[llvm-branch-commits] [llvm] [LoongArch] Add memory barrier optimization pass (PR #218597)

[via llvm-branch-commits]

heiher wrote:

### Clang Built Linux 7.2

Linux kernel: v7.2
Base: 2be211bb2ab35461520530f37e3faf382dc644d5
Patch: #218597

The data below are static instruction counts collected from the disassembled vmlinux built with the default loongarch64 config.

| Inst Count      | Base  | Patch(default) | %       | Patch(loongarch-require-no-path-bypass=no) | %       |
|-----------------|-------|----------------|---------|--------------------------------------------|---------|
| DBAR            | 33161 | 29317          | -11.59% | 29236                                      | -11.83% |
| AMO(with DB)    | 6997  | 7528           | +7.58%  | 7525                                       | +7.54%  |
| AMO(without DB) | 11308 | 10777          | -4.69%  | 10780                                      | -4.66%  |

https://github.com/llvm/llvm-project/pull/218597