diff --git a/tools/v8_gypfiles/v8.gyp b/tools/v8_gypfiles/v8.gyp
index 381803e9855..eb0ecea0168 100644
--- a/tools/v8_gypfiles/v8.gyp
+++ b/tools/v8_gypfiles/v8.gyp
@@ -504,6 +504,9 @@
           ],
         }],
         ['OS in "aix os400"', {
+          'variables': {
+            'FP16_ROOT': '../../deps/v8/third_party/fp16',
+          },
           'include_dirs': [
             '<(FP16_ROOT)/src/include',
           ],