Author: serge-sans-paille Date: 2021-03-01T10:18:36+01:00 New Revision: 80e8efd563fda4d7b125b834d3243b3ef9a05270
URL: https://github.com/llvm/llvm-project/commit/80e8efd563fda4d7b125b834d3243b3ef9a05270 DIFF: https://github.com/llvm/llvm-project/commit/80e8efd563fda4d7b125b834d3243b3ef9a05270.diff LOG: Use a fast path when initializing LineOffsetMapping Use the fact that the number of line break is lower than printable characters to guide the optimization process. Also use a fuzzy test that catches both \n and \r in a single check to speedup the computation. Differential Revision: https://reviews.llvm.org/D97320 Added: Modified: clang/lib/Basic/SourceManager.cpp Removed: ################################################################################ diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp index c0b22837693b..cc275d4e8dc4 100644 --- a/clang/lib/Basic/SourceManager.cpp +++ b/clang/lib/Basic/SourceManager.cpp @@ -1270,13 +1270,16 @@ LineOffsetMapping LineOffsetMapping::get(llvm::MemoryBufferRef Buffer, const std::size_t BufLen = End - Buf; unsigned I = 0; while (I < BufLen) { - if (Buf[I] == '\n') { - LineOffsets.push_back(I + 1); - } else if (Buf[I] == '\r') { - // If this is \r\n, skip both characters. - if (I + 1 < BufLen && Buf[I + 1] == '\n') - ++I; - LineOffsets.push_back(I + 1); + // Use a fast check to catch both newlines + if (LLVM_UNLIKELY(Buf[I] <= std::max('\n', '\r'))) { + if (Buf[I] == '\n') { + LineOffsets.push_back(I + 1); + } else if (Buf[I] == '\r') { + // If this is \r\n, skip both characters. + if (I + 1 < BufLen && Buf[I + 1] == '\n') + ++I; + LineOffsets.push_back(I + 1); + } } ++I; } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
