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Re: strlen optimizations based on whether stpcpy is declared?
On Mon, 2 Oct 2017, Martin Sebor wrote:
> IMO, a reasonable question a GCC user might ask is: when I make
> a call to a standard library function via __builtin_foo() in
> a language conformance mode where foo is not a standard function,
> can I expect GCC to transform it to some equivalent call to
> a function that is defined by the standard (or expand it inline)?
> I don't know what the answer should be, but whatever we might
> want it to be, it seems worth documenting.
It may transform it, but is not required to do so; calling foo is also OK.
<https://gcc.gnu.org/ml/gcc-patches/2014-12/msg00409.html> has my
analysis of what I think is correct in this area (which may not be the
same as what is currently implemented).
Joseph S. Myers