diff --git a/Cargo.lock b/Cargo.lock
index 725e2ad50..ed6d2ebd6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1101,7 +1101,7 @@ checksum = "8dd5a6d5999d9907cda8ed67bbd137d3af8085216c2ac62de5be860bd41f304a"
 [[package]]
 name = "lock_api"
 version = "0.4.2"
-source = "git+https://github.com/coolreader18/parking_lot?branch=remutex-is_owned#391cf555e94c05450cea2e88b42c95c6631ab163"
+source = "git+https://github.com/Amanieu/parking_lot#2b3032f95d4aa5b1ccdf41b937c60603f569763c"
 dependencies = [
  "scopeguard",
 ]
diff --git a/bytecode/src/lib.rs b/bytecode/src/lib.rs
index 49b8b7d20..73e2e173d 100644
--- a/bytecode/src/lib.rs
+++ b/bytecode/src/lib.rs
@@ -11,7 +11,7 @@ use num_bigint::BigInt;
 use num_complex::Complex64;
 use serde::{Deserialize, Serialize};
 use std::collections::BTreeSet;
-use std::fmt;
+use std::{fmt, hash};
 
 /// Sourcecode location.
 #[derive(Clone, Copy, Debug, Default, PartialEq, Serialize, Deserialize)]
@@ -103,7 +103,7 @@ impl ConstantBag for BasicBag {
 
 /// Primary container of a single code object. Each python function has
 /// a codeobject. Also a module has a codeobject.
-#[derive(Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Clone, Serialize, Deserialize)]
 pub struct CodeObject<C: Constant = ConstantData> {
     pub instructions: Box<[Instruction]>,
     pub locations: Box<[Location]>,
@@ -400,8 +400,9 @@ bitflags! {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum ConstantData {
+    Tuple { elements: Vec<ConstantData> },
     Integer { value: BigInt },
     Float { value: f64 },
     Complex { value: Complex64 },
@@ -409,11 +410,56 @@ pub enum ConstantData {
     Str { value: String },
     Bytes { value: Vec<u8> },
     Code { code: Box<CodeObject> },
-    Tuple { elements: Vec<ConstantData> },
     None,
     Ellipsis,
 }
 
+impl PartialEq for ConstantData {
+    fn eq(&self, other: &Self) -> bool {
+        use ConstantData::*;
+        match (self, other) {
+            (Integer { value: a }, Integer { value: b }) => a == b,
+            // we want to compare floats *by actual value* - if we have the *exact same* float
+            // already in a constant cache, we want to use that
+            (Float { value: a }, Float { value: b }) => a.to_bits() == b.to_bits(),
+            (Complex { value: a }, Complex { value: b }) => {
+                a.re.to_bits() == b.re.to_bits() && a.im.to_bits() == b.im.to_bits()
+            }
+            (Boolean { value: a }, Boolean { value: b }) => a == b,
+            (Str { value: a }, Str { value: b }) => a == b,
+            (Bytes { value: a }, Bytes { value: b }) => a == b,
+            (Code { code: a }, Code { code: b }) => std::ptr::eq(a.as_ref(), b.as_ref()),
+            (Tuple { elements: a }, Tuple { elements: b }) => a == b,
+            (None, None) => true,
+            (Ellipsis, Ellipsis) => true,
+            _ => false,
+        }
+    }
+}
+impl Eq for ConstantData {}
+
+impl hash::Hash for ConstantData {
+    fn hash<H: hash::Hasher>(&self, state: &mut H) {
+        use ConstantData::*;
+        std::mem::discriminant(self).hash(state);
+        match self {
+            Integer { value } => value.hash(state),
+            Float { value } => value.to_bits().hash(state),
+            Complex { value } => {
+                value.re.to_bits().hash(state);
+                value.im.to_bits().hash(state);
+            }
+            Boolean { value } => value.hash(state),
+            Str { value } => value.hash(state),
+            Bytes { value } => value.hash(state),
+            Code { code } => std::ptr::hash(code.as_ref(), state),
+            Tuple { elements } => elements.hash(state),
+            None => {}
+            Ellipsis => {}
+        }
+    }
+}
+
 pub enum BorrowedConstant<'a, C: Constant> {
     Integer { value: &'a BigInt },
     Float { value: f64 },
diff --git a/compiler/src/compile.rs b/compiler/src/compile.rs
index e25bd7c01..3dfd7731a 100644
--- a/compiler/src/compile.rs
+++ b/compiler/src/compile.rs
@@ -157,7 +157,7 @@ impl Compiler {
 
             blocks: vec![ir::Block::default()],
             current_block: bytecode::Label(0),
-            constants: Vec::new(),
+            constants: IndexSet::default(),
             name_cache: IndexSet::default(),
             varname_cache: IndexSet::default(),
             cellvar_cache: IndexSet::default(),
@@ -235,7 +235,7 @@ impl Compiler {
 
             blocks: vec![ir::Block::default()],
             current_block: bytecode::Label(0),
-            constants: Vec::new(),
+            constants: IndexSet::default(),
             name_cache: IndexSet::default(),
             varname_cache: IndexSet::default(),
             cellvar_cache,
@@ -2377,8 +2377,7 @@ impl Compiler {
 
     fn emit_constant(&mut self, constant: ConstantData) {
         let info = self.current_codeinfo();
-        let idx = info.constants.len() as u32;
-        info.constants.push(constant);
+        let idx = info.constants.insert_full(constant).0 as u32;
         self.emit(Instruction::LoadConst { idx })
     }
 
diff --git a/compiler/src/ir.rs b/compiler/src/ir.rs
index 89cecc850..d2926bf6e 100644
--- a/compiler/src/ir.rs
+++ b/compiler/src/ir.rs
@@ -37,7 +37,7 @@ pub struct CodeInfo {
 
     pub blocks: Vec<Block>,
     pub current_block: BlockIdx,
-    pub constants: Vec<ConstantData>,
+    pub constants: IndexSet<ConstantData>,
     pub name_cache: IndexSet<String>,
     pub varname_cache: IndexSet<String>,
     pub cellvar_cache: IndexSet<String>,
@@ -104,7 +104,7 @@ impl CodeInfo {
             max_stacksize,
             instructions: instructions.into_boxed_slice(),
             locations: locations.into_boxed_slice(),
-            constants: constants.into(),
+            constants: constants.into_iter().collect(),
             names: name_cache.into_iter().collect(),
             varnames: varname_cache.into_iter().collect(),
             cellvars: cellvar_cache.into_iter().collect(),