[llvm-dev] LLVM 3.9 RC2's SCCP pass removing calls to external functions?!

[Renato Golin via llvm-dev]

On 24 August 2016 at 11:45, Alexandre Isoard <alexandre.isoard at gmail.com> wrote:
> However, he also stated that in the case the functions returns void it is
> not removed, which suggest there is something fishier going on.

Looking back at the example (and LangRef, for function attributes),
looks like it's not legal to remove because the function does *not*
have "readnone" or "readonly", so LLVM can't prove it side-effect
free.

Sanjoy's fix is probably on the right track.

--renato