add pass_add_sub_offset

rust2/src/codegen.rs

@@ -27,6 +27,8 @@ use std::fmt::{Debug, Formatter};
 pub enum Stmt {
     Add(u8),
     Sub(u8),
+    AddOffset(i32, u8),
+    SubOffset(i32, u8),
     Right(u32),
     Left(u32),
     Out,
@@ -86,6 +88,8 @@ fn ir_to_stmt<'c>(code: &mut Code<'c>, ir_stmt: &IrStmt<'_>) {
     let stmt = match &ir_stmt.kind {
         StmtKind::Add(n) => Stmt::Add(*n),
         StmtKind::Sub(n) => Stmt::Sub(*n),
+        StmtKind::AddOffset(o, n) => Stmt::AddOffset(*o, *n),
+        StmtKind::SubOffset(o, n) => Stmt::SubOffset(*o, *n),
         StmtKind::Right(n) => Stmt::Right(u32::try_from(*n).unwrap()),
         StmtKind::Left(n) => Stmt::Left(u32::try_from(*n).unwrap()),
         StmtKind::Out => Stmt::Out,

rust2/src/codegen_interpreter.rs

@@ -6,15 +6,17 @@ const MEM_SIZE: usize = 32_000;
 
 type Memory = [Wrapping<u8>; MEM_SIZE];
 
-// TODO maybe repr(C) to prevent field reordering?
+// `repr(C)` to make sure rustc never reorders the fields weirdly
+// maybe useless, but seems to give tiny wins
+#[repr(C)]
 struct Interpreter<'c, W, R, P> {
     code: &'c Code<'c>,
+    profile_collector: P,
     ip: usize,
     ptr: usize,
+    mem: Memory,
     stdout: W,
     stdin: R,
-    mem: Memory,
-    profile_collector: P,
 }
 
 pub fn run<W, R, P>(code: &Code<'_>, stdout: W, stdin: R, profile_collector: P)
@@ -60,6 +62,16 @@ where
                 Stmt::Sub(n) => {
                     *self.elem_mut() -= n;
                 }
+                Stmt::AddOffset(o, n) => unsafe {
+                    *self
+                        .mem
+                        .get_unchecked_mut((self.ptr as isize + (o as isize)) as usize) += n;
+                },
+                Stmt::SubOffset(o, n) => unsafe {
+                    *self
+                        .mem
+                        .get_unchecked_mut((self.ptr as isize + (o as isize)) as usize) -= n;
+                },
                 Stmt::Right(n) => {
                     self.ptr += n as usize;
                     if self.ptr >= MEM_SIZE {

rust2/src/opts.rs

@@ -42,6 +42,8 @@ impl Debug for Stmt<'_> {
 pub enum StmtKind<'ir> {
     Add(u8),
     Sub(u8),
+    AddOffset(i32, u8),
+    SubOffset(i32, u8),
     Right(usize),
     Left(usize),
     Loop(Ir<'ir>),
@@ -211,9 +213,27 @@ fn pass_cancel_left_right_add_sub(ir: &mut Ir<'_>) {
     })
 }
 
-/// pass that replaces `Right(9) Add(5) Left(9)` with `AddOffset(9)`
+/// pass that replaces `Right(9) Add(5) Left(9)` with `AddOffset(9, 5)`
 #[tracing::instrument]
-fn pass_add_sub_offset(ir: &mut Ir<'_>) {}
+fn pass_add_sub_offset(ir: &mut Ir<'_>) {
+    window_pass(ir, pass_add_sub_offset, |[a, b, c]| {
+        match (a.kind(), b.kind(), c.kind()) {
+            (StmtKind::Right(r), StmtKind::Add(n), StmtKind::Left(l)) if r == l => {
+                WindowPassAction::Merge(StmtKind::AddOffset(i32::try_from(*r).unwrap(), *n))
+            }
+            (StmtKind::Left(l), StmtKind::Add(n), StmtKind::Right(r)) if r == l => {
+                WindowPassAction::Merge(StmtKind::AddOffset(-i32::try_from(*r).unwrap(), *n))
+            }
+            (StmtKind::Right(r), StmtKind::Sub(n), StmtKind::Left(l)) if r == l => {
+                WindowPassAction::Merge(StmtKind::SubOffset(i32::try_from(*r).unwrap(), *n))
+            }
+            (StmtKind::Left(l), StmtKind::Sub(n), StmtKind::Right(r)) if r == l => {
+                WindowPassAction::Merge(StmtKind::SubOffset(-i32::try_from(*r).unwrap(), *n))
+            }
+            _ => WindowPassAction::None,
+        }
+    })
+}
 
 enum WindowPassAction<'ir> {
     None,
@@ -236,13 +256,10 @@ where
             pass_recur(body);
         }
 
-        if i >= stmts.len() - (N - 1) {
+        if i + N > stmts.len() {
             break; // there aren't N elements left
         }
 
-        let a = &stmts[i];
-        let b = &stmts[i + 1];
-
         let mut elements = stmts[i..][..N].iter();
         let elements = [(); N].map(|()| elements.next().unwrap());
 
@@ -255,13 +272,16 @@ where
                 i += 1;
             }
             WindowPassAction::RemoveAll => {
-                trace!(?a, ?b, "Removing both statements");
+                trace!(?elements, "Removing all statements");
-                stmts.remove(i);
+                for _ in 0..N {
                     stmts.remove(i);
                 }
+            }
             WindowPassAction::Merge(new) => {
-                trace!(?a, ?b, ?new, "Merging statements");
+                trace!(?elements, ?new, "Merging statements");
-                stmts.remove(i + 1);
+                for _ in 1..N {
+                    stmts.remove(i);
+                }
                 stmts[i] = Stmt::new(new, merged_span);
             }
         }

rust2/test.bf

@@ -1 +1 @@
-<<>>-<<>>>>>>>>>>>+<<<<<<<<<<<>>
+<<<<->>>>