diff --git a/src/cmd/compile/internal/base/debug.go b/src/cmd/compile/internal/base/debug.go
index fd42021946..e2245e1c26 100644
--- a/src/cmd/compile/internal/base/debug.go
+++ b/src/cmd/compile/internal/base/debug.go
@@ -48,6 +48,7 @@ type DebugFlags struct {
 	TypeAssert           int    `help:"print information about type assertion inlining"`
 	TypecheckInl         int    `help:"eager typechecking of inline function bodies"`
 	Unified              int    `help:"enable unified IR construction"`
+	UnifiedQuirks        int    `help:"enable unified IR construction's quirks mode"`
 	WB                   int    `help:"print information about write barriers"`
 	ABIWrap              int    `help:"print information about ABI wrapper generation"`
 
diff --git a/src/cmd/compile/internal/noder/quirks.go b/src/cmd/compile/internal/noder/quirks.go
index 28a729f276..91b4c22025 100644
--- a/src/cmd/compile/internal/noder/quirks.go
+++ b/src/cmd/compile/internal/noder/quirks.go
@@ -23,10 +23,7 @@ import (
 // quirksMode controls whether behavior specific to satisfying
 // toolstash -cmp is used.
 func quirksMode() bool {
-	// Currently, unified IR doesn't try to be compatible with
-	// -d=inlfuncswithclosures=1, so we overload this as a flag for
-	// enabling quirks mode.
-	return base.Debug.InlFuncsWithClosures == 0
+	return base.Debug.UnifiedQuirks != 0
 }
 
 // posBasesOf returns all of the position bases in the source files,
diff --git a/src/cmd/compile/internal/noder/unified_test.go b/src/cmd/compile/internal/noder/unified_test.go
index 242fa1282f..4732892f6c 100644
--- a/src/cmd/compile/internal/noder/unified_test.go
+++ b/src/cmd/compile/internal/noder/unified_test.go
@@ -59,7 +59,7 @@ func TestUnifiedCompare(t *testing.T) {
 			}
 
 			pkgs1 := loadPackages(t, goos, goarch, "-d=unified=0 -d=inlfuncswithclosures=0")
-			pkgs2 := loadPackages(t, goos, goarch, "-d=unified=1 -d=inlfuncswithclosures=0")
+			pkgs2 := loadPackages(t, goos, goarch, "-d=unified=1 -d=inlfuncswithclosures=0 -d=unifiedquirks=1")
 
 			if len(pkgs1) != len(pkgs2) {
 				t.Fatalf("length mismatch: %v != %v", len(pkgs1), len(pkgs2))