[llvm] [aarch64][win] Add support for import call optimization (equivalent to MSVC /d2ImportCallOptimization) (PR #121516)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

> I have some numbers: when applied to the Arm64 Windows Kernel, we saw a 3% throughput improvement on DiskSpd benchmarks for both SnapDragon 8cx Gen2 and Gen3 devices.

Interesting - that's a massive number a change like this. I'm not too familiar with the structure of the kernel though, I presume that there would need to be a huge number of cross-DLL function calls within the kernel for this change to make any measurable difference.

https://github.com/llvm/llvm-project/pull/121516