diff --git a/src/checker.rs b/src/checker.rs
index 55f4860..bf5c098 100644
--- a/src/checker.rs
+++ b/src/checker.rs
@@ -78,7 +78,7 @@
 
 use crate::{
     Allocation, AllocationKind, Block, Edit, Function, Inst, InstPosition, Operand,
-    OperandConstraint, OperandKind, OperandPos, Output, PReg, ProgPoint, RegClass, VReg,
+    OperandConstraint, OperandKind, OperandPos, Output, PReg, ProgPoint, VReg,
 };
 
 use std::collections::{HashMap, HashSet, VecDeque};
diff --git a/src/ion/data_structures.rs b/src/ion/data_structures.rs
index d1caa7f..711755e 100644
--- a/src/ion/data_structures.rs
+++ b/src/ion/data_structures.rs
@@ -185,6 +185,11 @@ pub struct LiveBundle {
     pub spill_weight_and_props: u32,
 }
 
+pub const BUNDLE_MAX_SPILL_WEIGHT: u32 = (1 << 29) - 1;
+pub const MINIMAL_FIXED_BUNDLE_SPILL_WEIGHT: u32 = BUNDLE_MAX_SPILL_WEIGHT;
+pub const MINIMAL_BUNDLE_SPILL_WEIGHT: u32 = BUNDLE_MAX_SPILL_WEIGHT - 1;
+pub const BUNDLE_MAX_NORMAL_SPILL_WEIGHT: u32 = BUNDLE_MAX_SPILL_WEIGHT - 2;
+
 impl LiveBundle {
     #[inline(always)]
     pub fn set_cached_spill_weight_and_props(
@@ -194,7 +199,7 @@ impl LiveBundle {
         fixed: bool,
         stack: bool,
     ) {
-        debug_assert!(spill_weight < ((1 << 29) - 1));
+        debug_assert!(spill_weight <= BUNDLE_MAX_SPILL_WEIGHT);
         self.spill_weight_and_props = spill_weight
             | (if minimal { 1 << 31 } else { 0 })
             | (if fixed { 1 << 30 } else { 0 })
diff --git a/src/ion/process.rs b/src/ion/process.rs
index 7ee9e1c..123ae30 100644
--- a/src/ion/process.rs
+++ b/src/ion/process.rs
@@ -13,11 +13,15 @@
 //! Main allocation loop that processes bundles.
 
 use super::{
-    spill_weight_from_constraint, CodeRange, Env, LiveBundleIndex, LiveBundleVec, LiveRangeFlag,
+    spill_weight_from_constraint, Env, LiveBundleIndex, LiveBundleVec, LiveRangeFlag,
     LiveRangeIndex, LiveRangeKey, LiveRangeList, LiveRangeListEntry, PRegIndex, RegTraversalIter,
     Requirement, SpillWeight, UseList,
 };
 use crate::{
+    ion::data_structures::{
+        CodeRange, BUNDLE_MAX_NORMAL_SPILL_WEIGHT, MINIMAL_BUNDLE_SPILL_WEIGHT,
+        MINIMAL_FIXED_BUNDLE_SPILL_WEIGHT,
+    },
     Allocation, Function, Inst, InstPosition, OperandConstraint, OperandKind, PReg, ProgPoint,
     RegAllocError,
 };
@@ -302,11 +306,11 @@ impl<'a, F: Function> Env<'a, F> {
 
         let spill_weight = if minimal {
             if fixed {
-                log::trace!("  -> fixed and minimal: spill weight 2000000");
-                2_000_000
+                log::trace!("  -> fixed and minimal");
+                MINIMAL_FIXED_BUNDLE_SPILL_WEIGHT
             } else {
-                log::trace!("  -> non-fixed and minimal: spill weight 1000000");
-                1_000_000
+                log::trace!("  -> non-fixed and minimal");
+                MINIMAL_BUNDLE_SPILL_WEIGHT
             }
         } else {
             let mut total = SpillWeight::zero();
@@ -326,7 +330,7 @@ impl<'a, F: Function> Env<'a, F> {
                     self.bundles[bundle.index()].prio,
                     final_weight
                 );
-                final_weight
+                std::cmp::min(BUNDLE_MAX_NORMAL_SPILL_WEIGHT, final_weight)
             } else {
                 0
             }