[LLVMdev] Prevent clang from replacing code with library calls

[Sean Silva]

On Thu, Aug 7, 2014 at 2:49 PM, Jim Grosbach <grosbach at apple.com> wrote:

>
> > On Aug 7, 2014, at 4:12 AM, Anton Korobeynikov <anton at korobeynikov.info>
> wrote:
> >
> >> I downloaded the latest NDK (r10) and compiled with the following cmd:
> >> arm-linux-androideabi-clang myMemcpy.c -S -fno-builtin -o0
> >> It still produces assembly with a call to "memcpy". Maybe the
> -fno-builtin
> >> is broken also in the latest release.
> > It's not broken. Even freestanding implementation is supposed to
> > provide mem* functions.
> >
>
> It’s also supposed to be possible to write a memcpy() implementation in C
> without the compiler’s idiom recognizer just transforming it into a call to
> the system memcpy(). -fno-builtin is supposed to be how to do that, right?
>

IIRC -ffreestanding might be the solution.

-- Sean Silva


>
> -jim
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