C++ 在CMakeLists.txt文件中启用优化标志

这是我第一次在这里问问题

预备役 我已经编写了一些代码来比较过滤器（如Bloom filter等）。 代码是可用的

在执行各种基准测试时，我注意到在标志之间切换

SET(CMAKE_CXX_FLAGS "-O0 -mavx2 -mbmi2")

或

大幅更改基准测试（某些测试快1000倍）

我试图确定哪个（或多个）特定标志导致了这种速度加快

问题陈述 我尝试手动添加标志，例如编写：

SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -finline-functions -funswitch-loops -fpredictive-commoning -fgcse-after-reload -ftree-vectorize -fipa-cp-clone")

虽然我添加了所有提到的标志，但它并没有导致这样的加速

我是否正确启用了优化标志

感谢阅读，欢迎任何帮助

完整的CMakeLists.txt文件：

cmake_minimum_required(VERSION 3.14)
project(Filters)

set(CMAKE_CXX_STANDARD 14)
#SET(CMAKE_CXX_FLAGS "-O0 -mavx2 -mbmi2")
#SET(CMAKE_CXX_FLAGS "-O1 -mavx2 -mbmi2")
#SET(CMAKE_CXX_FLAGS "-O2 -mavx2 -mbmi2")
#SET(CMAKE_CXX_FLAGS "-O3 -mavx2 -mbmi2")
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mavx2 -mbmi2  -fauto-inc-dec -fcompare-elim -fcprop-registers -fdce -fdefer-pop -fdelayed-branch -fdse -fguess-branch-probability -fif-conversion2 -fif-conversion -fipa-pure-const -fipa-profile -fipa-reference -fmerge-constants -fsplit-wide-types -ftree-bit-ccp -ftree-builtin-call-dce -ftree-ccp -ftree-ch -ftree-copyrename -ftree-dce -ftree-dominator-opts -ftree-dse -ftree-forwprop -ftree-fre -ftree-phiprop -ftree-sra -ftree-pta -ftree-ter -funit-at-a-time -DNDEBUG -fthread-jumps -falign-functions  -falign-jumps -falign-loops  -falign-labels -fcaller-saves -fcrossjumping -fcse-follow-jumps  -fcse-skip-blocks -fdelete-null-pointer-checks -fdevirtualize -fexpensive-optimizations -fgcse  -fgcse-lm -finline-small-functions -findirect-inlining -fipa-sra -foptimize-sibling-calls -fpartial-inlining -fpeephole2 -fregmove -freorder-blocks  -freorder-functions -frerun-cse-after-loop -fsched-interblock  -fsched-spec -fschedule-insns  -fschedule-insns2 -fstrict-aliasing -fstrict-overflow -ftree-switch-conversion -ftree-pre -ftree-vrp")

#include_directories(.)
include_directories(Bloom_Filter)
include_directories(PD_Filter)
include_directories(Tests)
include_directories(morton)
include_directories(xorfilter)
include_directories(cuckoofilter)

find_package(OpenSSL REQUIRED)

add_executable(
        Filters
        hashutil.h
        Tests/wrappers.hpp
        Tests/tests.hpp Tests/tests.cpp
        Tests/new_tests.hpp Tests/new_tests.cpp
        Tests/printutil.cpp Tests/printutil.hpp
        Bloom_Filter/counting_bloom.h
        Bloom_Filter/simd-block.h
        Bloom_Filter/simd-block-fixed-fpp.h

        PD_Filter/PD.cpp
        PD_Filter/hashutil.hpp PD_Filter/hashutil.cpp
        PD_Filter/hash_table.hpp PD_Filter/hash_table.cpp
        PD_Filter/dict.hpp
        PD_Filter/macros.h

