diff --git a/llvm/.gitattributes b/llvm/.gitattributes
--- a/llvm/.gitattributes
+++ b/llvm/.gitattributes
@@ -25,3 +25,5 @@
 test/tools/llvm-strings/radix.test text eol=lf
 test/tools/split-file/basic.test text eol=lf
 test/tools/split-file/Inputs/basic-*.txt eol=lf
+test/tools/split-file/basic.crlf.test text eol=crlf
+test/tools/split-file/Inputs/basic-*.crlf eol=crlf
diff --git a/llvm/test/tools/split-file/Inputs/basic-aa.crlf b/llvm/test/tools/split-file/Inputs/basic-aa.crlf
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/split-file/Inputs/basic-aa.crlf
@@ -0,0 +1,2 @@
+
+aa
diff --git a/llvm/test/tools/split-file/Inputs/basic-bb.crlf b/llvm/test/tools/split-file/Inputs/basic-bb.crlf
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/split-file/Inputs/basic-bb.crlf
@@ -0,0 +1,6 @@
+
+
+
+; Comments are preserved.
+bb
+
diff --git a/llvm/test/tools/split-file/Inputs/basic-cc.crlf b/llvm/test/tools/split-file/Inputs/basic-cc.crlf
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/split-file/Inputs/basic-cc.crlf
@@ -0,0 +1,8 @@
+
+
+
+
+
+
+
+cc
diff --git a/llvm/test/tools/split-file/basic.crlf.test b/llvm/test/tools/split-file/basic.crlf.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/split-file/basic.crlf.test
@@ -0,0 +1,40 @@
+#--- aa
+aa
+;--- bb
+; Comments are preserved.
+bb
+
+//--- subdir/cc
+cc
+//--- end
+
+# RUN: rm -rf %t
+# RUN: split-file --leading-lines %s %t
+# RUN: diff %S/Inputs/basic-aa.crlf %t/aa
+# RUN: diff %S/Inputs/basic-bb.crlf %t/bb
+# RUN: diff %S/Inputs/basic-cc.crlf %t/subdir/cc
+# RUN: FileCheck %s --check-prefix=END < %t/end
+
+## Can be called on a non-empty directory.
+# RUN: split-file --leading-lines %s %t
+# RUN: diff %S/Inputs/basic-aa.crlf %t/aa
+
+## Test that we will delete the output if it is a file, so that we can create
+## a directory.
+# RUN: rm -rf %t && touch %t
+# RUN: split-file --leading-lines %s %t
+# RUN: diff %S/Inputs/basic-aa.crlf %t/aa
+
+# END: RUN: split-file %s %t
+
+# RUN: not %split-file 2>&1 | FileCheck %s --check-prefix=NO_INPUT
+
+# NO_INPUT: split-file: error: input filename is not specified
+
+# RUN: not %split-file %s '' 2>&1 | FileCheck %s --check-prefix=NO_OUTPUT
+
+# NO_OUTPUT: split-file: error: output directory is not specified
+
+# RUN: not %split-file %S/Inputs/basic-aa.crlf %t 2>&1 | FileCheck %s --check-prefix=NOT_EXIST
+
+# NOT_EXIST: split-file: error: {{.*}}: no part separator was found
diff --git a/llvm/tools/split-file/split-file.cpp b/llvm/tools/split-file/split-file.cpp
--- a/llvm/tools/split-file/split-file.cpp
+++ b/llvm/tools/split-file/split-file.cpp
@@ -71,6 +71,7 @@
 static int handle(MemoryBuffer &inputBuf, StringRef input) {
   DenseMap<StringRef, Part> partToBegin;
   StringRef lastPart, separator;
+  StringRef EOL = inputBuf.getBuffer().detectEOL();
   for (line_iterator i(inputBuf, /*SkipBlanks=*/false, '\0'); !i.is_at_eof();) {
     const int64_t lineNo = i.line_number();
     const StringRef line = *i++;
@@ -128,7 +129,7 @@
 
     Part &part = keyValue.second;
     for (int64_t i = 0; i != part.leadingLines; ++i)
-      (*f).os().write('\n');
+      (*f).os() << EOL;
     if (part.begin)
       (*f).os().write(part.begin, part.end - part.begin);
     outputFiles.push_back(std::move(f));