Optimize pop_i32_into, check more fib values

src/backend.rs

@@ -397,10 +397,33 @@ fn pop_i32(ctx: &mut Context) -> Value {
 }
 
 fn pop_i32_into(ctx: &mut Context, dst: ValueLocation) {
-    let val = pop_i32(ctx);
-    let val_loc = val.location(&ctx.locals);
-    copy_value(ctx, val_loc, dst);
-    free_val(ctx, val);
+    let to_move = match ctx.block_state.stack.pop().expect("Stack is empty") {
+        StackValue::Local(loc) => Value::Local(loc),
+        StackValue::Immediate(i) => Value::Immediate(i),
+        StackValue::Temp(reg) => Value::Temp(reg),
+        StackValue::Pop => {
+            ctx.block_state.depth.free(1);
+            match dst {
+                ValueLocation::Reg(r) => dynasm!(ctx.asm
+                    ; pop Rq(r)
+                ),
+                ValueLocation::Stack(offset) => {
+                    let offset = adjusted_offset(ctx, offset);
+                    dynasm!(ctx.asm
+                        ; pop QWORD [rsp + offset]
+                    )
+                }
+                ValueLocation::Immediate(_) => panic!("Tried to write to literal!"),
+            }
+
+            // DO NOT DO A `copy_val`
+            return;
+        }
+    };
+
+    let src = to_move.location(&ctx.locals);
+    copy_value(ctx, src, dst);
+    free_val(ctx, to_move);
 }
 
 fn free_val(ctx: &mut Context, val: Value) {

src/tests.rs

@@ -317,17 +317,23 @@ const FIBONACCI: &str = r#"
 
 #[test]
 fn fib() {
-    // fac(x) = y <=> (x, y)
-    const FIB_SEQ: &[u32] = &[1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
+    fn fib(n: u32) -> u32 {
+        let (mut a, mut b) = (1, 1);
+
+        for _ in 0..n {
+            let old_a = a;
+            a = b;
+            b += old_a;
+        }
+
+        a
+    }
 
     let translated = translate_wat(FIBONACCI);
 
-    for x in 0..10 {
+    for x in 0..30 {
         unsafe {
-            assert_eq!(
-                translated.execute_func::<_, u32>(0, (x,)),
-                FIB_SEQ[x as usize]
-            );
+            assert_eq!(translated.execute_func::<_, u32>(0, (x,)), fib(x));
         }
     }
 }