[llvm-commits] EmitLibCalls: check TargetLibraryInfo

[Nuno Lopes]

> On Tue, Jul 24, 2012 at 2:14 PM, Nuno Lopes <nunoplopes at sapo.pt> wrote:
>> Hi,
>>
>> Please find in attach a patch that makes EmitLibCalls consult the
>> TargetLibraryInfo data before creating a call to a library function. It
>> makes these Emit*() functions return 0 if the function is not available.
>>
>> Any comments?
>
> The convention of returning null is dangerous, as demonstrated by the
> fact that you messed it up in multiple places.  Maybe use
> llvm::Optional?
>
> Otherwise, looks fine.

Thanks for the review!
Actually returning null is really convenient in a number of places, since 
instcombine and simplifylibcalls interpret the return of null as "didn't 
change anything".  I've hopefully audited all call sites.

Nuno