From df7b3af19444e1863e54a419984a5d07d86cd8eb Mon Sep 17 00:00:00 2001
From: Lai-YT <381xvmvbib@gmail.com>
Date: Mon, 10 Jun 2024 16:34:19 +0800
Subject: [PATCH] Generate code for comma operator

---
 src/qbe_ir_generator.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/qbe_ir_generator.cpp b/src/qbe_ir_generator.cpp
index a3bad939..bd348bb7 100644
--- a/src/qbe_ir_generator.cpp
+++ b/src/qbe_ir_generator.cpp
@@ -862,6 +862,17 @@ void QbeIrGenerator::Visit(const UnaryExprNode& unary_expr) {
 
 void QbeIrGenerator::Visit(const BinaryExprNode& bin_expr) {
   bin_expr.lhs->Accept(*this);
+
+  if (bin_expr.op == BinaryOperator::kComma) {
+    // For the comma operator, the value of its left operand is not used and can
+    // be eliminated if it has no side effects or if its definition is
+    // immediately dead. However, we leave these optimizations to QBE.
+    bin_expr.rhs->Accept(*this);
+    const int right_num = num_recorder.NumOfPrevExpr();
+    num_recorder.Record(right_num);
+    return;
+  }
+
   const int left_num = num_recorder.NumOfPrevExpr();
   // Due to the lack of direct support for logical operators in QBE, we
   // implement logical expressions using comparison and jump instructions.