[Issue 18016] using uninitialized value is considered @safe but has undefined behavior

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18016

--- Comment #12 from Steven Schveighoffer <schveiguy at yahoo.com> ---
(In reply to anonymous4 from comment #10)
> AFAIK, Walter's suggestion is not supported by LLVM. Currently LLVM removes
> code that uses uninitialized value. To work it around LDC will need to
> initialize variables initialized with void and provide an different way to
> declare uninitialized variables. Likely not a problem, but results in minor
> fragmentation of language. I believe LDC way will have a priority, because
> DMD is not really about performance anyway, so default initialized variables
> for it are good enough.

I don't understand how the suggestion that the behavior is implementation
defined doesn't jive with LLVM's chosen behavior.

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