feat: add constant folding and dead code elimination passes

src/main.rs

@@ -5,6 +5,8 @@ use clap::Parser as ClapParser;
 use crate::frontend::parser::Parser;
 use crate::frontend::sema::Sema;
 use crate::middle::builder::MirBuilder;
+use crate::middle::dce::eliminate_dead_code;
+use crate::middle::fold::fold_constants;
 
 pub mod backend;
 pub mod frontend;
@@ -57,7 +59,13 @@ fn main() {
         exit(1);
     }
 
-    let mir_module = MirBuilder::build(&typed_module);
+    let mut mir_module = MirBuilder::build(&typed_module);
+    fold_constants(&mut mir_module);
+    let warnings = eliminate_dead_code(&mut mir_module);
+
+    for warning in warnings {
+        eprintln!("Warning: {} at {:?}", warning.message, warning.span);
+    }
 
     let backend = CraneliftBackend::new();
     let (ir, obj_bytes) = backend.compile_module(&mir_module);