--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1501,17 +1501,6 @@ if (use_blink && !is_cronet_build) {
 # While linux-x86 is unsupported, chromeos-x86 is not, and since ChromeOS uses
 # the linux sysroot (and thus linux modulemaps), generating chromeos-x86
 # modulemaps requires building targets on linux-x86
-if (!running_modularize) {
-  # TODO(cassew): Add more OS's that don't support x86.
-  is_valid_x86_target =
-      target_os != "ios" && target_os != "mac" &&
-      (target_os != "linux" || use_libfuzzer || !build_with_chromium)
-
-  # Note: v8_target_cpu == arm allows using the V8 arm simulator on x86 for fuzzing.
-  assert(
-      is_valid_x86_target || target_cpu != "x86" || v8_target_cpu == "arm",
-      "'target_cpu=x86' is not supported for 'target_os=$target_os'. Consider omitting 'target_cpu' (default) or using 'target_cpu=x64' instead.")
-}
 
 group("chromium_builder_perf") {
   testonly = true