From c64bce3eb8a6f5e9d4873f3ce3b3e16ad5e614cb Mon Sep 17 00:00:00 2001
From: Eduard Urbach <eduard@urbach.dev>
Date: Mon, 15 Jun 2026 18:46:51 +0200
Subject: [PATCH] Fixed missing register assignment when returning a comparison

---
 src/codegen/conditionalSet.go  | 23 +++++++++++++++++++++++
 src/codegen/executeBinaryOp.go |  4 ++++
 src/codegen/executeUnaryOp.go  | 19 ++++---------------
 src/codegen/hintDestination.go |  2 ++
 src/ssa/UnaryOp.go             |  2 +-
 tests/return-bool.q            | 32 ++++++++++++++++++++++++++++++++
 tests/tests_test.go            |  1 +
 7 files changed, 67 insertions(+), 16 deletions(-)
 create mode 100644 src/codegen/conditionalSet.go
 create mode 100644 tests/return-bool.q

diff --git a/src/codegen/conditionalSet.go b/src/codegen/conditionalSet.go
new file mode 100644
index 0000000..69df801
--- /dev/null
+++ b/src/codegen/conditionalSet.go
@@ -0,0 +1,23 @@
+package codegen
+
+import (
+	"git.urbach.dev/cli/q/src/asm"
+	"git.urbach.dev/cli/q/src/config"
+	"git.urbach.dev/cli/q/src/cpu"
+	"git.urbach.dev/cli/q/src/token"
+)
+
+// conditionalSet sets the target register to 0 or 1 depending on the condition.
+func (f *Function) conditionalSet(register cpu.Register, condition token.Kind) {
+	if f.build.Arch == config.X86 {
+		f.Assembler.Append(&asm.MoveNumber{
+			Destination: register,
+			Number:      0,
+		})
+	}
+
+	f.Assembler.Append(&asm.ConditionalSet{
+		Destination: register,
+		Condition:   condition,
+	})
+}
\ No newline at end of file
diff --git a/src/codegen/executeBinaryOp.go b/src/codegen/executeBinaryOp.go
index 297736a..a372698 100644
--- a/src/codegen/executeBinaryOp.go
+++ b/src/codegen/executeBinaryOp.go
@@ -20,6 +20,10 @@ func (f *Function) executeBinaryOp(step *Step, instr *ssa.BinaryOp) {
 			f.Assembler.Append(&asm.Compare{Destination: left.Register, Source: right.Register})
 		}
 
+		if step.Register != -1 {
+			f.conditionalSet(step.Register, instr.Op)
+		}
+
 		return
 	}
 
diff --git a/src/codegen/executeUnaryOp.go b/src/codegen/executeUnaryOp.go
index d15f3ef..c966e45 100644
--- a/src/codegen/executeUnaryOp.go
+++ b/src/codegen/executeUnaryOp.go
@@ -2,38 +2,27 @@ package codegen
 
 import (
 	"git.urbach.dev/cli/q/src/asm"
-	"git.urbach.dev/cli/q/src/config"
 	"git.urbach.dev/cli/q/src/ssa"
 	"git.urbach.dev/cli/q/src/token"
 )
 
 func (f *Function) executeUnaryOp(step *Step, instr *ssa.UnaryOp) {
-	left := f.ValueToStep[instr.Operand]
+	operand := f.ValueToStep[instr.Operand]
 
 	switch instr.Op {
 	case token.Negate:
 		f.Assembler.Append(&asm.Negate{
 			Destination: step.Register,
-			Source:      left.Register,
+			Source:      operand.Register,
 		})
 
 	case token.Not:
 		f.Assembler.Append(&asm.CompareNumber{
-			Destination: left.Register,
+			Destination: operand.Register,
 			Number:      0,
 		})
 
-		if f.build.Arch == config.X86 {
-			f.Assembler.Append(&asm.MoveNumber{
-				Destination: step.Register,
-				Number:      0,
-			})
-		}
-
-		f.Assembler.Append(&asm.ConditionalSet{
-			Destination: step.Register,
-			Condition:   token.Equal,
-		})
+		f.conditionalSet(step.Register, token.Equal)
 
 	default:
 		panic("not implemented: " + instr.String())
diff --git a/src/codegen/hintDestination.go b/src/codegen/hintDestination.go
index 8020b59..443903d 100644
--- a/src/codegen/hintDestination.go
+++ b/src/codegen/hintDestination.go
@@ -27,5 +27,7 @@ func (f *Function) hintDestination(step *Step) {
 			variant.Phis.Add(step)
 			variant.hint(step.Register)
 		}
+	case *ssa.UnaryOp:
+		f.ValueToStep[instr.Operand].hint(step.Register)
 	}
 }
\ No newline at end of file
diff --git a/src/ssa/UnaryOp.go b/src/ssa/UnaryOp.go
index 30c37f8..903a71c 100644
--- a/src/ssa/UnaryOp.go
+++ b/src/ssa/UnaryOp.go
@@ -45,7 +45,7 @@ func (u *UnaryOp) Replace(old Value, new Value) {
 
 // String returns a human-readable representation of the unary operation.
 func (u *UnaryOp) String() string {
-	return fmt.Sprintf("%s(%s)", u.Op, u.Operand)
+	return fmt.Sprintf("%s(%p)", u.Op, u.Operand)
 }
 
 // Type returns the type of the operand.
diff --git a/tests/return-bool.q b/tests/return-bool.q
new file mode 100644
index 0000000..e4cc417
--- /dev/null
+++ b/tests/return-bool.q
@@ -0,0 +1,32 @@
+main() {
+	assert no() == false
+	assert yes() == true
+	assert notNo() == true
+	assert notYes() == false
+	assert notNotNo() == false
+	assert notNotYes() == true
+}
+
+no() -> bool {
+	return 1 < 0
+}
+
+yes() -> bool {
+	return 1 > 0
+}
+
+notNo() -> bool {
+	return !(1 < 0)
+}
+
+notYes() -> bool {
+	return !(1 > 0)
+}
+
+notNotNo() -> bool {
+	return !!(1 < 0)
+}
+
+notNotYes() -> bool {
+	return !!(1 > 0)
+}
\ No newline at end of file
diff --git a/tests/tests_test.go b/tests/tests_test.go
index 061e652..3e0c729 100644
--- a/tests/tests_test.go
+++ b/tests/tests_test.go
@@ -104,6 +104,7 @@ var tests = []run{
 	{"return-2", nil, "", "", 0},
 	{"return-3", nil, "", "", 0},
 	{"return-4", nil, "", "", 0},
+	{"return-bool", nil, "", "", 0},
 	{"return-string", nil, "", "Hello\n", 0},
 	{"return-tuple", nil, "", "", 0},
 	{"multi-define-assign", nil, "", "", 0},
-- 
2.51.2