diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index ae46200d3f554..3beda28ac1fd4 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -305,7 +305,6 @@ pub enum TypeKind {
     Pointer = 12,
     Vector = 13,
     Metadata = 14,
-    X86_MMX = 15,
     Token = 16,
     ScalableVector = 17,
     BFloat = 18,
@@ -330,7 +329,6 @@ impl TypeKind {
             TypeKind::Pointer => rustc_codegen_ssa::common::TypeKind::Pointer,
             TypeKind::Vector => rustc_codegen_ssa::common::TypeKind::Vector,
             TypeKind::Metadata => rustc_codegen_ssa::common::TypeKind::Metadata,
-            TypeKind::X86_MMX => rustc_codegen_ssa::common::TypeKind::X86_MMX,
             TypeKind::Token => rustc_codegen_ssa::common::TypeKind::Token,
             TypeKind::ScalableVector => rustc_codegen_ssa::common::TypeKind::ScalableVector,
             TypeKind::BFloat => rustc_codegen_ssa::common::TypeKind::BFloat,
diff --git a/compiler/rustc_codegen_ssa/src/common.rs b/compiler/rustc_codegen_ssa/src/common.rs
index 27b0f127e9262..ea2fd482e1fc2 100644
--- a/compiler/rustc_codegen_ssa/src/common.rs
+++ b/compiler/rustc_codegen_ssa/src/common.rs
@@ -91,7 +91,6 @@ pub enum TypeKind {
     Pointer,
     Vector,
     Metadata,
-    X86_MMX,
     Token,
     ScalableVector,
     BFloat,
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 14757b27a3758..4cdd8af1008c0 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -1419,8 +1419,6 @@ extern "C" LLVMTypeKind LLVMRustGetTypeKind(LLVMTypeRef Ty) {
     return LLVMPointerTypeKind;
   case Type::FixedVectorTyID:
     return LLVMVectorTypeKind;
-  case Type::X86_MMXTyID:
-    return LLVMX86_MMXTypeKind;
   case Type::TokenTyID:
     return LLVMTokenTypeKind;
   case Type::ScalableVectorTyID: