diff -Naurp a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt	2020-03-01 20:39:57.000000000 +0000
+++ b/CMakeLists.txt	2020-03-01 23:39:56.619280694 +0000
@@ -134,16 +134,7 @@ else()
 endif()
 
 # CPU flags
-if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "x86_64|AMD64" AND NOT MSVC)
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} \
-  -mavx2 \
-  -mfma \
-  -Xclang -mprefer-vector-width=128 \
-  -Xclang -target-cpu -Xclang haswell \
-  -Xclang -target-feature -Xclang +avx2")
-elseif(${CMAKE_SYSTEM_PROCESSOR} MATCHES "x86_64|AMD64" AND MSVC)
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /arch:AVX2")
-elseif(${CMAKE_SYSTEM_PROCESSOR} MATCHES "aarch64")
+if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "aarch64")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} \
   -Xclang -mprefer-vector-width=128 \
   -Xclang -target-cpu -Xclang cortex-a72")
diff -Naurp a/third_party/highway/hwy/targets.h b/third_party/highway/hwy/targets.h
--- a/third_party/highway/hwy/targets.h	2020-03-01 20:30:01.000000000 +0000
+++ b/third_party/highway/hwy/targets.h	2020-03-02 01:26:53.807156122 +0000
@@ -25,10 +25,10 @@
 #define HWY_WASM 32
 
 // Uncomment to avoid using/requiring AVX2 when running on Intel/AMD.
-// #define HWY_DISABLE_AVX2
+#define HWY_DISABLE_AVX2
 
 // Uncomment to avoid additional (optional) code generation for AVX-512 when
 // building for Intel/AMD.
-// #define HWY_DISABLE_AVX512
+#define HWY_DISABLE_AVX512
 
 #endif  // HWY_TARGETS_H_