diff --git a/src/cmd/compile/internal/ssa/prove.go b/src/cmd/compile/internal/ssa/prove.go
index ec31d46d02..cf0118ac3c 100644
--- a/src/cmd/compile/internal/ssa/prove.go
+++ b/src/cmd/compile/internal/ssa/prove.go
@@ -193,6 +193,15 @@ func (ft *factsTable) update(parent *Block, v, w *Value, d domain, r relation) {
 		return
 	}
 
+	// Self-fact. It's wasteful to register it into the facts
+	// table, so just note whether it's satisfiable
+	if v == w {
+		if r&eq == 0 {
+			ft.unsat = true
+		}
+		return
+	}
+
 	if lessByID(w, v) {
 		v, w = w, v
 		r = reverseBits[r]