diff options
| author | Benjamin Kramer <benny.kra@googlemail.com> | 2011-01-15 20:30:30 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2011-01-15 20:30:30 +0000 |
| commit | b6516aeef12a05aa47515f76e18fc426d85babbd (patch) | |
| tree | 673d40370dbf9d6dfec81d45a5fbe5543185b99b /lib/Support/Path.cpp | |
| parent | 248f9f280756a1d6eb20a97ee4ab457ec18170f6 (diff) | |
| download | llvm-b6516aeef12a05aa47515f76e18fc426d85babbd.tar.gz llvm-b6516aeef12a05aa47515f76e18fc426d85babbd.tar.bz2 llvm-b6516aeef12a05aa47515f76e18fc426d85babbd.tar.xz | |
Reimplement CTPOP legalization with the "best" algorithm from
http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
In a silly microbenchmark on a 65 nm core2 this is 1.5x faster than the old
code in 32 bit mode and about 2x faster in 64 bit mode. It's also a lot shorter,
especially when counting 64 bit population on a 32 bit target.
I hope this is fast enough to replace Kernighan-style counting loops even when
the input is rather sparse.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123547 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Support/Path.cpp')
0 files changed, 0 insertions, 0 deletions