[LLVMdev] folding x * 0 = 0

[Chris Lattner]

On Mar 3, 2010, at 12:41 PM, Jochen Wilhelmy wrote:

> 
>> I'm not sure how that would work, but it most likely wouldn't fit with the design of llvm.  If this is important, I'd rather fix the representational issue.
>> 
>>  
> Just
> #ifdef RELAXED_FLOAT
> here the code like I posted
> #endif

Ok, that's what I thought, we don't want that in mainline.

> what do you mean by the representational issue? something in the IR?

Yes.  Each fp operation should have the information tagged onto like (like nuw/nsw on integer ops).  This allows inlining between functions with different settings, allows expressing things like the fortran parentheses rules etc.

-Chris