr fully compatible with avr-gcc.

Ok, it makes sense for clang to align with gcc in general but do you know whether or where this conversions are described? By default if not specified explicitly implicit conversions are always disallowed in  `ISO/IEC DTR 18037` and explicit casts are always allowed but can yeild undefined behavior if address spaces don't overlap.


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