[Bug c/109734] New: ARM64 support for __builtin_popcountll

[rohan at garg dot io via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109734

            Bug ID: 109734
           Summary: ARM64 support for __builtin_popcountll
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rohan at garg dot io
  Target Milestone: ---

Hi
I noticed that ARM32 & ARM64 has native support for popcnt [1], but gcc only
outputs the native instruction for ARM32 [2].

I was hoping that someone could add native support for ARM64 too.

[1]
https://developer.arm.com/documentation/ddi0602/2022-12/Base-Instructions/CNT--Count-bits-?lang=en
[2] https://godbolt.org/z/aG8Mx4o6W