fix merge error

streamline.cm

@@ -1305,6 +1305,85 @@ var streamline = function(ir, log) {
     push: 2, setarg: 3, put: 1
   }
 
+  // Build last_ref liveness array for a function's instructions.
+  // Returns array where last_ref[slot] = last instruction index referencing that slot.
+  // Uses get_slot_refs to only visit actual slot reference positions.
+  var build_slot_liveness = function(instructions, nr_slots) {
+    var last_ref = array(nr_slots, -1)
+    var n = length(instructions)
+    var refs = null
+    var i = 0
+    var j = 0
+    var s = 0
+    var instr = null
+    var label_map = null
+    var changed = false
+    var op = null
+    var target = null
+    var tpos = 0
+
+    // Scan instructions for slot references
+    while (i < n) {
+      instr = instructions[i]
+      if (is_array(instr)) {
+        refs = get_slot_refs(instr)
+        j = 0
+        while (j < length(refs)) {
+          s = instr[refs[j]]
+          if (is_number(s) && s >= 0 && s < nr_slots) {
+            last_ref[s] = i
+          }
+          j = j + 1
+        }
+      }
+      i = i + 1
+    }
+
+    // Extend for backward jumps (loops)
+    label_map = {}
+    i = 0
+    while (i < n) {
+      instr = instructions[i]
+      if (is_text(instr) && !starts_with(instr, "_nop_")) {
+        label_map[instr] = i
+      }
+      i = i + 1
+    }
+    changed = true
+    while (changed) {
+      changed = false
+      i = 0
+      while (i < n) {
+        instr = instructions[i]
+        if (is_array(instr)) {
+          target = null
+          op = instr[0]
+          if (op == "jump") {
+            target = instr[1]
+          } else if (op == "jump_true" || op == "jump_false" || op == "jump_not_null") {
+            target = instr[2]
+          }
+          if (target != null && is_text(target)) {
+            tpos = label_map[target]
+            if (tpos != null && tpos < i) {
+              s = 0
+              while (s < nr_slots) {
+                if (last_ref[s] >= 0 && last_ref[s] >= tpos && last_ref[s] < i) {
+                  last_ref[s] = i
+                  changed = true
+                }
+                s = s + 1
+              }
+            }
+          }
+        }
+        i = i + 1
+      }
+    }
+
+    return last_ref
+  }
+
   var insert_stone_text = function(func, log) {
     var instructions = func.instructions
     var nr_slots = func.nr_slots
@@ -1320,6 +1399,7 @@ var streamline = function(ir, log) {
     var slot = 0
     var nc = 0
     var shift = 0
+    var last_ref = null
 
     if (instructions == null || length(instructions) == 0) {
       return null
@@ -1329,10 +1409,13 @@ var streamline = function(ir, log) {
       events = log.events
     }
 
+    // Build liveness info (in separate function to stay under slot limit)
+    last_ref = build_slot_liveness(instructions, nr_slots)
+
     // Walk instructions, tracking types, inserting stone_text
+    n = length(instructions)
     slot_types = array(nr_slots, T_UNKNOWN)
     result = []
-    n = length(instructions)
     i = 0
     while (i < n) {
       instr = instructions[i]
@@ -1353,9 +1436,10 @@ var streamline = function(ir, log) {
             }
           }
         } else if (op == "move") {
-          // Conservatively stone source before move if provably text
+          // Stone source before move only if source is provably text
+          // AND source slot is still live after this instruction
           slot = instr[2]
-          if (is_number(slot) && slot_is(slot_types, slot, T_TEXT)) {
+          if (is_number(slot) && slot_is(slot_types, slot, T_TEXT) && last_ref[slot] > i) {
             result[] = ["stone_text", slot]
             nc = nc + 1
             if (is_number(dpc) && i < dpc) shift = shift + 1