        #        main.cpp
        #        morton/hash_util.h
        #        morton/block.h
        #        morton/bf.h
        #        morton/block.h
        #        morton/compressed_cuckoo_config.h
        #        morton/compressed_cuckoo_filter.h
        #        morton/fixed_point.h
        #        morton/morton_filter.h
        #        morton/morton_sample_configs.h
        #        morton/morton_util.h
        #        morton/test_util.h
        #        morton/util.h
        #        morton/vector_types.h
        Tests/high_load.cpp Tests/high_load.hpp)

target_link_libraries(Filters OpenSSL::SSL)

编辑 现在使用

添加编译选项

：

cmake_minimum_required(VERSION 3.14)
project(Filters)

set(CMAKE_CXX_STANDARD 14)
#SET(CMAKE_CXX_FLAGS "-O0 -mavx2 -mbmi2")
#SET(CMAKE_CXX_FLAGS "-O1 -mavx2 -mbmi2")
#SET(CMAKE_CXX_FLAGS "-O2 -mavx2 -mbmi2")
#SET(CMAKE_CXX_FLAGS "-O3 -mavx2 -mbmi2")

#include_directories(.)
include_directories(Bloom_Filter)
include_directories(PD_Filter)
include_directories(Tests)
include_directories(morton)
include_directories(xorfilter)
include_directories(cuckoofilter)

find_package(OpenSSL REQUIRED)
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mavx2 -mbmi2 -DNDEBUG")

add_compile_options(-fauto-inc-dec -fbranch-count-reg -fcombine-stack-adjustments -fcompare-elim -fcprop-registers -fdce -fdefer-pop -fdelayed-branch -fdse -fforward-propagate -fguess-branch-probability -fif-conversion -fif-conversion2 -finline-functions-called-once -fipa-profile -fipa-pure-const -fipa-reference -fmerge-constants -fmove-loop-invariants -fomit-frame-pointer -freorder-blocks -fshrink-wrap -fshrink-wrap-separate -fsplit-wide-types -fssa-backprop -fssa-phiopt -ftree-bit-ccp -ftree-ccp -ftree-ch -ftree-coalesce-vars -ftree-copy-prop -ftree-dce -ftree-dominator-opts -ftree-dse -ftree-forwprop -ftree-fre -ftree-phiprop -ftree-pta -ftree-scev-cprop -ftree-sink -ftree-slsr -ftree-sra -ftree-ter -funit-at-a-time -falign-functions  -falign-jumps -falign-labels  -falign-loops -fcaller-saves -fcode-hoisting -fcrossjumping -fcse-follow-jumps  -fcse-skip-blocks -fdelete-null-pointer-checks -fdevirtualize  -fdevirtualize-speculatively -fexpensive-optimizations -fsplit-loops -fgcse  -fgcse-lm -fhoist-adjacent-loads -finline-functions -finline-small-functions -findirect-inlining -fipa-bit-cp  -fipa-cp  -fipa-icf -fipa-ra  -fipa-sra  -fipa-vrp -fisolate-erroneous-paths-dereference -flra-remat -foptimize-sibling-calls -foptimize-strlen -fpartial-inlining -fpeephole2 -freorder-blocks-algorithm=stc -freorder-blocks-and-partition  -freorder-functions -frerun-cse-after-loop -fschedule-insns  -fschedule-insns2 -fsched-interblock  -fsched-spec -fstore-merging -fstrict-aliasing -fthread-jumps -ftree-builtin-call-dce -ftree-pre -ftree-switch-conversion  -ftree-tail-merge -ftree-vrp -fgcse-after-reload -fipa-cp-clone -floop-interchange -floop-unroll-and-jam -fpeel-loops -fpredictive-commoning -fsplit-loops -fsplit-paths -ftree-loop-distribution -ftree-loop-vectorize -ftree-partial-pre -ftree-slp-vectorize -funswitch-loops -fvect-cost-model -fvect-cost-model=dynamic)
add_executable(
        Filters
        hashutil.h
        Tests/wrappers.hpp
        Tests/tests.hpp Tests/tests.cpp
        Tests/new_tests.hpp Tests/new_tests.cpp
        Tests/printutil.cpp Tests/printutil.hpp
        Bloom_Filter/counting_bloom.h
        Bloom_Filter/simd-block.h
        Bloom_Filter/simd-block-fixed-fpp.h

