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
@@ -540,6 +540,13 @@
     return;
 
   const Driver &D = getDriver();
+  if (!D.SysRoot.empty()) {
+    SmallString<128> P(D.SysRoot);
+    llvm::sys::path::append(P, "include");
+    addExternCSystemInclude(DriverArgs, CC1Args, P.str());
+    return;
+  }
+
   std::string TargetDir = getHexagonTargetDir(D.getInstalledDir(),
                                               D.PrefixDirs);
   addExternCSystemInclude(DriverArgs, CC1Args, TargetDir + "/hexagon/include");
diff --git a/clang/test/Driver/hexagon-toolchain-elf.c b/clang/test/Driver/hexagon-toolchain-elf.c
--- a/clang/test/Driver/hexagon-toolchain-elf.c
+++ b/clang/test/Driver/hexagon-toolchain-elf.c
@@ -577,3 +577,14 @@
 // RUN:   | FileCheck -check-prefix=CHECK082 %s
 // CHECK082-NOT:      -march=
 // CHECK082-NOT:      -mcpu=
+// -----------------------------------------------------------------------------
+// Passing --sysroot
+// -----------------------------------------------------------------------------
+// RUN: %clang -### -target hexagon-unknown-elf \
+// RUN:   -ccc-install-dir %S/Inputs/hexagon_tree/Tools/bin \
+// RUN:   -mcpu=hexagonv60 \
+// RUN:   --sysroot=/hexagon \
+// RUN:   %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK083 %s
+// CHECK083:          "-isysroot" "/hexagon"
+// CHECK083:          "-internal-externc-isystem" "/hexagon/include"