Author: Louis Dionne Date: 2020-12-01T12:49:45-05:00 New Revision: c30d5101f14f7e8a1c0f80c8663b54de2a7640fd
URL: https://github.com/llvm/llvm-project/commit/c30d5101f14f7e8a1c0f80c8663b54de2a7640fd DIFF: https://github.com/llvm/llvm-project/commit/c30d5101f14f7e8a1c0f80c8663b54de2a7640fd.diff LOG: [libc++] Optimize the number of assignments in std::exclusive_scan Reported in https://twitter.com/blelbach/status/1169807347142676480 Differential Revision: https://reviews.llvm.org/D67273 Added: Modified: libcxx/include/numeric Removed: ################################################################################ diff --git a/libcxx/include/numeric b/libcxx/include/numeric index 5c10dd3c1e67..ed06fcc49d5b 100644 --- a/libcxx/include/numeric +++ b/libcxx/include/numeric @@ -335,14 +335,17 @@ exclusive_scan(_InputIterator __first, _InputIterator __last, { if (__first != __last) { - _Tp __saved = __init; - do + _Tp __tmp(__b(__init, *__first)); + while (true) { - __init = __b(__init, *__first); - *__result = __saved; - __saved = __init; + *__result = _VSTD::move(__init); ++__result; - } while (++__first != __last); + ++__first; + if (__first == __last) + break; + __init = _VSTD::move(__tmp); + __tmp = __b(__init, *__first); + } } return __result; } _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
