diff --git a/src/cmd/compile/internal/ssa/block.go b/src/cmd/compile/internal/ssa/block.go
index 4a24a181e5..26af10b59c 100644
--- a/src/cmd/compile/internal/ssa/block.go
+++ b/src/cmd/compile/internal/ssa/block.go
@@ -297,6 +297,8 @@ func (b *Block) removePred(i int) {
 // removeSucc removes the ith output edge from b.
 // It is the responsibility of the caller to remove
 // the corresponding predecessor edge.
+// Note that this potentially reorders successors of b, so it
+// must be used very carefully.
 func (b *Block) removeSucc(i int) {
 	n := len(b.Succs) - 1
 	if i != n {
@@ -323,6 +325,19 @@ func (b *Block) swapSuccessors() {
 	b.Likely *= -1
 }
 
+// Swaps b.Succs[x] and b.Succs[y].
+func (b *Block) swapSuccessorsByIdx(x, y int) {
+	if x == y {
+		return
+	}
+	ex := b.Succs[x]
+	ey := b.Succs[y]
+	b.Succs[x] = ey
+	b.Succs[y] = ex
+	ex.b.Preds[ex.i].i = y
+	ey.b.Preds[ey.i].i = x
+}
+
 // removePhiArg removes the ith arg from phi.
 // It must be called after calling b.removePred(i) to
 // adjust the corresponding phi value of the block:
@@ -339,7 +354,7 @@ func (b *Block) swapSuccessors() {
 func (b *Block) removePhiArg(phi *Value, i int) {
 	n := len(b.Preds)
 	if numPhiArgs := len(phi.Args); numPhiArgs-1 != n {
-		b.Fatalf("inconsistent state, num predecessors: %d, num phi args: %d", n, numPhiArgs)
+		b.Fatalf("inconsistent state for %v, num predecessors: %d, num phi args: %d", phi, n, numPhiArgs)
 	}
 	phi.Args[i].Uses--
 	phi.Args[i] = phi.Args[n]
diff --git a/src/cmd/compile/internal/ssa/deadcode.go b/src/cmd/compile/internal/ssa/deadcode.go
index ae9fd2ef24..3bd1737bab 100644
--- a/src/cmd/compile/internal/ssa/deadcode.go
+++ b/src/cmd/compile/internal/ssa/deadcode.go
@@ -312,6 +312,8 @@ func deadcode(f *Func) {
 
 // removeEdge removes the i'th outgoing edge from b (and
 // the corresponding incoming edge from b.Succs[i].b).
+// Note that this potentially reorders successors of b, so it
+// must be used very carefully.
 func (b *Block) removeEdge(i int) {
 	e := b.Succs[i]
 	c := e.b
diff --git a/src/cmd/compile/internal/ssa/sccp.go b/src/cmd/compile/internal/ssa/sccp.go
index 3c109548ab..86c6117d87 100644
--- a/src/cmd/compile/internal/ssa/sccp.go
+++ b/src/cmd/compile/internal/ssa/sccp.go
@@ -533,12 +533,12 @@ func rewireSuccessor(block *Block, constVal *Value) bool {
 		block.ResetControls()
 		return true
 	case BlockJumpTable:
+		// Remove everything but the known taken branch.
 		idx := int(constVal.AuxInt)
-		targetBlock := block.Succs[idx].b
-		for len(block.Succs) > 0 {
-			block.removeEdge(0)
+		block.swapSuccessorsByIdx(0, idx)
+		for len(block.Succs) > 1 {
+			block.removeEdge(1)
 		}
-		block.AddEdgeTo(targetBlock)
 		block.Kind = BlockPlain
 		block.Likely = BranchUnknown
 		block.ResetControls()
diff --git a/test/fixedbugs/issue64606.go b/test/fixedbugs/issue64606.go
new file mode 100644
index 0000000000..9b53c1041f
--- /dev/null
+++ b/test/fixedbugs/issue64606.go
@@ -0,0 +1,32 @@
+// build -race
+
+//go:build race
+
+// Copyright 2023 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.
+
+package main
+
+func main() {
+	var o any = uint64(5)
+	switch o.(type) {
+	case int:
+		goto ret
+	case int8:
+		goto ret
+	case int16:
+		goto ret
+	case int32:
+		goto ret
+	case int64:
+		goto ret
+	case float32:
+		goto ret
+	case float64:
+		goto ret
+	default:
+		goto ret
+	}
+ret:
+}