diff --git a/clang/lib/Driver/ToolChains/Hexagon.cpp b/clang/lib/Driver/ToolChains/Hexagon.cpp
--- a/clang/lib/Driver/ToolChains/Hexagon.cpp
+++ b/clang/lib/Driver/ToolChains/Hexagon.cpp
@@ -588,21 +588,38 @@
 
 void HexagonToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
                                                  ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdinc) ||
-      DriverArgs.hasArg(options::OPT_nostdlibinc))
+  if (DriverArgs.hasArg(options::OPT_nostdinc))
     return;
 
   const Driver &D = getDriver();
-  if (!D.SysRoot.empty()) {
+  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;
+
+  const bool HasSysRoot = !D.SysRoot.empty();
+  if (HasSysRoot) {
     SmallString<128> P(D.SysRoot);
     if (getTriple().isMusl())
       llvm::sys::path::append(P, "usr/include");
     else
       llvm::sys::path::append(P, "include");
+
     addExternCSystemInclude(DriverArgs, CC1Args, P.str());
-    return;
+    // LOCAL_INCLUDE_DIR
+    addSystemInclude(DriverArgs, CC1Args, P + "/usr/local/include");
+    // TOOL_INCLUDE_DIR
+    AddMultilibIncludeArgs(DriverArgs, CC1Args);
   }
 
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc) && getTriple().isMusl())
+    addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
+
+  if (HasSysRoot)
+    return;
   std::string TargetDir = getHexagonTargetDir(D.getInstalledDir(),
                                               D.PrefixDirs);
   addExternCSystemInclude(DriverArgs, CC1Args, TargetDir + "/hexagon/include");