cur changes

src/ion/fast_alloc.rs

@@ -909,6 +909,18 @@ fn handle_out_block_params<'a, F: Function>(
         let out_params = state.func.branch_blockparams(block, last_inst, 0);
         debug_assert_eq!(in_params.len(), out_params.len());
 
+        // TODO: need to break cycles
+        // e.g.
+        // Move v144 from slot 5 to slot 2 for v135
+        // Move v145 from slot 6 to slot 3 for v136
+        // Move v146 from slot 3 to slot 4 for v137
+        // or
+        // 6->3
+        // 3->5
+        // 5->6
+        // or
+        // 3->6
+        // 6->3
         for i in 0..in_params.len() {
             let in_vreg = in_params[i];
             let out_vreg = out_params[i];
@@ -999,6 +1011,11 @@ fn handle_out_block_params<'a, F: Function>(
                     vregs_passed.push(out_vreg);
 
                     if !state.liveouts[block.index()].get(out_vreg.vreg()) {
+                        trace!(
+                            "{} died at the edge, reuse stack slot for {}",
+                            out_vreg,
+                            in_vreg
+                        );
                         // we can reuse the stack slot since the variable dies
                         state.vregs[in_vreg.vreg()].slot_idx =
                             Some(state.vregs[out_vreg.vreg()].slot_idx.unwrap());
@@ -1207,6 +1224,11 @@ fn calc_live_bitmaps<'a, F: Function>(
 
         for &pred in state.func.block_preds(block) {
             if state.liveouts[pred.index()].union_with(&live) {
+                trace!(
+                    "liveouts of block{} changed to: {:?}",
+                    pred.index(),
+                    state.liveouts[pred.index()]
+                );
                 if !workqueue_set.is_set(pred.index()) {
                     workqueue_set.set(pred.index());
                     workqueue.push_back(pred);