LLVMCodeBuilder: Fix list type change before last write in loop

Author: adazem009

src/engine/internal/llvm/llvmcodebuilder.cpp

@@ -2356,7 +2356,7 @@ bool LLVMCodeBuilder::isVarOrListTypeSafe(std::shared_ptr<LLVMInstruction> ins,
     // Find previous write instruction in this, parent or child loop scope
     size_t index = it - instructions.begin();
 
-    if (index > 0) {
+    if (varPtr && index > 0) { // this is only needed for variables
         bool found = false;
 
         do {
@@ -2401,7 +2401,7 @@ bool LLVMCodeBuilder::isVarOrListTypeSafe(std::shared_ptr<LLVMInstruction> ins,
         checkScope = checkScope->parentScope;
     }
 
-    // Find n-th last write operation based on counter (may be in a parent or child scope)
+    // Get all write operations in all loop scopes (from the root loop scope)
     std::vector<std::shared_ptr<LLVMInstruction>> lastWrites;
 
     while (checkScope) {
@@ -2425,15 +2425,26 @@ bool LLVMCodeBuilder::isVarOrListTypeSafe(std::shared_ptr<LLVMInstruction> ins,
     if (c >= lastWrites.size())
         return true;
 
-    write = lastWrites[lastWrites.size() - c - 1]; // Ignore last c writes
+    if (varPtr)
+        write = lastWrites[lastWrites.size() - c - 1]; // Ignore last c writes
+    else {
+        // If this is a list instruction, check last write operations except current
+        for (long i = lastWrites.size() - c - 1; i >= 0; i--) { // Ignore last c writes
+            if (lastWrites[i] == ins)
+                continue;
+
+            if (!isVarOrListWriteResultTypeSafe(lastWrites[i], expectedType, false, log, c))
+                return false;
+        }
+    }
 
     bool safe = true;
 
     if (VAR_LIST_READ_INSTRUCTIONS.find(ins->type) == VAR_LIST_READ_INSTRUCTIONS.cend()) // write
         safe = isVarOrListWriteResultTypeSafe(ins, expectedType, false, log, c);
 
     if (safe)
-        return isVarOrListWriteResultTypeSafe(write, expectedType, false, log, c);
+        return write ? isVarOrListWriteResultTypeSafe(write, expectedType, false, log, c) : true;
     else
         return false;
 }

test/llvm/llvmcodebuilder_test.cpp

@@ -5149,15 +5149,19 @@ TEST_F(LLVMCodeBuilderTest, ListLoopTypeAnalysis6)
 
     createBuilder(&sprite, true);
 
+    m_builder->createListClear(globalList.get());
     m_builder->createListClear(localList.get());
 
-    CompilerValue *v = m_builder->addConstValue(5.25);
+    CompilerValue *v = m_builder->addConstValue(-156.07);
+    m_builder->createListAppend(globalList.get(), v);
+
+    v = m_builder->addConstValue(5.25);
     m_builder->createListAppend(localList.get(), v);
 
     v = m_builder->addConstValue(2);
     m_builder->beginRepeatLoop(v);
     {
-        // Type is unknown here because a list item with unknown type is added later (even though the list item has the original type assigned, it cannot be determined at compile time)
+        // Type is unknown here because a list item with unknown type is added later
         v = m_builder->createSub(m_builder->addListSize(localList.get()), m_builder->addConstValue(1));
         v = m_builder->addListItem(localList.get(), v);
         m_builder->addFunctionCall("test_print_number", Compiler::StaticType::Void, { Compiler::StaticType::Number }, { v });
@@ -5174,7 +5178,8 @@ TEST_F(LLVMCodeBuilderTest, ListLoopTypeAnalysis6)
             v = m_builder->addConstValue(10);
             m_builder->createListReplace(globalList.get(), m_builder->addConstValue(0), v);
 
-            v = m_builder->addListItem(globalList.get(), m_builder->addConstValue(0));
+            v = m_builder->createSub(m_builder->addListSize(globalList.get()), m_builder->addConstValue(1));
+            v = m_builder->addListItem(globalList.get(), v);
             m_builder->createListAppend(localList.get(), v);
 
             v = m_builder->addConstValue("test");
@@ -5188,7 +5193,7 @@ TEST_F(LLVMCodeBuilderTest, ListLoopTypeAnalysis6)
         "5.25\n"
         "0\n"
         "1\n"
-        "10\n"
+        "0\n"
         "0\n"
         "1\n";