[PATCH] D142305: [ADT] llvm::bit_cast - use __builtin_bit_cast if available

Tue Jan 24 13:14:11 PST 2023

dblaikie added a comment.

In D142305#4077555 <https://reviews.llvm.org/D142305#4077555>, @RKSimon wrote:

> In D142305#4077361 <https://reviews.llvm.org/D142305#4077361>, @dblaikie wrote:
>
>>> If the compiler supports __builtin_bit_cast we should try to use it instead of std::memcpy (and avoid including the cstring header).
>>
>> Why? Maintaining non-portable code has some cost, if we can get similar/sufficient/the same performance without special casing, that seems better. Do we not get adequate performance with `std::memcpy`? Is the header especially expensive to include?
>
> No strong preference tbh

Did something motivate proposing this change?

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  https://reviews.llvm.org/D142305/new/

https://reviews.llvm.org/D142305