diff --git a/test/run.go b/test/run.go
index 85dc51d1dd..76babdfae8 100644
--- a/test/run.go
+++ b/test/run.go
@@ -459,7 +459,7 @@ func init() { checkShouldTest() }
 // or else the commands will rebuild any needed packages (like runtime)
 // over and over.
 func goGcflags() string {
-	return "-gcflags=" + os.Getenv("GO_GCFLAGS")
+	return "-gcflags=all=" + os.Getenv("GO_GCFLAGS")
 }
 
 // run runs a test.