diff --git a/apps/qsim_amplitudes.cc b/apps/qsim_amplitudes.cc
index 01d50b96d..d37fdd6b9 100644
--- a/apps/qsim_amplitudes.cc
+++ b/apps/qsim_amplitudes.cc
@@ -30,6 +30,7 @@
 #include "../lib/run_qsim.h"
 #include "../lib/simmux.h"
 #include "../lib/util.h"
+#include "../lib/util_cpu.h"
 
 constexpr char usage[] = "usage:\n  ./qsim_amplitudes -c circuit_file "
                          "-d times_to_save_results -i input_files "
diff --git a/apps/qsim_base.cc b/apps/qsim_base.cc
index 8d365e9ad..5a7604d5b 100644
--- a/apps/qsim_base.cc
+++ b/apps/qsim_base.cc
@@ -26,7 +26,7 @@
 #include "../lib/io_file.h"
 #include "../lib/run_qsim.h"
 #include "../lib/simmux.h"
-#include "../lib/util.h"
+#include "../lib/util_cpu.h"
 
 constexpr char usage[] = "usage:\n  ./qsim_base -c circuit -d maxtime "
                          "-s seed -t threads -f max_fused_size "
diff --git a/apps/qsim_von_neumann.cc b/apps/qsim_von_neumann.cc
index c22649096..465760830 100644
--- a/apps/qsim_von_neumann.cc
+++ b/apps/qsim_von_neumann.cc
@@ -28,7 +28,7 @@
 #include "../lib/io_file.h"
 #include "../lib/run_qsim.h"
 #include "../lib/simmux.h"
-#include "../lib/util.h"
+#include "../lib/util_cpu.h"
 
 constexpr char usage[] = "usage:\n  ./qsim_von_neumann -c circuit -d maxtime "
                          "-s seed -t threads -f max_fused_size "
diff --git a/apps/qsimh_amplitudes.cc b/apps/qsimh_amplitudes.cc
index cfb5b09a5..7cb1b085e 100644
--- a/apps/qsimh_amplitudes.cc
+++ b/apps/qsimh_amplitudes.cc
@@ -30,6 +30,7 @@
 #include "../lib/run_qsimh.h"
 #include "../lib/simmux.h"
 #include "../lib/util.h"
+#include "../lib/util_cpu.h"
 
 constexpr char usage[] = "usage:\n  ./qsimh_amplitudes -c circuit_file "
                          "-d maxtime -k part1_qubits "
diff --git a/apps/qsimh_base.cc b/apps/qsimh_base.cc
index c1656a8b8..eb0c9c6ca 100644
--- a/apps/qsimh_base.cc
+++ b/apps/qsimh_base.cc
@@ -30,6 +30,7 @@
 #include "../lib/run_qsimh.h"
 #include "../lib/simmux.h"
 #include "../lib/util.h"
+#include "../lib/util_cpu.h"
 
 constexpr char usage[] = "usage:\n  ./qsimh_base -c circuit_file "
                          "-d maximum_time -k part1_qubits "
diff --git a/lib/BUILD b/lib/BUILD
index d69ae1dad..cc56dbd2b 100644
--- a/lib/BUILD
+++ b/lib/BUILD
@@ -61,6 +61,7 @@ cc_library(
         "unitary_calculator_basic.h",
         "unitary_calculator_sse.h",
         "util.h",
+        "util_cpu.h",
         "vectorspace.h",
     ],
 )
@@ -123,6 +124,7 @@ cc_library(
         "unitary_calculator_basic.h",
         "unitary_calculator_sse.h",
         "util.h",
+        "util_cpu.h",
         "util_cuda.h",
         "vectorspace.h",
         "vectorspace_cuda.h",
@@ -170,6 +172,7 @@ cc_library(
         "unitary_calculator_basic.h",
         "unitary_calculator_sse.h",
         "util.h",
+        "util_cpu.h",
         "vectorspace.h",
     ],
 )
@@ -208,6 +211,7 @@ cc_library(
         "statespace_basic.h",
         "statespace_sse.h",
         "util.h",
+        "util_cpu.h",
         "vectorspace.h",
     ],
 )
@@ -238,6 +242,11 @@ cc_library(
     hdrs = ["util.h"],
 )
 
