Decrease optimization level for compiling benchmarks

Calls to functions which return two values (for example sincos),
were being optimized away in new benchmark tool. Fixed by
decreasing optimization level (O3 -> O2).

src/benchmarks/CMakeLists.txt

@@ -24,28 +24,28 @@ include_directories(${sleef_BINARY_DIR}/include)   # sleef.h
 link_directories(${sleef_BINARY_DIR}/lib)          # libsleef
 
 
-set(Extra_CFLAGS -Wall -O3 -Wno-attributes)
+set(EXTRA_CFLAGS -Wall -O2 -Wno-attributes)
 set(BENCH_SRC_FILE "benchsleef.cpp" "benchmark_callers.hpp" "benchmark_templates.hpp" "gen_input.hpp" "type_defs.hpp")
 set(BENCH_PROPERTIES C_STANDARD 99 CXX_STANDARD 17)
 set(BENCH_LIBS benchmark sleef Threads::Threads) # Link Google Benchmark and sleef to the project
 
 # Add source to this project's executable.
 add_executable (benchsleef128 ${BENCH_SRC_FILE})
 set_target_properties(benchsleef128 PROPERTIES ${BENCH_PROPERTIES})
-target_compile_options(benchsleef128 PRIVATE ${Extra_CFLAGS} -march=native)
+target_compile_options(benchsleef128 PRIVATE ${EXTRA_CFLAGS} -march=native)
 target_link_libraries(benchsleef128 ${BENCH_LIBS})
 add_dependencies(benchsleef128 googlebenchmark)
 
 if(CMAKE_SYSTEM_PROCESSOR MATCHES "(x86)|(X86)|(amd64)|(AMD64)")
 	add_executable (benchsleef256 ${BENCH_SRC_FILE})
 	set_target_properties(benchsleef256 PROPERTIES ${BENCH_PROPERTIES})
-	target_compile_options(benchsleef256 PRIVATE ${Extra_CFLAGS} "-march=native" "-DARCH_VECT_LEN=256")
+	target_compile_options(benchsleef256 PRIVATE ${EXTRA_CFLAGS} "-march=native" "-DARCH_VECT_LEN=256")
 	target_link_libraries(benchsleef256 ${BENCH_LIBS})
 	add_dependencies(benchsleef256 googlebenchmark)
 
 	add_executable (benchsleef512 ${BENCH_SRC_FILE})
 	set_target_properties(benchsleef512 PROPERTIES ${BENCH_PROPERTIES})
-	target_compile_options(benchsleef512 PRIVATE ${Extra_CFLAGS} "-mavx512f" "-DARCH_VECT_LEN=512")
+	target_compile_options(benchsleef512 PRIVATE ${EXTRA_CFLAGS} "-mavx512f" "-DARCH_VECT_LEN=512")
 	target_link_libraries(benchsleef512 ${BENCH_LIBS})
 	add_dependencies(benchsleef512 googlebenchmark)
 endif()