[cc] comment fixes

Author: jgarzik

cc/ir/linearize.rs

@@ -1091,7 +1091,7 @@ impl<'a> Linearizer<'a> {
                         if let Some(func) = &mut self.current_func {
                             func.add_pseudo(high_pseudo);
                         }
-                        // Always load 8 bytes for the high part - codegen will handle alignment
+                        // Load up to 8 bytes for the high part (may be less for structs < 16 bytes)
                         let high_size = std::cmp::min(64, struct_size - 64);
                         self.emit(Instruction::load(
                             high_temp,

cc/tests/datatypes/struct_type.rs

@@ -320,10 +320,10 @@ int main(void) {
 #[test]
 fn struct_return_two_register() {
     let code = r#"
-// 12-byte struct - uses two-register return (RAX+RDX or X0+X1)
+// 16-byte struct (12 bytes data + 4 bytes padding) - uses two-register return (RAX+RDX or X0+X1)
 struct medium {
     long first;   // 8 bytes
-    int second;   // 4 bytes (+ 4 padding = 16 total with alignment)
+    int second;   // 4 bytes (+ 4 bytes padding for alignment; total 16 bytes)
 };
 
 struct medium make_medium(long a, int b) {