[LLVMdev] _Znwm is not a builtin

[Howard Hinnant]

On May 15, 2013, at 11:59 PM, Chandler Carruth <chandlerc at google.com> wrote:

> 
> On Wed, May 15, 2013 at 9:46 PM, Chris Lattner <clattner at apple.com> wrote:
> It's not clear to me that "builtin" is the right way to model this, but it definitely sounds like this should be an attribute on a call site (as opposed to on the function itself).  What specific kinds of optimizations are we interested in doing to _Znwm calls?
> 
> You can see the paper to the C++ committee, but my primary goals.
> 
> 1) run SROA over heap memory
> 2) pool together heap allocations on the same CFG trace
> 3) promote (sufficiently small and lifetime bounded) heap allocations to stack allocations

This appears to me to be an observable change (with custom new/delete).  Will this optimization be limited to -std=c++1y?

Howard