[LLVMdev] _Znwm is not a builtin

Howard Hinnant hhinnant at apple.com
Thu May 16 10:40:03 PDT 2013

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?


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