diff --git a/src/cmd/compile/internal/ssa/shortcircuit.go b/src/cmd/compile/internal/ssa/shortcircuit.go
index 7b4ee2e81c..c72c86a67e 100644
--- a/src/cmd/compile/internal/ssa/shortcircuit.go
+++ b/src/cmd/compile/internal/ssa/shortcircuit.go
@@ -266,6 +266,13 @@ func shortcircuitPhiPlan(b *Block, ctl *Value, cidx int, ti int64) func(*Value,
 	// u is the "untaken" branch: the successor we never go to when coming in from p.
 	u := b.Succs[1^ti].b
 
+	// In the following CFG matching, ensure that b's preds are entirely distinct from b's succs.
+	// This is probably a stronger condition than required, but this happens extremely rarely,
+	// and it makes it easier to avoid getting deceived by pretty ASCII charts. See #44465.
+	if p0, p1 := b.Preds[0].b, b.Preds[1].b; p0 == t || p1 == t || p0 == u || p1 == u {
+		return nil
+	}
+
 	// Look for some common CFG structures
 	// in which the outbound paths from b merge,
 	// with no other preds joining them.
diff --git a/test/fixedbugs/issue44465.go b/test/fixedbugs/issue44465.go
new file mode 100644
index 0000000000..8cb62adaac
--- /dev/null
+++ b/test/fixedbugs/issue44465.go
@@ -0,0 +1,21 @@
+// compile -d=ssa/check/seed
+
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This code caused an internal consistency error due to a bad shortcircuit optimization.
+
+package p
+
+func f() {
+	var b bool
+	if b {
+		b = true
+	}
+l:
+	for !b {
+		b = true
+		goto l
+	}
+}