[PATCH] D58463: [CUDA]Delayed diagnostics for the asm instructions.

[Alexey Bataev via Phabricator via cfe-commits]

ABataev added a comment.

In D58463#1410900 <https://reviews.llvm.org/D58463#1410900>, @tra wrote:

> There's a new quirk we've ran into after this patch landed. Consider this code:
>
>   int foo() {
>     int prev;
>     __asm__ __volatile__("mov %0, 0" : "=a" (prev)::);
>     return prev;
>   }
>
>
> When we compile for device, asm constraint is not valid for NVPTX, we emit delayed diag and move on. The function is never code-gen'ed so the diag never shows up. So far so good.
>
> Now we add `-Werror -Wininitialized` and things break -- because we bail out early, `prev` is left uninitialized and is reported as such.
>
>   $ bin/clang++ -c --cuda-gpu-arch=sm_35 asm.cu -nocudainc --cuda-device-only -Wuninitialized -Werror
>   asm.cu:4:10: error: variable 'prev' is uninitialized when used here [-Werror,-Wuninitialized]
>     return prev;
>            ^~~~
>   asm.cu:2:11: note: initialize the variable 'prev' to silence this warning
>     int prev;
>             ^
>              = 0
>   1 error generated when compiling for sm_35.
>  
>
>
> I think this should also show up in the test case in this patch, too, if you add -Wuninitialized


Hi Artem, I think we can just delay emission of this warning to solve this problem.


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