Index: cfe/trunk/lib/Driver/ToolChains/Linux.cpp
===================================================================
--- cfe/trunk/lib/Driver/ToolChains/Linux.cpp
+++ cfe/trunk/lib/Driver/ToolChains/Linux.cpp
@@ -658,11 +658,11 @@
   if (!DriverArgs.hasArg(options::OPT_nostdlibinc))
     addSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/local/include");
 
-  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
-    SmallString<128> P(D.ResourceDir);
-    llvm::sys::path::append(P, "include");
-    addSystemInclude(DriverArgs, CC1Args, P);
-  }
+  SmallString<128> ResourceDirInclude(D.ResourceDir);
+  llvm::sys::path::append(ResourceDirInclude, "include");
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc) &&
+      (!getTriple().isMusl() || DriverArgs.hasArg(options::OPT_nostdlibinc)))
+    addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
 
   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
     return;
@@ -860,6 +860,9 @@
   addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/include");
 
   addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
+
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc) && getTriple().isMusl())
+    addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
 }
 
 static std::string DetectLibcxxIncludePath(llvm::vfs::FileSystem &vfs,
Index: cfe/trunk/test/Driver/linux-musl-header-search.cpp
===================================================================
--- cfe/trunk/test/Driver/linux-musl-header-search.cpp
+++ cfe/trunk/test/Driver/linux-musl-header-search.cpp
@@ -0,0 +1,39 @@
+// RUN: %clang -no-canonical-prefixes %s -### -fsyntax-only 2>&1 \
+// RUN:     -target x86_64-linux-musl -stdlib=libc++ \
+// RUN:     -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
+// RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree --gcc-toolchain= \
+// RUN:   | FileCheck --check-prefix=CHECK-X86-64-LIBCXX %s
+
+// RESOURCE_DIR/include comes after /usr/include on linux-musl.
+// This is different from a glibc-based distribution.
+// CHECK-X86-64-LIBCXX: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-X86-64-LIBCXX: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-X86-64-LIBCXX: "-internal-isystem" "[[SYSROOT]]/usr/include/c++/v1"
+// CHECK-X86-64-LIBCXX: "-internal-isystem" "[[SYSROOT]]/usr/local/include"
+// CHECK-X86-64-LIBCXX: "-internal-externc-isystem" "[[SYSROOT]]/usr/include"
+// CHECK-X86-64-LIBCXX: "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
+
+// RUN: %clang -no-canonical-prefixes %s -### -fsyntax-only -nobuiltininc 2>&1 \
+// RUN:     -target x86_64-linux-musl \
+// RUN:     -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
+// RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree --gcc-toolchain= \
+// RUN:   | FileCheck --check-prefix=CHECK-NOBUILTININC %s
+
+// CHECK-NOBUILTININC: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-NOBUILTININC-NOT: "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
+
+// RUN: %clang -no-canonical-prefixes %s -### -fsyntax-only -nostdlibinc 2>&1 \
+// RUN:     -target x86_64-linux-musl \
+// RUN:     -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
+// RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree --gcc-toolchain= \
+// RUN:   | FileCheck --check-prefix=CHECK-NOSTDLIBINC %s
+
+// CHECK-NOSTDLIBINC: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-NOSTDLIBINC-NOT: "-internal-externc-isystem"
+// CHECK-NOSTDLIBINC-NOT: "-internal-isystem"
+// CHECK-NOSTDLIBINC: "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
+// CHECK-NOSTDLIBINC-NOT: "-internal-externc-isystem"
+// CHECK-NOSTDLIBINC-NOT: "-internal-isystem"