diff --git a/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel b/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
--- a/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
@@ -193,7 +193,19 @@
         "lib/Support/BLAKE3/blake3.c",
         "lib/Support/BLAKE3/blake3_dispatch.c",
         "lib/Support/BLAKE3/blake3_portable.c",
-    ],
+    ] + select({
+        "@platforms//cpu:aarch64": [
+            "lib/Support/BLAKE3/blake3_neon.c",
+        ],
+        "@platforms//cpu:x86_64": [
+            "lib/Support/BLAKE3/blake3_sse2_x86-64_unix.S",
+            "lib/Support/BLAKE3/blake3_sse41_x86-64_unix.S",
+            "lib/Support/BLAKE3/blake3_avx2_x86-64_unix.S",
+            "lib/Support/BLAKE3/blake3_avx512_x86-64_unix.S",
+        ],
+        "//conditions:default": [
+        ]
+    }),
     hdrs = glob([
         "include/llvm/Support/**/*.h",
         "include/llvm/ADT/*.h",
@@ -213,13 +225,22 @@
         "include/llvm/Support/VCSRevision.h",
     ],
     copts = llvm_copts,
-    defines = [
-        "BLAKE3_NO_AVX2",
-        "BLAKE3_NO_AVX512",
-        "BLAKE3_NO_SSE2",
-        "BLAKE3_NO_SSE41",
-        "BLAKE3_USE_NEON=0",
-    ],
+    defines = select({
+        "@platforms//cpu:aarch64": [
+        ],
+        "//conditions:default": [
+            "BLAKE3_USE_NEON=0",
+        ]
+    }) + select({
+        "@platforms//cpu:x86_64": [
+        ],
+        "//conditions:default": [
+            "BLAKE3_NO_AVX2",
+            "BLAKE3_NO_AVX512",
+            "BLAKE3_NO_SSE2",
+            "BLAKE3_NO_SSE41",
+        ]
+    }),
     includes = ["include"],
     linkopts = select({
         "@bazel_tools//src/conditions:windows": [],