+cc_library(
+    name = "util_cpu",
+    hdrs = ["util_cpu.h"],
+)
+
 # cuda_library
 cc_library(
     name = "util_cuda",
diff --git a/lib/util.h b/lib/util.h
index 933730c32..726a01926 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -15,10 +15,6 @@
 #ifndef UTIL_H_
 #define UTIL_H_
 
-#ifdef __SSE__
-# include <immintrin.h>
-#endif
-
 #include <algorithm>
 #include <chrono>
 #include <random>
@@ -88,23 +84,6 @@ inline std::vector<DistrRealType> GenerateRandomValues(
   return rs;
 }
 
-// This function sets flush-to-zero and denormals-are-zeros MXCSR control
-// flags. This prevents rare cases of performance slowdown potentially at
-// the cost of a tiny precision loss.
-inline void SetFlushToZeroAndDenormalsAreZeros() {
-#ifdef __SSE2__
-  _mm_setcsr(_mm_getcsr() | 0x8040);
-#endif
-}
-
-// This function clears flush-to-zero and denormals-are-zeros MXCSR control
-// flags.
-inline void ClearFlushToZeroAndDenormalsAreZeros() {
-#ifdef __SSE2__
-  _mm_setcsr(_mm_getcsr() & ~unsigned{0x8040});
-#endif
-}
-
 }  // namespace qsim
 
 #endif  // UTIL_H_
diff --git a/lib/util_cpu.h b/lib/util_cpu.h
new file mode 100644
index 000000000..8e0242524
--- /dev/null
+++ b/lib/util_cpu.h
@@ -0,0 +1,43 @@
+// Copyright 2019 Google LLC. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef UTIL_CPU_H_
+#define UTIL_CPU_H_
+
+#ifdef __SSE2__
+# include <immintrin.h>
+#endif
+
+namespace qsim {
+
+// This function sets flush-to-zero and denormals-are-zeros MXCSR control
+// flags. This prevents rare cases of performance slowdown potentially at
+// the cost of a tiny precision loss.
+inline void SetFlushToZeroAndDenormalsAreZeros() {
+#ifdef __SSE2__
+  _mm_setcsr(_mm_getcsr() | 0x8040);
+#endif
+}
+
+// This function clears flush-to-zero and denormals-are-zeros MXCSR control
+// flags.
+inline void ClearFlushToZeroAndDenormalsAreZeros() {
+#ifdef __SSE2__
+  _mm_setcsr(_mm_getcsr() & ~unsigned{0x8040});
+#endif
+}
+
+}  // namespace qsim
+
+#endif  // UTIL_CPU_H_
diff --git a/pybind_interface/avx2/pybind_main_avx2.cpp b/pybind_interface/avx2/pybind_main_avx2.cpp
index 5729d163a..1f7dc0842 100644
--- a/pybind_interface/avx2/pybind_main_avx2.cpp
+++ b/pybind_interface/avx2/pybind_main_avx2.cpp
@@ -16,6 +16,7 @@
 
 #include "../../lib/formux.h"
 #include "../../lib/simulator_avx.h"
+#include "../../lib/util_cpu.h"
 
 namespace qsim {
   template <typename For>
diff --git a/pybind_interface/avx512/pybind_main_avx512.cpp b/pybind_interface/avx512/pybind_main_avx512.cpp
index 0073a1e09..b87ececb6 100644
--- a/pybind_interface/avx512/pybind_main_avx512.cpp
+++ b/pybind_interface/avx512/pybind_main_avx512.cpp
@@ -16,6 +16,7 @@
 
