Revert "Fix bit packing of bundle params (#192)"

This reverts commit d251c8e.

Author: cfallin

src/ion/data_structures.rs

@@ -241,6 +241,11 @@ impl LiveBundle {
         self.spill_weight_and_props & (1 << 29) != 0
     }
 
+    #[inline(always)]
+    pub fn cached_stack(&self) -> bool {
+        self.spill_weight_and_props & (1 << 28) != 0
+    }
+
     #[inline(always)]
     pub fn set_cached_fixed(&mut self) {
         self.spill_weight_and_props |= 1 << 30;
@@ -251,9 +256,14 @@ impl LiveBundle {
         self.spill_weight_and_props |= 1 << 29;
     }
 
+    #[inline(always)]
+    pub fn set_cached_stack(&mut self) {
+        self.spill_weight_and_props |= 1 << 28;
+    }
+
     #[inline(always)]
     pub fn cached_spill_weight(&self) -> u32 {
-        self.spill_weight_and_props & BUNDLE_MAX_SPILL_WEIGHT
+        self.spill_weight_and_props & ((1 << 28) - 1)
     }
 }
 

src/ion/merge.rs

@@ -112,7 +112,11 @@ impl<'a, F: Function> Env<'a, F> {
         }
 
         // Check for a requirements conflict.
-        if self.bundles[from].cached_fixed() || self.bundles[to].cached_fixed() {
+        if self.bundles[from].cached_stack()
+            || self.bundles[from].cached_fixed()
+            || self.bundles[to].cached_stack()
+            || self.bundles[to].cached_fixed()
+        {
             if self.merge_bundle_requirements(from, to).is_err() {
                 trace!(" -> conflicting requirements; aborting merge");
                 return false;
@@ -154,6 +158,9 @@ impl<'a, F: Function> Env<'a, F> {
             }
             self.bundles[to].ranges = list;
 
+            if self.bundles[from].cached_stack() {
+                self.bundles[to].set_cached_stack();
+            }
             if self.bundles[from].cached_fixed() {
                 self.bundles[to].set_cached_fixed();
             }
@@ -236,6 +243,9 @@ impl<'a, F: Function> Env<'a, F> {
             *to_range = to_range.join(from_range);
         }
 
+        if self.bundles[from].cached_stack() {
+            self.bundles[to].set_cached_stack();
+        }
         if self.bundles[from].cached_fixed() {
             self.bundles[to].set_cached_fixed();
         }