diff --git a/js/src/moz.build b/js/src/moz.build
index 1162cb70c1..0a4abd80f3 100644
--- a/js/src/moz.build
+++ b/js/src/moz.build
@@ -785,7 +785,9 @@ if CONFIG['JS_HAS_CTYPES']:
         DEFINES['FFI_BUILDING'] = True
 
 if CONFIG['GNU_CXX']:
-    CXXFLAGS += ['-Wno-shadow', '-Werror=format']
+    # Disable strict-aliasing for GCC, which is enabled by default
+    # starting with version 7.1, see Mozilla bug 1363009.
+    CXXFLAGS += ['-Wno-shadow', '-Werror=format', '-fno-strict-aliasing']
 
 # Suppress warnings in third-party code.
 if CONFIG['CLANG_CXX']: