diff --git a/src/codegen/clobberedRegisters.go b/src/codegen/clobberedRegisters.go
index 9773b96..b9c0c20 100644
--- a/src/codegen/clobberedRegisters.go
+++ b/src/codegen/clobberedRegisters.go
@@ -7,8 +7,8 @@ import (
 )
 
 // clobberedRegisters returns the registers that are clobbered by the given instruction.
-func (f *Function) clobberedRegisters(instr ssa.Value) []cpu.Register {
-	switch instr := instr.(type) {
+func (f *Function) clobberedRegisters(step *Step) []cpu.Register {
+	switch instr := step.Value.(type) {
 	case *ssa.BinaryOp:
 		switch instr.Op {
 		case token.Div, token.Mod:
@@ -18,6 +18,8 @@ func (f *Function) clobberedRegisters(instr ssa.Value) []cpu.Register {
 		default:
 			return nil
 		}
+	case *ssa.Branch, *ssa.Jump:
+		return phiMoveClobbered(step)
 	case *ssa.Call:
 		return f.CPU.Call.Clobbered
 	case *ssa.CallExtern:
diff --git a/src/codegen/findFreeRegister.go b/src/codegen/findFreeRegister.go
index ef9dc37..d26131d 100644
--- a/src/codegen/findFreeRegister.go
+++ b/src/codegen/findFreeRegister.go
@@ -117,7 +117,7 @@ func (f *Function) findFreeRegister(step *Step) cpu.Register {
 
 		// Find all the registers that this instruction
 		// would clobber and mark them as used.
-		for _, reg := range f.clobberedRegisters(current.Value) {
+		for _, reg := range f.clobberedRegisters(current) {
 			usedRegisters.Set(reg)
 		}
 	}
@@ -146,4 +146,4 @@ func (f *Function) findFreeRegister(step *Step) cpu.Register {
 	}
 
 	panic("no free registers")
-}
+}
\ No newline at end of file
diff --git a/src/codegen/fixRegisterConflicts.go b/src/codegen/fixRegisterConflicts.go
index 1d1c7c1..9fb566c 100644
--- a/src/codegen/fixRegisterConflicts.go
+++ b/src/codegen/fixRegisterConflicts.go
@@ -40,7 +40,7 @@ func (f *Function) fixRegisterConflicts() {
 			}
 		}
 
-		clobbered := f.clobberedRegisters(step.Value)
+		clobbered := f.clobberedRegisters(step)
 
 		for i, live := range step.Live {
 			if live.Register == -1 {
diff --git a/src/codegen/insertPhiMoves.go b/src/codegen/insertPhiMoves.go
index a257444..a87753d 100644
--- a/src/codegen/insertPhiMoves.go
+++ b/src/codegen/insertPhiMoves.go
@@ -20,6 +20,10 @@ func (f *Function) insertPhiMoves(step *Step) {
 
 	for _, live := range step.Live {
 		for phi := range live.Phis.All() {
+			if live.Register == phi.Register {
+				continue
+			}
+
 			predecessors := phi.Block.Predecessors
 
 			if !slices.Contains(predecessors, step.Block) {
diff --git a/src/codegen/phiMoveClobbered.go b/src/codegen/phiMoveClobbered.go
new file mode 100644
index 0000000..65edc1c
--- /dev/null
+++ b/src/codegen/phiMoveClobbered.go
@@ -0,0 +1,32 @@
+package codegen
+
+import (
+	"slices"
+
+	"git.urbach.dev/cli/q/src/cpu"
+)
+
+// phiMoveClobbered returns the destinations of phi moves.
+func phiMoveClobbered(step *Step) []cpu.Register {
+	var clobbered []cpu.Register
+
+	for _, live := range step.Live {
+		for phi := range live.Phis.All() {
+			if live.Register == phi.Register {
+				continue
+			}
+
+			if slices.Contains(clobbered, phi.Register) {
+				continue
+			}
+
+			if !slices.Contains(phi.Block.Predecessors, step.Block) {
+				continue
+			}
+
+			clobbered = append(clobbered, phi.Register)
+		}
+	}
+
+	return clobbered
+}
\ No newline at end of file
diff --git a/tests/phi-reassign-copy.q b/tests/phi-reassign-copy.q
new file mode 100644
index 0000000..c7ee621
--- /dev/null
+++ b/tests/phi-reassign-copy.q
@@ -0,0 +1,11 @@
+main() {
+	a := 4
+	b := 8
+	c := 7
+
+	if a != b {
+		c = a
+	}
+
+	assert c == 4
+}
\ No newline at end of file
diff --git a/tests/tests_test.go b/tests/tests_test.go
index 1572cd2..6b13913 100644
--- a/tests/tests_test.go
+++ b/tests/tests_test.go
@@ -56,6 +56,7 @@ var tests = []run{
 	{"phi-advanced", nil, "", "", 0},
 	{"phi-reassign", nil, "", "", 0},
 	{"phi-reassign-output", nil, "", "12345", 0},
+	{"phi-reassign-copy", nil, "", "", 0},
 	{"phi-move-cycle", nil, "", "0\n14\n0\n", 0},
 	{"phi-move-reorder", nil, "", "0\n14\n0\n", 0},
 	{"min", nil, "", "", 0},