Add -mbmi2 flag when -mavx2 is used in Makefiles (#992)

It looks like it's possible to use the `-mbmi2` flag when `-mavx2` is
used, based on documentation and on testing locally. This was done in
some Makefiles but not consistently. This PR adds the flag to Makefiles
where it was missing, plus also in one BUILD file.

Author: mhucka

pybind_interface/avx2/CMakeLists.txt

@@ -20,8 +20,15 @@ if(WIN32)
     # Add /O2 to any configuration that is NOT Debug.
     # This prevents a conflict with /RTC1 in DEBUG builds.
     add_compile_options($<$<NOT:$<CONFIG:Debug>>:/O2>)
-else()
+elseif(LINUX)
     add_compile_options(-mavx2 -mfma -O3 -flto=auto)
+    execute_process(
+        COMMAND bash --noprofile -c "grep -qs bmi2 /proc/cpuinfo"
+        RESULT_VARIABLE _EXIT_CODE
+    )
+    if(_EXIT_CODE EQUAL 0)
+        add_compile_options("-mbmi2")
+    endif()
 endif()
 
 if(APPLE)

tests/Makefile

@@ -13,33 +13,34 @@
 # limitations under the License.
 
 # Determine the hardware features available in this CPU.
-HAVE_SSE := $(shell grep -qs sse /proc/cpuinfo && echo "true")
 HAVE_AVX2 := $(shell grep -qs avx2 /proc/cpuinfo && echo "true")
 HAVE_AVX512 := $(shell grep -qs avx512f /proc/cpuinfo && echo "true")
+HAVE_BMI2 := $(shell grep -qs bmi2 /proc/cpuinfo && echo "true")
+HAVE_SSE := $(shell grep -qs sse /proc/cpuinfo && echo "true")
 
 # Default targets. Always built.
 BASIC_FILES := $(shell ls *.cc | egrep -v '_avx|_sse')
 
 # Additional flags and targets for non-CUDA cases.
-SSE_FILES =
-AVX2_FILES =
-AVX512_FILES =
-ifneq (,$(HAVE_SSE))
-    SSE_FLAGS ?= -msse4
-    SSE_FILES := $(wildcard *_sse_test.cc)
-endif
 ifneq (,$(HAVE_AVX2))
     AVX2_FLAGS ?= -mavx2 -mfma
     AVX2_FILES := $(wildcard *_avx_test.cc)
 endif
 ifneq (,$(HAVE_AVX512))
-    AVX512_FLAGS ?= -mavx512f -mbmi2
+    AVX512_FLAGS ?= -mavx512f
     AVX512_FILES := $(wildcard *_avx512_test.cc)
 endif
+ifneq (,$(HAVE_BMI2))
+    BMI2_FLAGS ?= -mbmi2
+endif
+ifneq (,$(HAVE_SSE))
+    SSE_FLAGS ?= -msse4
+    SSE_FILES := $(wildcard *_sse_test.cc)
+endif
 
 CXX_FILES := $(BASIC_FILES) $(SSE_FILES) $(AVX2_FILES) $(AVX512_FILES)
 CXX_TARGETS := $(CXX_FILES:%.cc=%.x)
-CXXFLAGS := $(CXXFLAGS) $(SSE_FLAGS) $(AVX2_FLAGS) $(AVX512_FLAGS)
+CXXFLAGS := $(CXXFLAGS) $(SSE_FLAGS) $(AVX2_FLAGS) $(AVX512_FLAGS) $(BMI2_FLAGS)
 
 CUDA_FILES := $(wildcard *cuda_test.cu)
 CUDA_TARGETS := $(CUDA_FILES:%cuda_test.cu=%cuda_test.x)
@@ -125,8 +126,17 @@ clean:
 	-rm -f ./*.x ./*.a ./*.so ./*.mod
 	rm -rf $(GTEST_DIR)/build
 
-LOCAL_VARS = HAVE_SSE HAVE_AVX2 HAVE_AVX512 SSE_FLAGS AVX2_FLAGS $\
-	AVX512_FLAGS CXXFLAGS CXX_TARGETS TEST_FLAGS
+LOCAL_VARS = BASIC_FILES CXX_FILES CXX_TARGETS CXXFLAGS $\
+    CUDA_FILES CUDA_TARGETS $\
+    CUSTATEVEC_FILES CUSTATEVEC_FLAGS $\
+    CUSTATEVECEX_FILES CUSTATEVECEX_FLAGS $\
+	HAVE_AVX2 AVX2_FILES AVX2_FLAGS $\
+	HAVE_AVX512 AVX512_FILES AVX512_FLAGS $\
+    HAVE_BMI2 BMI2_FLAGS $\
+    HAVE_SSE SSE_FILES SSE_FLAGS $\
+	HIP_FILES HIP_TARGETS $\
+    GMOCK_DIR GTEST_DIR $\
+    TESTFLAGS
 
 .PHONY: print-vars
 print-vars: ; @$(foreach n,$(sort $(LOCAL_VARS)),echo $n=$($n);)