diff --git a/openmp/runtime/src/CMakeLists.txt b/openmp/runtime/src/CMakeLists.txt
--- a/openmp/runtime/src/CMakeLists.txt
+++ b/openmp/runtime/src/CMakeLists.txt
@@ -220,6 +220,28 @@
     WORKING_DIRECTORY ${LIBOMP_LIBRARY_DIR}
   )
 endif()
+# Copy headers to clang build directory structure
+# so it can find & use them before install
+if (NOT OPENMP_STANDALONE_BUILD AND (LLVM_TOOL_CLANG_BUILD OR LLVM_RUNTIMES_BUILD))
+  function(copy_header_to_output_dir src dst_name)
+    # Had to manually copy this since CLANG_VERSION may be empty
+    set(major "${LLVM_VERSION_MAJOR}")
+    set(minor "${LLVM_VERSION_MINOR}")
+    set(patch "${LLVM_VERSION_PATCH}")
+    set(output_dir ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${major}.${minor}.${patch}/include)
+    set(dst ${output_dir}/${dst_name})
+    add_custom_command(TARGET omp POST_BUILD
+      DEPENDS ${src}
+      COMMAND ${CMAKE_COMMAND} -E copy_if_different ${src} ${dst}
+      COMMENT "Copying OpenMP header ${dst_name}...")
+  endfunction(copy_header_to_output_dir)
+  copy_header_to_output_dir(${CMAKE_CURRENT_BINARY_DIR}/omp.h omp.h)
+  if(LIBOMP_OMPT_SUPPORT)
+    copy_header_to_output_dir(${CMAKE_CURRENT_BINARY_DIR}/omp-tools.h omp-tools.h)
+    copy_header_to_output_dir(${CMAKE_CURRENT_BINARY_DIR}/omp-tools.h ompt.h)
+  endif()
+endif()
+
 set(LIBOMP_INCLUDE_DIR ${CMAKE_CURRENT_BINARY_DIR} PARENT_SCOPE)
 
 # Create *.inc before compiling any sources