From 97cf7348edbb5f102b1bb6dddd0084b155be85d0 Mon Sep 17 00:00:00 2001
From: Ajay Brahmakshatriya <ajaybr@mit.edu>
Date: Mon, 20 May 2024 17:05:32 -0400
Subject: [PATCH] Fixed bug in RCE

---
 include/builder/operator_overload.h |  8 ++++----
 samples/outputs.var_names/sample42  |  1 +
 samples/outputs.var_names/sample57  |  6 ++++++
 samples/outputs/sample42            |  1 +
 samples/outputs/sample57            |  6 ++++++
 samples/sample42.cpp                |  2 ++
 samples/sample57.cpp                | 31 +++++++++++++++++++++++++++++
 src/blocks/rce.cpp                  | 10 ++++++++++
 8 files changed, 61 insertions(+), 4 deletions(-)
 create mode 100644 samples/outputs.var_names/sample57
 create mode 100644 samples/outputs/sample57
 create mode 100644 samples/sample57.cpp

diff --git a/include/builder/operator_overload.h b/include/builder/operator_overload.h
index ede7a3b..dea9877 100644
--- a/include/builder/operator_overload.h
+++ b/include/builder/operator_overload.h
@@ -156,22 +156,22 @@ typename return_type_helper<T>::type operator&(const T &a) {
 
 // Prefix increment
 template <typename T>
-typename return_type_helper<T>::type operator++(T &a) {
+typename return_type_helper<typename std::remove_reference<T>::type>::type operator++(T &&a) {
 	return (a = a + 1);
 }
 // Postfix increment
 template <typename T>
-typename return_type_helper<T>::type operator++(T &a, int) {
+typename return_type_helper<typename std::remove_reference<T>::type>::type operator++(T &&a, int) {
 	return ((a = a + 1) - 1);
 }
 // Prefix decrement
 template <typename T>
-typename return_type_helper<T>::type operator--(T &a) {
+typename return_type_helper<typename std::remove_reference<T>::type>::type operator--(T &&a) {
 	return (a = a - 1);
 }
 // Postfix increment
 template <typename T>
-typename return_type_helper<T>::type operator--(T &a, int) {
+typename return_type_helper<typename std::remove_reference<T>::type>::type operator--(T &&a, int) {
 	return ((a = a - 1) + 1);
 }
 
diff --git a/samples/outputs.var_names/sample42 b/samples/outputs.var_names/sample42
index 5eee6ef..2b51296 100644
--- a/samples/outputs.var_names/sample42
+++ b/samples/outputs.var_names/sample42
@@ -8,5 +8,6 @@ void bar (void) {
     y_0[0] = y_0[0] - x_2;
     y_0[x_2] = y_0[x_2] / 2;
   }
+  (y_0[0] = y_0[0] + 1) - 1;
 }
 
diff --git a/samples/outputs.var_names/sample57 b/samples/outputs.var_names/sample57
new file mode 100644
index 0000000..182253d
--- /dev/null
+++ b/samples/outputs.var_names/sample57
@@ -0,0 +1,6 @@
+void bar (void) {
+  int x_0 = 0;
+  int* y_1 = (&(x_0));
+  (y_1[0] = y_1[0] + 1) - 1;
+}
+
diff --git a/samples/outputs/sample42 b/samples/outputs/sample42
index f438a06..5f3dd65 100644
--- a/samples/outputs/sample42
+++ b/samples/outputs/sample42
@@ -8,5 +8,6 @@ void bar (void) {
     var0[0] = var0[0] - var2;
     var0[var2] = var0[var2] / 2;
   }
+  (var0[0] = var0[0] + 1) - 1;
 }
 
diff --git a/samples/outputs/sample57 b/samples/outputs/sample57
new file mode 100644
index 0000000..62b48df
--- /dev/null
+++ b/samples/outputs/sample57
@@ -0,0 +1,6 @@
+void bar (void) {
+  int var0 = 0;
+  int* var1 = (&(var0));
+  (var1[0] = var1[0] + 1) - 1;
+}
+
diff --git a/samples/sample42.cpp b/samples/sample42.cpp
index 97df989..6e85991 100644
--- a/samples/sample42.cpp
+++ b/samples/sample42.cpp
@@ -20,6 +20,8 @@ static void bar(void) {
 		*y -= x;
 		y[x] /= 2;
 	}
+
+	(*y)++;
 }
 
 int main(int argc, char *argv[]) {
diff --git a/samples/sample57.cpp b/samples/sample57.cpp
new file mode 100644
index 0000000..05f11eb
--- /dev/null
+++ b/samples/sample57.cpp
@@ -0,0 +1,31 @@
+// Include the headers
+#include "blocks/c_code_generator.h"
+#include "builder/static_var.h"
+#include "builder/dyn_var.h"
+#include "blocks/rce.h"
+#include <iostream>
+
+// Include the BuildIt types
+using builder::dyn_var;
+using builder::static_var;
+
+static void bar(void) {
+     // Insert code to stage here
+    
+    dyn_var<int> x = 0;
+    dyn_var<int*> y = &x;
+    
+    (*y)++;
+     
+     
+}
+
+int main(int argc, char* argv[]) {
+	builder::builder_context context;
+	auto ast = context.extract_function_ast(bar, "bar");
+	block::eliminate_redundant_vars(ast);
+	block::c_code_generator::generate_code(ast, std::cout, 0);
+	return 0;
+}
+
+
diff --git a/src/blocks/rce.cpp b/src/blocks/rce.cpp
index 93f80c9..ab3a0e4 100644
--- a/src/blocks/rce.cpp
+++ b/src/blocks/rce.cpp
@@ -30,6 +30,16 @@ class var_use_counter : public block_visitor {
 		if (std::find(assigned_vars.begin(), assigned_vars.end(), v) == assigned_vars.end())
 			assigned_vars.push_back(v);
 	}
+	virtual void visit(addr_of_expr::Ptr e) override {
+		e->expr1->accept(this);
+		if (!isa<var_expr>(e->expr1))
+			return;
+		var_expr::Ptr ve = to<var_expr>(e->expr1);
+		var::Ptr v = ve->var1;
+		// Variables that have their addresses taken can potentially be assigned and hence should not be copy eliminated
+		if (std::find(assigned_vars.begin(), assigned_vars.end(), v) == assigned_vars.end())
+			assigned_vars.push_back(v);
+	}
 };
 
 class check_side_effects : public block_visitor {