[llvm-commits] annotate known function declarations in SimplifyLibCalls pass

[Chris Lattner]

On Jan 1, 2009, at 5:49 PM, Nick Lewycky wrote:

> This patch modifies SimplifyLibCalls to run a post-pass that adds  
> attributes to many well-known functions. I'm sending this out for  
> review because there's a lot of decisions I made that should be  
> checked before the commit:

In addition to Duncan's comments, please add a helper method for this  
pattern:

> +          if (!F.doesNotThrow()) {
> +            F.setDoesNotThrow();
> +            ++NumAnnotated;
> +            Modified = true;
> +          }
> +          if (!F.paramHasAttr(1, Attribute::NoCapture)) {
> +            F.addAttribute(1, Attribute::NoCapture);
> +            ++NumAnnotated;
> +            Modified = true;
> +          }
> +          if (!F.paramHasAttr(2, Attribute::NoCapture)) {
> +            F.addAttribute(2, Attribute::NoCapture);
> +            ++NumAnnotated;
> +            Modified = true;
> +          }

It would be much better to just call:

   SetFunctionAttribute(F, Attribute::DoesNotThrow);
   SetParamAttribute(F, 0, Attribute::NoCapture);
   SetParamAttribute(F, 1, Attribute::NoCapture);

And have the "set*attribute" helper method handle the checking to see  
if the attribute already exists, the bumping of numannotated and  
setting of Modified.

-Chris