diff --git a/cranelift/codegen/build.rs b/cranelift/codegen/build.rs
index dd6cfc999c..10def102be 100644
--- a/cranelift/codegen/build.rs
+++ b/cranelift/codegen/build.rs
@@ -27,15 +27,6 @@ fn main() {
     let out_dir = env::var("OUT_DIR").expect("The OUT_DIR environment variable must be set");
     let target_triple = env::var("TARGET").expect("The TARGET environment variable must be set");
 
-    let new_backend_isas = if env::var("CARGO_FEATURE_X64").is_ok() {
-        // The x64 (new backend for x86_64) is a bit particular: it only requires generating
-        // the shared meta code; the only ISA-specific code is for settings.
-        vec![meta::isa::Isa::X86]
-    } else {
-        Vec::new()
-    };
-
-    // Configure isa targets using the old backend.
     let isa_targets = meta::isa::Isa::all()
         .iter()
         .cloned()
@@ -45,7 +36,7 @@ fn main() {
         })
         .collect::<Vec<_>>();
 
-    let old_backend_isas = if new_backend_isas.is_empty() && isa_targets.is_empty() {
+    let isas = if isa_targets.is_empty() {
         // Try to match native target.
         let target_name = target_triple.split('-').next().unwrap();
         let isa = meta::isa_from_arch(&target_name).expect("error when identifying target");
@@ -65,23 +56,14 @@ fn main() {
         crate_dir.join("build.rs").to_str().unwrap()
     );
 
-    if let Err(err) = meta::generate(&old_backend_isas, &new_backend_isas, &out_dir) {
+    if let Err(err) = meta::generate(&isas, &out_dir) {
         eprintln!("Error: {}", err);
         process::exit(1);
     }
 
     if env::var("CRANELIFT_VERBOSE").is_ok() {
-        for isa in &old_backend_isas {
-            println!(
-                "cargo:warning=Includes old-backend support for {} ISA",
-                isa.to_string()
-            );
-        }
-        for isa in &new_backend_isas {
-            println!(
-                "cargo:warning=Includes new-backend support for {} ISA",
-                isa.to_string()
-            );
+        for isa in &isas {
+            println!("cargo:warning=Includes support for {} ISA", isa.to_string());
         }
         println!(
             "cargo:warning=Build step took {:?}.",
diff --git a/cranelift/codegen/meta/src/isa/x86.rs b/cranelift/codegen/meta/src/isa/x86.rs
index 2a63ef147d..eec6ac105f 100644
--- a/cranelift/codegen/meta/src/isa/x86.rs
+++ b/cranelift/codegen/meta/src/isa/x86.rs
@@ -9,7 +9,7 @@ pub(crate) fn define(shared_defs: &mut SharedDefinitions) -> TargetIsa {
     TargetIsa::new("x86", settings)
 }
 
-pub(crate) fn define_settings(shared: &SettingGroup) -> SettingGroup {
+fn define_settings(shared: &SettingGroup) -> SettingGroup {
     let mut settings = SettingGroupBuilder::new("x86");
 
     // CPUID.01H:ECX
diff --git a/cranelift/codegen/meta/src/lib.rs b/cranelift/codegen/meta/src/lib.rs
index d54e490f6c..20815ef8d2 100644
--- a/cranelift/codegen/meta/src/lib.rs
+++ b/cranelift/codegen/meta/src/lib.rs
@@ -21,11 +21,7 @@ pub fn isa_from_arch(arch: &str) -> Result<isa::Isa, String> {
 }
 
 /// Generates all the Rust source files used in Cranelift from the meta-language.
-pub fn generate(
-    old_backend_isas: &[isa::Isa],
-    new_backend_isas: &[isa::Isa],
-    out_dir: &str,
-) -> Result<(), error::Error> {
+pub fn generate(isas: &[isa::Isa], out_dir: &str) -> Result<(), error::Error> {
     // Create all the definitions:
     // - common definitions.
     let mut shared_defs = shared::define();
@@ -39,7 +35,7 @@ pub fn generate(
     gen_types::generate("types.rs", &out_dir)?;
 
     // - per ISA definitions.
-    let target_isas = isa::define(old_backend_isas, &mut shared_defs);
+    let target_isas = isa::define(isas, &mut shared_defs);
 
     // At this point, all definitions are done.
     let all_formats = shared_defs.verify_instruction_formats();
@@ -62,31 +58,5 @@ pub fn generate(
         )?;
     }
 
-    for isa in new_backend_isas {
-        match isa {
-            isa::Isa::X86 => {
-                // If the old backend ISAs contained x86, this file has already been generated.
-                if old_backend_isas.iter().any(|isa| *isa == isa::Isa::X86) {
-                    continue;
-                }
-
-                let settings = crate::isa::x86::define_settings(&shared_defs.settings);
-                gen_settings::generate(
-                    &settings,
-                    gen_settings::ParentGroup::Shared,
-                    "settings-x86.rs",
-                    &out_dir,
-                )?;
-            }
-            isa::Isa::Arm64 => {
-                // aarch64 doesn't have platform-specific settings.
-            }
-            isa::Isa::S390x => {
-                // s390x doesn't have platform-specific settings.
-            }
-            isa::Isa::Arm32 => todo!(),
-        }
-    }
-
     Ok(())
 }