fix set_n pass

rust2/benches/loopremove.bf

@@ -1,4 +0,0 @@
->+++++[-]++++++++++[[-->+++++++++>+++++++++>+++++++++<<<<->]]>.>.>.
-<[-]<[-]<[-]
->>>>+ >>>>> ++++++++++ <<<< <<<<<
-+[[>>>>]]+[[++--[+++>>]]>.][-]

rust2/benches/opts.rs

@@ -32,14 +32,12 @@ fn run_bf(bf: &str) {
 fn optimized(c: &mut Criterion) {
     let fizzbuzz = include_str!("fizzbuzz.bf");
     let bench = include_str!("bench.bf");
-    let loopremove = include_str!("loopremove.bf");
     let twinkle = include_str!("twinkle.bf");
     let bottles = include_str!("bottles.bf");
     let hanoi = include_str!("hanoi.bf");
 
     c.bench_function("fizzbuzz", |b| b.iter(|| run_bf(black_box(fizzbuzz))));
     c.bench_function("bench", |b| b.iter(|| run_bf(black_box(bench))));
-    c.bench_function("loopremove", |b| b.iter(|| run_bf(black_box(loopremove))));
     c.bench_function("twinkle", |b| b.iter(|| run_bf(black_box(twinkle))));
     c.bench_function("bottles", |b| b.iter(|| run_bf(black_box(bottles))));
     c.bench_function("hanoi", |b| b.iter(|| run_bf(black_box(hanoi))));

rust2/src/opts.rs

@@ -154,8 +154,16 @@ fn pass_find_set_null(ir: &mut Ir<'_>) {
 /// pass that replaces `SetNull Add(5)` with `SetN(5)`
 fn pass_set_n(ir: &mut Ir<'_>) {
     let stmts = &mut ir.stmts;
-    let mut i = 0;
-    while i < stmts.len() - 1 {
+    for i in 0..stmts.len() {
+        let a = &mut stmts[i];
+        if let StmtKind::Loop(body) = &mut a.kind {
+            pass_set_n(body);
+        }
+
+        if i >= stmts.len() - 1 {
+            break; // we are the last element
+        }
+
         let a = &stmts[i];
         if let StmtKind::SetNull = a.kind() {
             let b = &stmts[i + 1];
@@ -163,7 +171,6 @@ fn pass_set_n(ir: &mut Ir<'_>) {
                 StmtKind::Add(n) => StmtKind::SetN(*n),
                 StmtKind::Sub(n) => StmtKind::SetN(0u8.wrapping_sub(*n)),
                 _ => {
-                    i += 1;
                     continue;
                 }
             };
@@ -171,6 +178,5 @@ fn pass_set_n(ir: &mut Ir<'_>) {
             stmts.remove(i + 1);
             stmts[i] = Stmt::new(new, span);
         }
-        i += 1;
     }
 }

rust2/test.bf

@@ -1 +1 @@
-++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.
+[>[-]+++++++++++++++++++++++++[>[-]++++++[-]<-]<-]