From 403e78f655d2a75502a99f3ccc933abc8781b3c7 Mon Sep 17 00:00:00 2001
From: Eduard Urbach <admin@akyoto.dev>
Date: Sun, 7 Jul 2024 14:07:34 +0200
Subject: [PATCH] Improved branch code generation

---
 examples/hello/hello.q      |  2 +-
 src/build/ast/Parse.go      | 14 +++++++-------
 src/build/core/CompileIf.go |  4 +++-
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/examples/hello/hello.q b/examples/hello/hello.q
index 53d906b..f6e8e26 100644
--- a/examples/hello/hello.q
+++ b/examples/hello/hello.q
@@ -1,7 +1,7 @@
 main() {
 	x := f(1) + f(2) + f(3)
 
-	if x != 9 {
+	if x != f(8) {
 		exit(42)
 	}
 
diff --git a/src/build/ast/Parse.go b/src/build/ast/Parse.go
index 4f00224..aa4eeef 100644
--- a/src/build/ast/Parse.go
+++ b/src/build/ast/Parse.go
@@ -33,7 +33,7 @@ func toASTNode(tokens token.List) (Node, error) {
 			return &Return{Value: value}, nil
 
 		case keyword.Loop:
-			blockStart := tokens.IndexKind(token.BlockStart) + 1
+			blockStart := tokens.IndexKind(token.BlockStart)
 			blockEnd := tokens.LastIndexKind(token.BlockEnd)
 
 			if blockStart == -1 {
@@ -44,11 +44,11 @@ func toASTNode(tokens token.List) (Node, error) {
 				return nil, errors.New(errors.MissingBlockEnd, nil, tokens[len(tokens)-1].End())
 			}
 
-			tree, err := Parse(tokens[blockStart:blockEnd])
-			return &Loop{Body: tree}, err
+			body, err := Parse(tokens[blockStart+1 : blockEnd])
+			return &Loop{Body: body}, err
 
 		case keyword.If:
-			blockStart := tokens.IndexKind(token.BlockStart) + 1
+			blockStart := tokens.IndexKind(token.BlockStart)
 			blockEnd := tokens.LastIndexKind(token.BlockEnd)
 
 			if blockStart == -1 {
@@ -59,9 +59,9 @@ func toASTNode(tokens token.List) (Node, error) {
 				return nil, errors.New(errors.MissingBlockEnd, nil, tokens[len(tokens)-1].End())
 			}
 
-			condition := expression.Parse(tokens[1:token.BlockStart])
-			tree, err := Parse(tokens[blockStart:blockEnd])
-			return &If{Condition: condition, Body: tree}, err
+			condition := expression.Parse(tokens[1:blockStart])
+			body, err := Parse(tokens[blockStart+1 : blockEnd])
+			return &If{Condition: condition, Body: body}, err
 
 		default:
 			return nil, errors.New(&errors.KeywordNotImplemented{Keyword: tokens[0].Text()}, nil, tokens[0].Position)
diff --git a/src/build/core/CompileIf.go b/src/build/core/CompileIf.go
index 2f058e3..a38c76f 100644
--- a/src/build/core/CompileIf.go
+++ b/src/build/core/CompileIf.go
@@ -10,13 +10,14 @@ import (
 // CompileIf compiles a branch instruction.
 func (f *Function) CompileIf(branch *ast.If) error {
 	condition := branch.Condition
-	tmpRight := f.cpu.Input[1]
+	tmpRight := f.cpu.MustFindFree(f.cpu.General)
 	err := f.ExpressionToRegister(condition.Children[1], tmpRight)
 
 	if err != nil {
 		return err
 	}
 
+	f.cpu.Use(tmpRight)
 	tmpLeft := f.cpu.Input[0]
 	err = f.ExpressionToRegister(condition.Children[0], tmpLeft)
 
@@ -25,6 +26,7 @@ func (f *Function) CompileIf(branch *ast.If) error {
 	}
 
 	f.assembler.RegisterRegister(asm.COMPARE, tmpLeft, tmpRight)
+	f.cpu.Free(tmpRight)
 	elseLabel := fmt.Sprintf("%s_if_%d_else", f.Name, f.count.branch)
 
 	switch condition.Token.Text() {