// PR15642
-// RUN: %clang -M -MG %s | FileCheck -strict-whitespace %s
+// RUN: %clang -M -MG -fno-ms-compatibility %s | FileCheck -strict-whitespace %s --check-prefix=CHECK --check-prefix=SEP2F
+// RUN: %clang -M -MG -fms-compatibility %s | FileCheck -strict-whitespace %s --check-prefix=CHECK --check-prefix=SEP5C
// RUN: %clang -M -MG -MV %s | FileCheck -strict-whitespace %s --check-prefix=NMAKE
// CHECK: \ \ \ \ .h
// Backslash followed by # or space should escape both characters, because
// that's what GNU Make wants. GCC does the right thing with space, but not
// #, so Clang does too. (There should be 3 backslashes before the #.)
-// CHECK: a\b\\#c\\\ d.h
+// SEP2F: a\b\\#c\\\ d.h
+// With -fms-compatibility, Backslashes in #include are treated as path separators.
+// Backslashes are given in the emission for special characters, like 0x20 or 0x23.
+// SEP5C: a{{[/\\]}}b{{[/\\]}}\#c{{[/\\]}}\ d.h
// These combinations are just another case for NMAKE.
-// NMAKE: "a\b\#c\ d.h"
+// NMAKE: "a{{[/\\]}}b{{[/\\]}}#c{{[/\\]}} d.h"
#include "a\b\#c\ d.h"