diff --git a/lib/std/target/x86.zig b/lib/std/target/x86.zig
index 10d33fe6b2..866b83630f 100644
--- a/lib/std/target/x86.zig
+++ b/lib/std/target/x86.zig
@@ -2,12 +2,9 @@ const std = @import("../std.zig");
 const Cpu = std.Target.Cpu;
 
 pub const Feature = enum {
-    @"16bit_mode",
-    @"32bit_mode",
     @"3dnow",
     @"3dnowa",
     @"64bit",
-    @"64bit_mode",
     adx,
     aes,
     avx,
@@ -138,16 +135,6 @@ pub const all_features = blk: {
     const len = @typeInfo(Feature).Enum.fields.len;
     std.debug.assert(len <= Cpu.Feature.Set.needed_bit_count);
     var result: [len]Cpu.Feature = undefined;
-    result[@enumToInt(Feature.@"16bit_mode")] = .{
-        .llvm_name = "16bit-mode",
-        .description = "16-bit mode (i8086)",
-        .dependencies = featureSet(&[_]Feature{}),
-    };
-    result[@enumToInt(Feature.@"32bit_mode")] = .{
-        .llvm_name = "32bit-mode",
-        .description = "32-bit mode (80386)",
-        .dependencies = featureSet(&[_]Feature{}),
-    };
     result[@enumToInt(Feature.@"3dnow")] = .{
         .llvm_name = "3dnow",
         .description = "Enable 3DNow! instructions",
@@ -167,11 +154,6 @@ pub const all_features = blk: {
         .description = "Support 64-bit instructions",
         .dependencies = featureSet(&[_]Feature{}),
     };
-    result[@enumToInt(Feature.@"64bit_mode")] = .{
-        .llvm_name = "64bit-mode",
-        .description = "64-bit mode (x86_64)",
-        .dependencies = featureSet(&[_]Feature{}),
-    };
     result[@enumToInt(Feature.adx)] = .{
         .llvm_name = "adx",
         .description = "Support ADX instructions",