diff --git a/Cargo.toml b/Cargo.toml
index 5410cf1..ab66451 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,8 +17,11 @@ slice-group-by = "0.3.0"
 # Keep this in sync with libfuzzer_sys's crate version:
 arbitrary = { version = "^0.4.6", optional = true }
 
+# When testing regalloc2 by itself, enable debug assertions and overflow checks
 [profile.release]
 debug = true
+debug-assertions = true
+overflow-checks = true
 
 [features]
 default = []
diff --git a/fuzz/Cargo.toml b/fuzz/Cargo.toml
index 199eb9d..af37b2e 100644
--- a/fuzz/Cargo.toml
+++ b/fuzz/Cargo.toml
@@ -49,3 +49,9 @@ name = "ion_checker"
 path = "fuzz_targets/ion_checker.rs"
 test = false
 doc = false
+
+# Enable debug assertions and overflow checks when fuzzing
+[profile.release]
+debug = true
+debug-assertions = true
+overflow-checks = true
\ No newline at end of file
diff --git a/src/checker.rs b/src/checker.rs
index 9e81e27..081a64c 100644
--- a/src/checker.rs
+++ b/src/checker.rs
@@ -550,7 +550,7 @@ impl<'a, F: Function> Checker<'a, F> {
             for inst_or_edit in out.block_insts_and_edits(self.f, block) {
                 match inst_or_edit {
                     InstOrEdit::Inst(inst) => {
-                        assert!(last_inst.is_none() || inst > last_inst.unwrap());
+                        debug_assert!(last_inst.is_none() || inst > last_inst.unwrap());
                         last_inst = Some(inst);
                         self.handle_inst(block, inst, &mut safepoint_slots, out);
                     }
diff --git a/src/domtree.rs b/src/domtree.rs
index 4300e04..1bf4139 100644
--- a/src/domtree.rs
+++ b/src/domtree.rs
@@ -33,7 +33,7 @@ fn merge_sets(
             node2 = idom[node2.index()];
         }
     }
-    assert!(node1 == node2);
+    debug_assert!(node1 == node2);
     node1
 }
 
diff --git a/src/fuzzing/func.rs b/src/fuzzing/func.rs
index cbc9717..89445b4 100644
--- a/src/fuzzing/func.rs
+++ b/src/fuzzing/func.rs
@@ -79,7 +79,7 @@ impl Function for Func {
     }
 
     fn entry_block(&self) -> Block {
-        assert!(self.blocks.len() > 0);
+        debug_assert!(self.blocks.len() > 0);
         Block::new(0)
     }
 
@@ -237,7 +237,7 @@ fn choose_dominating_block(
     allow_self: bool,
     u: &mut Unstructured,
 ) -> ArbitraryResult<Block> {
-    assert!(block.is_valid());
+    debug_assert!(block.is_valid());
     let orig_block = block;
     loop {
         if (allow_self || block != orig_block) && bool::arbitrary(u)? {
@@ -445,7 +445,7 @@ impl Func {
                 if operands.len() > 1 && opts.reused_inputs && bool::arbitrary(u)? {
                     // Make the def a reused input.
                     let op = operands[0];
-                    assert_eq!(op.kind(), OperandKind::Def);
+                    debug_assert_eq!(op.kind(), OperandKind::Def);
                     let reused = u.int_in_range(1..=(operands.len() - 1))?;
                     operands[0] = Operand::new(
                         op.vreg(),
diff --git a/src/index.rs b/src/index.rs
index 21dd976..4c376fa 100644
--- a/src/index.rs
+++ b/src/index.rs
@@ -10,7 +10,7 @@ macro_rules! define_index {
             }
             #[inline(always)]
             pub fn index(self) -> usize {
-                assert!(self.is_valid());
+                debug_assert!(self.is_valid());
                 self.0 as usize
             }
             #[inline(always)]
@@ -27,12 +27,12 @@ macro_rules! define_index {
             }
             #[inline(always)]
             pub fn next(self) -> $ix {
-                assert!(self.is_valid());
+                debug_assert!(self.is_valid());
                 Self(self.0 + 1)
             }
             #[inline(always)]
             pub fn prev(self) -> $ix {
-                assert!(self.is_valid());
+                debug_assert!(self.is_valid());
                 Self(self.0 - 1)
             }
 
