diff --git a/cranelift/codegen/meta/src/cdsl/instructions.rs b/cranelift/codegen/meta/src/cdsl/instructions.rs
index 42cf0e3af4..5a7a1931ad 100644
--- a/cranelift/codegen/meta/src/cdsl/instructions.rs
+++ b/cranelift/codegen/meta/src/cdsl/instructions.rs
@@ -1,5 +1,3 @@
-use cranelift_entity::{entity_impl, PrimaryMap};
-
 use std::fmt;
 use std::rc::Rc;
 
@@ -9,11 +7,7 @@ use crate::cdsl::operands::Operand;
 use crate::cdsl::type_inference::Constraint;
 use crate::cdsl::typevar::TypeVar;
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
-pub(crate) struct OpcodeNumber(u32);
-entity_impl!(OpcodeNumber);
-
-pub(crate) type AllInstructions = PrimaryMap<OpcodeNumber, Instruction>;
+pub(crate) type AllInstructions = Vec<Instruction>;
 
 pub(crate) struct InstructionGroupBuilder<'all_inst> {
     all_instructions: &'all_inst mut AllInstructions,
@@ -25,8 +19,7 @@ impl<'all_inst> InstructionGroupBuilder<'all_inst> {
     }
 
     pub fn push(&mut self, builder: InstructionBuilder) {
-        let opcode_number = OpcodeNumber(self.all_instructions.next_key().as_u32());
-        let inst = builder.build(opcode_number);
+        let inst = builder.build();
         self.all_instructions.push(inst);
     }
 }
@@ -42,7 +35,6 @@ pub(crate) struct InstructionContent {
     /// Instruction mnemonic, also becomes opcode name.
     pub name: String,
     pub camel_name: String,
-    pub opcode_number: OpcodeNumber,
 
     /// Documentation string.
     pub doc: String,
@@ -240,7 +232,7 @@ impl InstructionBuilder {
         self
     }
 
-    fn build(self, opcode_number: OpcodeNumber) -> Instruction {
+    fn build(self) -> Instruction {
         let operands_in = self.operands_in.unwrap_or_else(Vec::new);
         let operands_out = self.operands_out.unwrap_or_else(Vec::new);
 
@@ -275,7 +267,6 @@ impl InstructionBuilder {
         Rc::new(InstructionContent {
             name: self.name,
             camel_name,
-            opcode_number,
             doc: self.doc,
             operands_in,
             operands_out,
diff --git a/cranelift/codegen/meta/src/gen_inst.rs b/cranelift/codegen/meta/src/gen_inst.rs
index fb10dff8cb..1b3b42d73a 100644
--- a/cranelift/codegen/meta/src/gen_inst.rs
+++ b/cranelift/codegen/meta/src/gen_inst.rs
@@ -2,7 +2,6 @@
 use std::fmt;
 
 use cranelift_codegen_shared::constant_hash;
-use cranelift_entity::EntityRef;
 
 use crate::cdsl::camel_case;
 use crate::cdsl::formats::InstructionFormat;
@@ -388,7 +387,7 @@ fn gen_bool_accessor<T: Fn(&Instruction) -> bool>(
     fmtln!(fmt, "pub fn {}(self) -> bool {{", name);
     fmt.indent(|fmt| {
         let mut m = Match::new("self");
-        for inst in all_inst.values() {
+        for inst in all_inst.iter() {
             if get_attr(inst) {
                 m.arm_no_fields(format!("Self::{}", inst.camel_name), "true");
             }
@@ -424,7 +423,7 @@ fn gen_opcodes(all_inst: &AllInstructions, fmt: &mut Formatter) {
     fmt.line("pub enum Opcode {");
     fmt.indent(|fmt| {
         let mut is_first_opcode = true;
-        for inst in all_inst.values() {
+        for inst in all_inst.iter() {
             fmt.doc_comment(format!("`{}`. ({})", inst, inst.format.name));
 
             // Document polymorphism.
@@ -440,8 +439,6 @@ fn gen_opcodes(all_inst: &AllInstructions, fmt: &mut Formatter) {
 
             // Enum variant itself.
             if is_first_opcode {
-                assert!(inst.opcode_number.index() == 0);
-                // TODO the python crate requires opcode numbers to start from one.
                 fmtln!(fmt, "{} = 1,", inst.camel_name);
                 is_first_opcode = false;
             } else {
@@ -535,7 +532,7 @@ fn gen_opcodes(all_inst: &AllInstructions, fmt: &mut Formatter) {
         all_inst.len()
     );
     fmt.indent(|fmt| {
-        for inst in all_inst.values() {
+        for inst in all_inst.iter() {
             fmtln!(
                 fmt,
                 "InstructionFormat::{}, // {}",
@@ -551,7 +548,7 @@ fn gen_opcodes(all_inst: &AllInstructions, fmt: &mut Formatter) {
     fmt.line("fn opcode_name(opc: Opcode) -> &\'static str {");
     fmt.indent(|fmt| {
         let mut m = Match::new("opc");
-        for inst in all_inst.values() {
+        for inst in all_inst.iter() {
             m.arm_no_fields(
                 format!("Opcode::{}", inst.camel_name),
                 format!("\"{}\"", inst.name),
@@ -563,7 +560,7 @@ fn gen_opcodes(all_inst: &AllInstructions, fmt: &mut Formatter) {
     fmt.empty_line();
 
     // Generate an opcode hash table for looking up opcodes by name.
-    let hash_table = constant_hash::generate_table(all_inst.values(), all_inst.len(), |inst| {
+    let hash_table = constant_hash::generate_table(all_inst.iter(), all_inst.len(), |inst| {
         constant_hash::simple_hash(&inst.name)
     });
     fmtln!(
@@ -736,7 +733,7 @@ fn gen_type_constraints(all_inst: &AllInstructions, fmt: &mut Formatter) {
         all_inst.len()
     );
     fmt.indent(|fmt| {
-        for inst in all_inst.values() {
+        for inst in all_inst.iter() {
             let (ctrl_typevar, ctrl_typeset) = if let Some(poly) = &inst.polymorphic_info {
                 let index = type_sets.add(&*poly.ctrl_typevar.get_raw_typeset());
                 (Some(&poly.ctrl_typevar), index)
@@ -1130,7 +1127,7 @@ fn gen_builder(
     );
     fmt.line("pub trait InstBuilder<'f>: InstBuilderBase<'f> {");
     fmt.indent(|fmt| {
-        for inst in instructions.values() {
+        for inst in instructions.iter() {
             gen_inst_builder(inst, &*inst.format, fmt);
             fmt.empty_line();
         }
diff --git a/cranelift/codegen/meta/src/shared/mod.rs b/cranelift/codegen/meta/src/shared/mod.rs
index 549ae7cf99..5d530b27a4 100644
--- a/cranelift/codegen/meta/src/shared/mod.rs
+++ b/cranelift/codegen/meta/src/shared/mod.rs
@@ -54,7 +54,7 @@ impl Definitions {
         // of immediate fields.
         let mut format_structures: HashMap<FormatStructure, &InstructionFormat> = HashMap::new();
 
-        for inst in self.all_instructions.values() {
+        for inst in self.all_instructions.iter() {
             // Check name.
             if let Some(existing_format) = format_names.get(&inst.format.name) {
                 assert!(