diff --git a/src/cmd/go/internal/work/security.go b/src/cmd/go/internal/work/security.go
index d02630155b..0ce1664c16 100644
--- a/src/cmd/go/internal/work/security.go
+++ b/src/cmd/go/internal/work/security.go
@@ -52,7 +52,7 @@ var validCompilerFlags = []*lazyregexp.Regexp{
 	re(`-W([^@,]+)`), // -Wall but not -Wa,-foo.
 	re(`-Wa,-mbig-obj`),
 	re(`-Wp,-D([A-Za-z_].*)`),
-	re(`-Wp, -U([A-Za-z_]*)`),
+	re(`-Wp,-U([A-Za-z_]*)`),
 	re(`-ansi`),
 	re(`-f(no-)?asynchronous-unwind-tables`),
 	re(`-f(no-)?blocks`),
diff --git a/src/cmd/go/internal/work/security_test.go b/src/cmd/go/internal/work/security_test.go
index 3a02db1d04..6b85c40b13 100644
--- a/src/cmd/go/internal/work/security_test.go
+++ b/src/cmd/go/internal/work/security_test.go
@@ -22,6 +22,8 @@ var goodCompilerFlags = [][]string{
 	{"-Osmall"},
 	{"-W"},
 	{"-Wall"},
+	{"-Wp,-Dfoo=bar"},
+	{"-Wp,-Ufoo"},
 	{"-fobjc-arc"},
 	{"-fno-objc-arc"},
 	{"-fomit-frame-pointer"},