@@ -62,19 +62,19 @@ pub struct InstRange(Inst, Inst, bool);
 impl InstRange {
     #[inline(always)]
     pub fn forward(from: Inst, to: Inst) -> Self {
-        assert!(from.index() <= to.index());
+        debug_assert!(from.index() <= to.index());
         InstRange(from, to, true)
     }
 
     #[inline(always)]
     pub fn backward(from: Inst, to: Inst) -> Self {
-        assert!(from.index() >= to.index());
+        debug_assert!(from.index() >= to.index());
         InstRange(to, from, false)
     }
 
     #[inline(always)]
     pub fn first(self) -> Inst {
-        assert!(self.len() > 0);
+        debug_assert!(self.len() > 0);
         if self.is_forward() {
             self.0
         } else {
@@ -84,7 +84,7 @@ impl InstRange {
 
     #[inline(always)]
     pub fn last(self) -> Inst {
-        assert!(self.len() > 0);
+        debug_assert!(self.len() > 0);
         if self.is_forward() {
             self.1.prev()
         } else {
@@ -94,7 +94,7 @@ impl InstRange {
 
     #[inline(always)]
     pub fn rest(self) -> InstRange {
-        assert!(self.len() > 0);
+        debug_assert!(self.len() > 0);
         if self.is_forward() {
             InstRange::forward(self.0.next(), self.1)
         } else {
@@ -147,13 +147,13 @@ mod test {
     #[test]
     fn test_inst_range() {
         let range = InstRange::forward(Inst::new(0), Inst::new(0));
-        assert_eq!(range.len(), 0);
+        debug_assert_eq!(range.len(), 0);
 
         let range = InstRange::forward(Inst::new(0), Inst::new(5));
-        assert_eq!(range.first().index(), 0);
-        assert_eq!(range.last().index(), 4);
-        assert_eq!(range.len(), 5);
-        assert_eq!(
+        debug_assert_eq!(range.first().index(), 0);
+        debug_assert_eq!(range.last().index(), 4);
+        debug_assert_eq!(range.len(), 5);
+        debug_assert_eq!(
             range.iter().collect::<Vec<_>>(),
             vec![
                 Inst::new(0),
@@ -164,10 +164,10 @@ mod test {
             ]
         );
         let range = range.rev();
-        assert_eq!(range.first().index(), 4);
-        assert_eq!(range.last().index(), 0);
-        assert_eq!(range.len(), 5);
-        assert_eq!(
+        debug_assert_eq!(range.first().index(), 4);
+        debug_assert_eq!(range.last().index(), 0);
+        debug_assert_eq!(range.len(), 5);
+        debug_assert_eq!(
             range.iter().collect::<Vec<_>>(),
             vec![
                 Inst::new(4),
diff --git a/src/indexset.rs b/src/indexset.rs
index 35d90dd..a5c263a 100644
--- a/src/indexset.rs
+++ b/src/indexset.rs
@@ -93,7 +93,7 @@ impl AdaptiveMap {
         };
 
         if needs_expand {
-            assert!(small_mode_idx.is_none());
+            debug_assert!(small_mode_idx.is_none());
             self.expand();
         }
 
@@ -111,7 +111,7 @@ impl AdaptiveMap {
                 }
                 // Otherwise, the key must not be present; add a new
                 // entry.
-                assert!(*len < SMALL_ELEMS as u32);
+                debug_assert!(*len < SMALL_ELEMS as u32);
                 let idx = *len;
                 *len += 1;
                 keys[idx as usize] = key;
@@ -344,11 +344,11 @@ mod test {
 
         let mut checksum = 0;
         for bit in vec.iter() {
-            assert!(bit % 17 == 0);
+            debug_assert!(bit % 17 == 0);
             checksum += bit;
         }
 
-        assert_eq!(sum, checksum);
+        debug_assert_eq!(sum, checksum);
     }
 
     #[test]
@@ -362,6 +362,6 @@ mod test {
         // should still be in small mode.
         vec.set(64 * 5, false);
         vec.set(64 * 100, true);
-        assert!(vec.is_small());
+        debug_assert!(vec.is_small());
     }
 }
diff --git a/src/ion/liveranges.rs b/src/ion/liveranges.rs
index 404b438..2f7e2e6 100644
--- a/src/ion/liveranges.rs
+++ b/src/ion/liveranges.rs
@@ -199,7 +199,7 @@ impl<'a, F: Function> Env<'a, F> {
         // array, then reverse them at the end of
         // `compute_liveness()`.
 
-        assert!(
+        debug_assert!(
             self.vregs[vreg.index()].ranges.is_empty()
                 || range.to
                     <= self.ranges[self.vregs[vreg.index()]
@@ -235,7 +235,7 @@ impl<'a, F: Function> Env<'a, F> {
             // Is contiguous with previously-added range; just extend
             // its range and return it.
             let lr = self.vregs[vreg.index()].ranges.last().unwrap().index;
-            assert!(range.to == self.ranges[lr.index()].range.from);
+            debug_assert!(range.to == self.ranges[lr.index()].range.from);
             self.ranges[lr.index()].range.from = range.from;
             lr
         }
@@ -504,11 +504,11 @@ impl<'a, F: Function> Env<'a, F> {
                     if src.vreg() != dst.vreg() {
                         log::trace!(" -> move inst{}: src {} -> dst {}", inst.index(), src, dst);
 
-                        assert_eq!(src.class(), dst.class());
-                        assert_eq!(src.kind(), OperandKind::Use);
-                        assert_eq!(src.pos(), OperandPos::Early);
-                        assert_eq!(dst.kind(), OperandKind::Def);
-                        assert_eq!(dst.pos(), OperandPos::Late);
+                        debug_assert_eq!(src.class(), dst.class());
+                        debug_assert_eq!(src.kind(), OperandKind::Use);
+                        debug_assert_eq!(src.pos(), OperandPos::Early);
+                        debug_assert_eq!(dst.kind(), OperandKind::Def);
+                        debug_assert_eq!(dst.pos(), OperandPos::Late);
 
                         // If both src and dest are pinned, emit the
                         // move right here, right now.
@@ -1012,7 +1012,7 @@ impl<'a, F: Function> Env<'a, F> {
                                     );
                                     vreg_ranges[operand.vreg().vreg()] = lr;
                                 }
-                                assert!(lr.is_valid());
+                                debug_assert!(lr.is_valid());
 
                                 log::trace!("Use of {:?} at {:?} -> {:?}", operand, pos, lr,);
 
@@ -1082,7 +1082,7 @@ impl<'a, F: Function> Env<'a, F> {
                 // need to update with the final range here.
                 entry.range = self.ranges[entry.index.index()].range;
                 // Assert in-order and non-overlapping.
-                assert!(last.is_none() || last.unwrap() <= entry.range.from);
+                debug_assert!(last.is_none() || last.unwrap() <= entry.range.from);
                 last = Some(entry.range.to);
             }
         }
diff --git a/src/ion/merge.rs b/src/ion/merge.rs
index a8e1fe5..01bad4a 100644
--- a/src/ion/merge.rs
+++ b/src/ion/merge.rs
@@ -52,11 +52,11 @@ impl<'a, F: Function> Env<'a, F> {
             // Sanity check: both bundles should contain only ranges with appropriate VReg classes.
             for entry in &self.bundles[from.index()].ranges {
                 let vreg = self.ranges[entry.index.index()].vreg;
-                assert_eq!(from_rc, self.vreg_regs[vreg.index()].class());
+                debug_assert_eq!(from_rc, self.vreg_regs[vreg.index()].class());
             }
             for entry in &self.bundles[to.index()].ranges {
                 let vreg = self.ranges[entry.index.index()].vreg;
-                assert_eq!(to_rc, self.vreg_regs[vreg.index()].class());
+                debug_assert_eq!(to_rc, self.vreg_regs[vreg.index()].class());
             }
         }
 
@@ -175,7 +175,7 @@ impl<'a, F: Function> Env<'a, F> {
             for i in 0..self.bundles[to.index()].ranges.len() {
                 let entry = self.bundles[to.index()].ranges[i];
                 if last_range.is_some() {
-                    assert!(last_range.unwrap() < entry.range);
+                    debug_assert!(last_range.unwrap() < entry.range);
                 }
                 last_range = Some(entry.range);
 
@@ -321,10 +321,10 @@ impl<'a, F: Function> Env<'a, F> {
                     );
                     let src_bundle =
                         self.ranges[self.vregs[src_vreg.vreg()].ranges[0].index.index()].bundle;
-                    assert!(src_bundle.is_valid());
+                    debug_assert!(src_bundle.is_valid());
                     let dest_bundle =
                         self.ranges[self.vregs[dst_vreg.vreg()].ranges[0].index.index()].bundle;
-                    assert!(dest_bundle.is_valid());
+                    debug_assert!(dest_bundle.is_valid());
                     self.merge_bundles(/* from */ dest_bundle, /* to */ src_bundle);
                 }
             }
@@ -339,10 +339,10 @@ impl<'a, F: Function> Env<'a, F> {
                 from_vreg.index()
             );
             let to_bundle = self.ranges[self.vregs[to_vreg.index()].ranges[0].index.index()].bundle;
-            assert!(to_bundle.is_valid());
+            debug_assert!(to_bundle.is_valid());
             let from_bundle =
                 self.ranges[self.vregs[from_vreg.index()].ranges[0].index.index()].bundle;
-            assert!(from_bundle.is_valid());
+            debug_assert!(from_bundle.is_valid());
             log::trace!(
                 " -> from bundle{} to bundle{}",
                 from_bundle.index(),
@@ -384,9 +384,9 @@ impl<'a, F: Function> Env<'a, F> {
             }
 
             let src_bundle = self.ranges[src.index()].bundle;
-            assert!(src_bundle.is_valid());
+            debug_assert!(src_bundle.is_valid());
             let dest_bundle = self.ranges[dst.index()].bundle;
-            assert!(dest_bundle.is_valid());
+            debug_assert!(dest_bundle.is_valid());
             self.stats.prog_move_merge_attempt += 1;
             if self.merge_bundles(/* from */ dest_bundle, /* to */ src_bundle) {
                 self.stats.prog_move_merge_success += 1;
diff --git a/src/ion/moves.rs b/src/ion/moves.rs
index 9f913c4..c86fd1a 100644
--- a/src/ion/moves.rs
+++ b/src/ion/moves.rs
@@ -62,7 +62,7 @@ impl<'a, F: Function> Env<'a, F> {
         );
         match (from_alloc.as_reg(), to_alloc.as_reg()) {
             (Some(from), Some(to)) => {
-                assert_eq!(from.class(), to.class());
+                debug_assert_eq!(from.class(), to.class());
             }
             _ => {}
         }
@@ -148,9 +148,9 @@ impl<'a, F: Function> Env<'a, F> {
             to_vreg: VRegIndex,
             kind: HalfMoveKind,
         ) -> u64 {
-            assert!(from_block.index() < 1 << 21);
-            assert!(to_block.index() < 1 << 21);
-            assert!(to_vreg.index() < 1 << 21);
+            debug_assert!(from_block.index() < 1 << 21);
+            debug_assert!(to_block.index() < 1 << 21);
+            debug_assert!(to_vreg.index() < 1 << 21);
             ((from_block.index() as u64) << 43)
                 | ((to_block.index() as u64) << 22)
                 | ((to_vreg.index() as u64) << 1)
@@ -277,7 +277,7 @@ impl<'a, F: Function> Env<'a, F> {
                             alloc,
                             vreg.index()
                         );
-                        assert_eq!(range.from.pos(), InstPosition::Before);
+                        debug_assert_eq!(range.from.pos(), InstPosition::Before);
                         self.insert_move(
                             range.from,
                             InsertMovePrio::Regular,
@@ -816,7 +816,7 @@ impl<'a, F: Function> Env<'a, F> {
             .sort_unstable_by_key(|((_, inst), _)| inst.prev());
         let prog_move_srcs = std::mem::replace(&mut self.prog_move_srcs, vec![]);
         let prog_move_dsts = std::mem::replace(&mut self.prog_move_dsts, vec![]);
-        assert_eq!(prog_move_srcs.len(), prog_move_dsts.len());
+        debug_assert_eq!(prog_move_srcs.len(), prog_move_dsts.len());
         for (&((_, from_inst), from_alloc), &((to_vreg, to_inst), to_alloc)) in
             prog_move_srcs.iter().zip(prog_move_dsts.iter())
         {
@@ -827,9 +827,9 @@ impl<'a, F: Function> Env<'a, F> {
                 to_alloc,
                 to_vreg.index(),
             );
-            assert!(from_alloc.is_some());
-            assert!(to_alloc.is_some());
-            assert_eq!(from_inst, to_inst.prev());
+            debug_assert!(from_alloc.is_some());
+            debug_assert!(to_alloc.is_some());
+            debug_assert_eq!(from_inst, to_inst.prev());
             // N.B.: these moves happen with the *same* priority as
             // LR-to-LR moves, because they work just like them: they
             // connect a use at one progpoint (move-After) with a def
@@ -933,7 +933,7 @@ impl<'a, F: Function> Env<'a, F> {
 
             for m in moves {
                 if m.from_alloc.is_reg() && m.to_alloc.is_reg() {
-                    assert_eq!(m.from_alloc.class(), m.to_alloc.class());
+                    debug_assert_eq!(m.from_alloc.class(), m.to_alloc.class());
                 }
                 if m.from_alloc == m.to_alloc {
                     if m.to_vreg.is_some() {
@@ -1020,7 +1020,7 @@ impl<'a, F: Function> Env<'a, F> {
                                     },
                                 );
                             } else {
-                                assert!(extra_slot.is_some());
+                                debug_assert!(extra_slot.is_some());
                                 self.add_edit(
                                     pos,
                                     prio,
@@ -1093,7 +1093,7 @@ impl<'a, F: Function> Env<'a, F> {
                     m.to_vreg
                 );
                 let action = redundant_moves.process_move(m.from_alloc, m.to_alloc, m.to_vreg);
-                assert!(action.elide);
+                debug_assert!(action.elide);
                 if let Some((alloc, vreg)) = action.def_alloc {
                     log::trace!(" -> DefAlloc: alloc {} vreg {}", alloc, vreg);
                     self.add_edit(pos, prio, Edit::DefAlloc { alloc, vreg });
@@ -1122,8 +1122,8 @@ impl<'a, F: Function> Env<'a, F> {
                 .iter()
                 .map(|(_, _, _, alloc)| *alloc)
                 .collect::<Vec<_>>();
-            assert_eq!(vregs.len(), self.func.block_params(block).len());
-            assert_eq!(allocs.len(), self.func.block_params(block).len());
+            debug_assert_eq!(vregs.len(), self.func.block_params(block).len());
+            debug_assert_eq!(allocs.len(), self.func.block_params(block).len());
             for (vreg, alloc) in vregs.into_iter().zip(allocs.into_iter()) {
                 self.add_edit(
                     self.cfginfo.block_entry[block.index()],
@@ -1164,7 +1164,7 @@ impl<'a, F: Function> Env<'a, F> {
         match &edit {
             &Edit::Move { from, to, to_vreg } if from == to && to_vreg.is_none() => return,
             &Edit::Move { from, to, .. } if from.is_reg() && to.is_reg() => {
-                assert_eq!(from.as_reg().unwrap().class(), to.as_reg().unwrap().class());
+                debug_assert_eq!(from.as_reg().unwrap().class(), to.as_reg().unwrap().class());
             }
             _ => {}
         }
diff --git a/src/ion/process.rs b/src/ion/process.rs
index c45bc5b..753990b 100644
--- a/src/ion/process.rs
+++ b/src/ion/process.rs
@@ -150,7 +150,7 @@ impl<'a, F: Function> Env<'a, F> {
 
                 // Otherwise, there is a conflict.
                 let preg_key = *preg_range_iter.peek().unwrap().0;
-                assert_eq!(preg_key, key); // Assert that this range overlaps.
+                debug_assert_eq!(preg_key, key); // Assert that this range overlaps.
                 let preg_range = preg_range_iter.next().unwrap().1;
 
                 log::trace!(" -> btree contains range {:?} that overlaps", preg_range);
@@ -410,7 +410,7 @@ impl<'a, F: Function> Env<'a, F> {
 
         let spillset = self.bundles[bundle.index()].spillset;
 
