From a2eca8fe1f83ddfc2043f6136331668bfb039aa5 Mon Sep 17 00:00:00 2001
From: Roberto Raggi <roberto.raggi@gmail.com>
Date: Wed, 30 Jul 2025 22:32:49 +0200
Subject: [PATCH] Generate MLIR code for the simple assignments

---
 src/mlir/cxx/mlir/codegen.h              |  9 +++++++-
 src/mlir/cxx/mlir/codegen_expressions.cc | 27 +++++++++++++++++++++---
 src/mlir/cxx/mlir/codegen_statements.cc  |  2 +-
 3 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/src/mlir/cxx/mlir/codegen.h b/src/mlir/cxx/mlir/codegen.h
index 7f8fead8..ef0feafb 100644
--- a/src/mlir/cxx/mlir/codegen.h
+++ b/src/mlir/cxx/mlir/codegen.h
@@ -112,7 +112,14 @@ class Codegen {
 
   void statement(StatementAST* ast);
 
-  [[nodiscard]] auto expression(ExpressionAST* ast) -> ExpressionResult;
+  enum struct ExpressionFormat {
+    kValue,
+    kSideEffect,
+  };
+
+  [[nodiscard]] auto expression(
+      ExpressionAST* ast, ExpressionFormat format = ExpressionFormat::kValue)
+      -> ExpressionResult;
 
   [[nodiscard]] auto templateParameter(TemplateParameterAST* ast)
       -> TemplateParameterResult;
diff --git a/src/mlir/cxx/mlir/codegen_expressions.cc b/src/mlir/cxx/mlir/codegen_expressions.cc
index a741c24c..4b49b1da 100644
--- a/src/mlir/cxx/mlir/codegen_expressions.cc
+++ b/src/mlir/cxx/mlir/codegen_expressions.cc
@@ -31,6 +31,7 @@ namespace cxx {
 
 struct Codegen::ExpressionVisitor {
   Codegen& gen;
+  ExpressionFormat format = ExpressionFormat::kValue;
 
   auto operator()(GeneratedLiteralExpressionAST* ast) -> ExpressionResult;
   auto operator()(CharLiteralExpressionAST* ast) -> ExpressionResult;
@@ -104,8 +105,9 @@ struct Codegen::NewInitializerVisitor {
   auto operator()(NewBracedInitializerAST* ast) -> NewInitializerResult;
 };
 
-auto Codegen::expression(ExpressionAST* ast) -> ExpressionResult {
-  if (ast) return visit(ExpressionVisitor{*this}, ast);
+auto Codegen::expression(ExpressionAST* ast, ExpressionFormat format)
+    -> ExpressionResult {
+  if (ast) return visit(ExpressionVisitor{*this, format}, ast);
   return {};
 }
 
@@ -252,7 +254,7 @@ auto Codegen::ExpressionVisitor::operator()(NestedStatementExpressionAST* ast)
 
 auto Codegen::ExpressionVisitor::operator()(NestedExpressionAST* ast)
     -> ExpressionResult {
-  return gen.expression(ast->expression);
+  return gen.expression(ast->expression, format);
 }
 
 auto Codegen::ExpressionVisitor::operator()(IdExpressionAST* ast)
@@ -865,6 +867,25 @@ auto Codegen::ExpressionVisitor::operator()(ThrowExpressionAST* ast)
 
 auto Codegen::ExpressionVisitor::operator()(AssignmentExpressionAST* ast)
     -> ExpressionResult {
+  if (ast->op == TokenKind::T_EQUAL) {
+    auto leftExpressionResult = gen.expression(ast->leftExpression);
+    auto rightExpressionResult = gen.expression(ast->rightExpression);
+
+    // Generate a store operation
+    auto loc = gen.getLocation(ast->opLoc);
+
+    auto resultType = gen.convertType(ast->leftExpression->type);
+
+    gen.builder_.create<mlir::cxx::StoreOp>(loc, rightExpressionResult.value,
+                                            leftExpressionResult.value);
+
+    if (format == ExpressionFormat::kSideEffect) {
+      return {};
+    }
+
+    return leftExpressionResult;
+  }
+
   auto op =
       gen.emitTodoExpr(ast->firstSourceLocation(), to_string(ast->kind()));
 
diff --git a/src/mlir/cxx/mlir/codegen_statements.cc b/src/mlir/cxx/mlir/codegen_statements.cc
index 7d8600b4..0f192390 100644
--- a/src/mlir/cxx/mlir/codegen_statements.cc
+++ b/src/mlir/cxx/mlir/codegen_statements.cc
@@ -107,7 +107,7 @@ void Codegen::StatementVisitor::operator()(DefaultStatementAST* ast) {
 }
 
 void Codegen::StatementVisitor::operator()(ExpressionStatementAST* ast) {
-  auto expressionResult = gen.expression(ast->expression);
+  (void)gen.expression(ast->expression, ExpressionFormat::kSideEffect);
 }
 
 void Codegen::StatementVisitor::operator()(CompoundStatementAST* ast) {