[clang] [llvm] [AMDGPU] Match bitsin(typeof(x)) - popcnt(x) to s_bcnt0_i32 (PR #164847)

[Patrick Simmons via llvm-commits]

linuxrocks123 wrote:

@arsenm okay, comments dealt with.  If you'd like to preserve the global isel error, I should revert or partially revert the last commit.  Otherwise, LGTM?

https://github.com/llvm/llvm-project/pull/164847