-        assert!(!self.bundles[bundle.index()].ranges.is_empty());
+        debug_assert!(!self.bundles[bundle.index()].ranges.is_empty());
         // Split point *at* start is OK; this means we peel off
         // exactly one use to create a minimal bundle.
         let bundle_start = self.bundles[bundle.index()]
@@ -419,9 +419,9 @@ impl<'a, F: Function> Env<'a, F> {
             .unwrap()
             .range
             .from;
-        assert!(split_at >= bundle_start);
+        debug_assert!(split_at >= bundle_start);
         let bundle_end = self.bundles[bundle.index()].ranges.last().unwrap().range.to;
-        assert!(split_at < bundle_end);
+        debug_assert!(split_at < bundle_end);
 
         // Is the split point *at* the start? If so, peel off the
         // first use: set the split point just after it, or just
@@ -471,7 +471,7 @@ impl<'a, F: Function> Env<'a, F> {
             }
         }
 
-        assert!(split_at > bundle_start && split_at < bundle_end);
+        debug_assert!(split_at > bundle_start && split_at < bundle_end);
 
         // We need to find which LRs fall on each side of the split,
         // which LR we need to split down the middle, then update the
@@ -516,7 +516,7 @@ impl<'a, F: Function> Env<'a, F> {
         // down the middle, replace it with a new LR and chop off the
         // end of the same LR in the original list.
         if split_at > new_lr_list[0].range.from {
-            assert_eq!(last_lr_in_old_bundle_idx, first_lr_in_new_bundle_idx);
+            debug_assert_eq!(last_lr_in_old_bundle_idx, first_lr_in_new_bundle_idx);
             let orig_lr = new_lr_list[0].index;
             let new_lr = self.create_liverange(CodeRange {
                 from: split_at,
@@ -749,7 +749,7 @@ impl<'a, F: Function> Env<'a, F> {
                 // We have to split right away. We'll find a point to
                 // split that would allow at least the first half of the
                 // split to be conflict-free.
-                assert!(
+                debug_assert!(
                     !self.minimal_bundle(bundle),
                     "Minimal bundle with conflict!"
                 );
@@ -932,7 +932,7 @@ impl<'a, F: Function> Env<'a, F> {
             );
 
             // If we reach here, we *must* have an option either to split or evict.
-            assert!(
+            debug_assert!(
                 lowest_cost_split_conflict_cost.is_some()
                     || lowest_cost_evict_conflict_cost.is_some()
             );
diff --git a/src/lib.rs b/src/lib.rs
index 9639b0f..f1a5d70 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -234,7 +234,7 @@ impl SpillSlot {
     /// Create a new SpillSlot of a given class.
     #[inline(always)]
     pub fn new(slot: usize, class: RegClass) -> Self {
-        assert!(slot < (1 << 24));
+        debug_assert!(slot < (1 << 24));
         SpillSlot {
             bits: (slot as u32) | (class as u8 as u32) << 24,
         }
@@ -412,11 +412,11 @@ impl Operand {
             OperandConstraint::Reg => 1,
             OperandConstraint::Stack => 2,
             OperandConstraint::FixedReg(preg) => {
-                assert_eq!(preg.class(), vreg.class());
+                debug_assert_eq!(preg.class(), vreg.class());
                 0b1000000 | preg.hw_enc() as u32
             }
             OperandConstraint::Reuse(which) => {
-                assert!(which <= 31);
+                debug_assert!(which <= 31);
                 0b0100000 | which as u32
             }
         };
@@ -696,7 +696,7 @@ impl Allocation {
     /// Construct a new Allocation.
     #[inline(always)]
     pub(crate) fn new(kind: AllocationKind, index: usize) -> Self {
-        assert!(index < (1 << 28));
+        debug_assert!(index < (1 << 28));
         Self {
             bits: ((kind as u8 as u32) << 29) | (index as u32),
         }
diff --git a/src/moves.rs b/src/moves.rs
index 0bb388e..e961654 100644
--- a/src/moves.rs
+++ b/src/moves.rs
@@ -183,7 +183,7 @@ impl<T: Clone + Copy + Default> ParallelMoves<T> {
                             scratch_src = Some(src);
                             src = self.scratch;
                         } else {
-                            assert_eq!(last_dst.unwrap(), src);
+                            debug_assert_eq!(last_dst.unwrap(), src);
                         }
                         ret.push((src, dst, dst_t));