 #include "../../lib/formux.h"
 #include "../../lib/simulator_avx512.h"
+#include "../../lib/util_cpu.h"
 
 namespace qsim {
   template <typename For>
diff --git a/pybind_interface/basic/pybind_main_basic.cpp b/pybind_interface/basic/pybind_main_basic.cpp
index 55cb5484b..51fdc6081 100644
--- a/pybind_interface/basic/pybind_main_basic.cpp
+++ b/pybind_interface/basic/pybind_main_basic.cpp
@@ -16,6 +16,7 @@
 
 #include "../../lib/formux.h"
 #include "../../lib/simulator_basic.h"
+#include "../../lib/util_cpu.h"
 
 namespace qsim {
   template <typename For>
diff --git a/pybind_interface/cuda/pybind_main_cuda.cpp b/pybind_interface/cuda/pybind_main_cuda.cpp
index 391cb976e..88fa3a61d 100644
--- a/pybind_interface/cuda/pybind_main_cuda.cpp
+++ b/pybind_interface/cuda/pybind_main_cuda.cpp
@@ -41,6 +41,9 @@ namespace qsim {
     StateSpace::Parameter ss_params;
     Simulator::Parameter sim_params;
   };
+
+  inline void SetFlushToZeroAndDenormalsAreZeros() {}
+  inline void ClearFlushToZeroAndDenormalsAreZeros() {}
 }
 
 #include "../pybind_main.cpp"
diff --git a/pybind_interface/custatevec/pybind_main_custatevec.cpp b/pybind_interface/custatevec/pybind_main_custatevec.cpp
index 109cedae6..1e3996335 100644
--- a/pybind_interface/custatevec/pybind_main_custatevec.cpp
+++ b/pybind_interface/custatevec/pybind_main_custatevec.cpp
@@ -53,6 +53,9 @@ struct Factory {
   custatevecHandle_t custatevec_handle;
 };
 
+inline void SetFlushToZeroAndDenormalsAreZeros() {}
+inline void ClearFlushToZeroAndDenormalsAreZeros() {}
+
 }
 
 #include "../pybind_main.cpp"
diff --git a/pybind_interface/pybind_main.cpp b/pybind_interface/pybind_main.cpp
index 428372d11..d02c0693d 100644
--- a/pybind_interface/pybind_main.cpp
+++ b/pybind_interface/pybind_main.cpp
@@ -30,7 +30,6 @@
 #include "../lib/qtrajectory.h"
 #include "../lib/run_qsim.h"
 #include "../lib/run_qsimh.h"
-#include "../lib/util.h"
 
 using namespace qsim;
 
diff --git a/pybind_interface/sse/pybind_main_sse.cpp b/pybind_interface/sse/pybind_main_sse.cpp
index 4c72a65a0..674aecad4 100644
--- a/pybind_interface/sse/pybind_main_sse.cpp
+++ b/pybind_interface/sse/pybind_main_sse.cpp
@@ -16,6 +16,7 @@
 
 #include "../../lib/formux.h"
 #include "../../lib/simulator_sse.h"
+#include "../../lib/util_cpu.h"
 
 namespace qsim {
   template <typename For>
diff --git a/tests/BUILD b/tests/BUILD
index 47f90535b..af59659ec 100644
--- a/tests/BUILD
+++ b/tests/BUILD
@@ -265,7 +265,7 @@ cc_library(
         "//lib:gate_appl",
         "//lib:gates_qsim",
         "//lib:io",
-        "//lib:util",
+        "//lib:util_cpu",
     ],
     testonly = 1,
 )
diff --git a/tests/simulator_testfixture.h b/tests/simulator_testfixture.h
index 05cad5a66..ef335565c 100644
--- a/tests/simulator_testfixture.h
+++ b/tests/simulator_testfixture.h
@@ -27,7 +27,7 @@
 #include "../lib/gate_appl.h"
 #include "../lib/gates_qsim.h"
 #include "../lib/io.h"
-#include "../lib/util.h"
+#include "../lib/util_cpu.h"
 
 namespace qsim {