Fix comparing two unsigned types (#488)

self_hosted/create_llvm_ir.jou

@@ -276,7 +276,7 @@ class AstToIR:
             assert False
 
         if lhs_type->is_integer_type() and rhs_type->is_integer_type():
-            is_signed = lhs_type->kind == TypeKind::SignedInteger and rhs_type->kind == TypeKind::SignedInteger
+            is_signed = lhs_type->kind == TypeKind::SignedInteger or rhs_type->kind == TypeKind::SignedInteger
             if op == AstExpressionKind::Add:
                 return LLVMBuildAdd(self->builder, lhs, rhs, "add")
             if op == AstExpressionKind::Subtract:

src/codegen.c

@@ -392,11 +392,11 @@ static void codegen_instruction(const struct State *st, const CfInstruction *ins
                 setdest(LLVMBuildFCmp(st->builder, LLVMRealOEQ, getop(0), getop(1), "num_eq"));
             break;
         case CF_NUM_LT:
-            if (is_integer_type(ins->operands[0]->type))
-                // TODO: unsigned less than
+            if (ins->operands[0]->type->kind == TYPE_UNSIGNED_INTEGER && ins->operands[1]->type->kind == TYPE_UNSIGNED_INTEGER)
+                setdest(LLVMBuildICmp(st->builder, LLVMIntULT, getop(0), getop(1), "num_lt"));
+            else if (is_integer_type(ins->operands[0]->type) && is_integer_type(ins->operands[1]->type))
                 setdest(LLVMBuildICmp(st->builder, LLVMIntSLT, getop(0), getop(1), "num_lt"));
             else
-                // TODO: signed less than
                 setdest(LLVMBuildFCmp(st->builder, LLVMRealOLT, getop(0), getop(1), "num_lt"));
             break;
     }

tests/should_succeed/compare_bytes.jou

@@ -0,0 +1,20 @@
+import "stdlib/io.jou"
+
+
+# TODO: It's not possible to test things like "signed < unsigned" yet with types of the same size.
+# For 8-bit there's only unsigned (byte), for 16-bit only signed (short), 32-bit only signed (int), 64-bit only signed (long).
+def main() -> int:
+    a = 0 as byte
+    b = 100 as byte
+    c = 200 as byte
+
+    printf("%d %d %d\n", a < b, b < b, c < b)       # Output: 1 0 0
+    printf("%d %d %d\n", a > b, b > b, c > b)       # Output: 0 0 1
+
+    printf("%d %d %d\n", a <= b, b <= b, c <= b)    # Output: 1 1 0
+    printf("%d %d %d\n", a >= b, b >= b, c >= b)    # Output: 0 1 1
+
+    printf("%d %d %d\n", a == b, b == b, c == b)    # Output: 0 1 0
+    printf("%d %d %d\n", a != b, b != b, c != b)    # Output: 1 0 1
+
+    return 0