[llvm-commits] [PATCH] Move function prototype attribute inference to instcombine

[Chandler Carruth]

On Thu, Nov 29, 2012 at 11:25 PM, Owen Anderson <resistor at mac.com> wrote:
>
> On Nov 29, 2012, at 10:16 PM, Duncan Sands <baldrick at free.fr> wrote:
>
>> Hi Meador,
>>
>> On 30/11/12 06:22, Meador Inge wrote:
>>> The simplify-libcalls pass implemented a doInitialization hook to infer
>>> function prototype attributes for well-known functions.  Now that library
>>> call simplification is being carried out in instcombine it makes sense to
>>> move the attribute inference there as well.
>>
>> I'm not a big fan of doInitialization personally.  Couldn't you do it lazily
>> the first time that they are needed instead?
>
> Indeed, Pedro has been working with the ASAN/TSAN guys to clean up and remove this kind of behavior in doInitialization on their passes.

Yea, I don't know why this was ever remotely OK to do in
doInitialization. It's terrible.

I feel like this should be part of the existing 'functionattrs' pass
which is already responsible for inferring attributes to functions,
just as instcombine was already responsible for scalar
simplifications.

If we need to share the logic for matching a textual function name to
a particular library routine, that should be shared with a common bit
of C++ code, not by forcing these things into the same pass.