Check for trivial expressions that they are >0 when unsigned

reid-llvm-lib/src/builder.rs

@@ -395,8 +395,6 @@ impl Builder {
                 Instr::Alloca(_) => Ok(()),
                 Instr::Load(ptr, load_ty) => {
                     let ptr_ty = ptr.get_type(&self)?;
-                    dbg!(&self);
-                    dbg!(&ptr_ty, &load_ty);
                     if let Type::Ptr(ptr_ty_inner) = ptr_ty {
                         if *ptr_ty_inner == load_ty {
                             Ok(())

reid/src/mir/implement.rs

@@ -29,6 +29,30 @@ impl TypeKind {
         }
     }
 
+    pub fn signed(&self) -> bool {
+        match self {
+            TypeKind::Bool => false,
+            TypeKind::I8 => true,
+            TypeKind::I16 => true,
+            TypeKind::I32 => true,
+            TypeKind::I64 => true,
+            TypeKind::I128 => true,
+            TypeKind::U8 => false,
+            TypeKind::U16 => false,
+            TypeKind::U32 => false,
+            TypeKind::U64 => false,
+            TypeKind::U128 => false,
+            TypeKind::Void => false,
+            TypeKind::StringPtr => false,
+            TypeKind::Array(type_kind, len) => false,
+            TypeKind::CustomType(_) => false,
+            TypeKind::CodegenPtr(_) => false,
+            TypeKind::Vague(_) => false,
+            TypeKind::Borrow(_, _) => false,
+            TypeKind::UserPtr(_) => false,
+        }
+    }
+
     pub fn size_of(&self) -> u64 {
         match self {
             TypeKind::Bool => 1,
@@ -262,6 +286,33 @@ impl Expression {
             ExprKind::If(_) => None,
         }
     }
+
+    pub fn is_zero(&self) -> Option<bool> {
+        Some(self.num_value()? == 0)
+    }
+
+    pub fn num_value(&self) -> Option<i128> {
+        match &self.0 {
+            ExprKind::Variable(_) => None,
+            ExprKind::Indexed(..) => None,
+            ExprKind::Accessed(..) => None,
+            ExprKind::Array(_) => None,
+            ExprKind::Struct(..) => None,
+            ExprKind::Literal(literal) => literal.num_value(),
+            ExprKind::BinOp(op, lhs, rhs) => match op {
+                BinaryOperator::Add => Some(lhs.num_value()? + rhs.num_value()?),
+                BinaryOperator::Minus => Some(lhs.num_value()? - rhs.num_value()?),
+                BinaryOperator::Mult => Some(lhs.num_value()? * rhs.num_value()?),
+                BinaryOperator::And => None,
+                BinaryOperator::Cmp(_) => None,
+            },
+            ExprKind::FunctionCall(..) => None,
+            ExprKind::If(_) => None,
+            ExprKind::Block(_) => None,
+            ExprKind::Borrow(_, _) => None,
+            ExprKind::Deref(_) => None,
+        }
+    }
 }
 
 impl IfExpression {
@@ -407,6 +458,26 @@ impl Collapsable for TypeKind {
     }
 }
 
+impl Literal {
+    pub fn num_value(&self) -> Option<i128> {
+        match self {
+            Literal::I8(val) => Some(*val as i128),
+            Literal::I16(val) => Some(*val as i128),
+            Literal::I32(val) => Some(*val as i128),
+            Literal::I64(val) => Some(*val as i128),
+            Literal::I128(val) => Some(*val as i128),
+            Literal::U8(val) => Some(*val as i128),
+            Literal::U16(val) => Some(*val as i128),
+            Literal::U32(val) => Some(*val as i128),
+            Literal::U64(val) => Some(*val as i128),
+            Literal::U128(val) => Some(*val as i128),
+            Literal::Bool(_) => None,
+            Literal::String(_) => None,
+            Literal::Vague(VagueLiteral::Number(val)) => Some(*val as i128),
+        }
+    }
+}
+
 impl Collapsable for ScopeFunction {
     fn collapse_into(&self, other: &ScopeFunction) -> Result<ScopeFunction, ErrorKind> {
         Ok(ScopeFunction {

reid/src/mir/linker.rs

@@ -103,10 +103,10 @@ impl<'map> Pass for LinkerPass<'map> {
             modules.insert(module.name.clone(), Rc::new(RefCell::new((module, tokens))));
         }
 
-        modules.insert(
-            "std".to_owned(),
-            Rc::new(RefCell::new(compile_std(&mut self.module_map)?)),
-        );
+        // modules.insert(
+        //     "std".to_owned(),
+        //     Rc::new(RefCell::new(compile_std(&mut self.module_map)?)),
+        // );
 
         let mut modules_to_process: Vec<Rc<RefCell<(Module, Vec<FullToken>)>>> =
             modules.values().cloned().collect();

reid/src/mir/mod.rs

@@ -183,7 +183,7 @@ impl VagueLiteral {
     }
 }
 
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub enum BinaryOperator {
     Add,
     Minus,
@@ -193,7 +193,7 @@ pub enum BinaryOperator {
 }
 
 /// Specifically the operators that LLVM likes to take in as "icmp" parameters
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub enum CmpOperator {
     LT,
     LE,

reid/src/mir/typecheck.rs

@@ -65,6 +65,8 @@ pub enum ErrorKind {
     ImpossibleMutableBorrow(String),
     #[error("Cannot declare variable {0} as mutable, when it's type is immutable")]
     ImpossibleMutLet(String),
+    #[error("Cannot produce a negative unsigned value of type {0}!")]
+    NegativeUnsignedValue(TypeKind),
 }
 
 /// Struct used to implement a type-checking pass that can be performed on the
@@ -409,6 +411,16 @@ impl Expression {
                 }
 
                 let both_t = lhs_type.collapse_into(&rhs_type)?;
+
+                dbg!(&op, &both_t, both_t.signed(), lhs.is_zero(), rhs.is_zero());
+                if *op == BinaryOperator::Minus && !lhs_type.signed() {
+                    if let (Some(lhs_val), Some(rhs_val)) = (lhs.num_value(), rhs.num_value()) {
+                        if lhs_val < rhs_val {
+                            return Err(ErrorKind::NegativeUnsignedValue(lhs_type));
+                        }
+                    }
+                }
+
                 Ok(both_t.binop_type(op))
             }
             ExprKind::FunctionCall(function_call) => {

reid_src/arithmetic.reid

@@ -5,5 +5,5 @@ fn main() -> u32 {
   let value = 6;
   let other = 15;
 
-  return value * other + 7 * (-value);
+  return value * other + 7 * -value;
 }