        PD_Filter/PD.cpp
        PD_Filter/hashutil.hpp PD_Filter/hashutil.cpp
        PD_Filter/hash_table.hpp PD_Filter/hash_table.cpp
        PD_Filter/dict.hpp
        PD_Filter/macros.h

        #        main.cpp
        #        morton/hash_util.h
        #        morton/block.h
        #        morton/bf.h
        #        morton/block.h
        #        morton/compressed_cuckoo_config.h
        #        morton/compressed_cuckoo_filter.h
        #        morton/fixed_point.h
        #        morton/morton_filter.h
        #        morton/morton_sample_configs.h
        #        morton/morton_util.h
        #        morton/test_util.h
        #        morton/util.h
        #        morton/vector_types.h
        Tests/high_load.cpp Tests/high_load.hpp)



target_link_libraries(Filters OpenSSL::SSL)

---

欢迎来到堆栈溢出！注意，链接的GCC页面描述了每个优化级别启用更多标志（

-O1

添加一些标志，

-O2

添加更多标志，等等）。因此，您可能希望启用所有这些功能，然后逐个删除它们，以查看哪一个（或多个）会影响性能。FWIW，不鼓励手动操作

CMAKE_CXX_FLAGS

变量，您应该改为使用设置这些标志。@squareskittles谢谢您的评论！这正是我想做的。问题是，即使我添加了所有的标志，我仍然看不到任何加速（可能是一个小的加速）。甚至使用

添加编译选项来代替

。

cmake_minimum_required(VERSION 3.14)
project(Filters)

set(CMAKE_CXX_STANDARD 14)
#SET(CMAKE_CXX_FLAGS "-O0 -mavx2 -mbmi2")
#SET(CMAKE_CXX_FLAGS "-O1 -mavx2 -mbmi2")
#SET(CMAKE_CXX_FLAGS "-O2 -mavx2 -mbmi2")
#SET(CMAKE_CXX_FLAGS "-O3 -mavx2 -mbmi2")

#include_directories(.)
include_directories(Bloom_Filter)
include_directories(PD_Filter)
include_directories(Tests)
include_directories(morton)
include_directories(xorfilter)
include_directories(cuckoofilter)

find_package(OpenSSL REQUIRED)
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mavx2 -mbmi2 -DNDEBUG")

add_compile_options(-fauto-inc-dec -fbranch-count-reg -fcombine-stack-adjustments -fcompare-elim -fcprop-registers -fdce -fdefer-pop -fdelayed-branch -fdse -fforward-propagate -fguess-branch-probability -fif-conversion -fif-conversion2 -finline-functions-called-once -fipa-profile -fipa-pure-const -fipa-reference -fmerge-constants -fmove-loop-invariants -fomit-frame-pointer -freorder-blocks -fshrink-wrap -fshrink-wrap-separate -fsplit-wide-types -fssa-backprop -fssa-phiopt -ftree-bit-ccp -ftree-ccp -ftree-ch -ftree-coalesce-vars -ftree-copy-prop -ftree-dce -ftree-dominator-opts -ftree-dse -ftree-forwprop -ftree-fre -ftree-phiprop -ftree-pta -ftree-scev-cprop -ftree-sink -ftree-slsr -ftree-sra -ftree-ter -funit-at-a-time -falign-functions  -falign-jumps -falign-labels  -falign-loops -fcaller-saves -fcode-hoisting -fcrossjumping -fcse-follow-jumps  -fcse-skip-blocks -fdelete-null-pointer-checks -fdevirtualize  -fdevirtualize-speculatively -fexpensive-optimizations -fsplit-loops -fgcse  -fgcse-lm -fhoist-adjacent-loads -finline-functions -finline-small-functions -findirect-inlining -fipa-bit-cp  -fipa-cp  -fipa-icf -fipa-ra  -fipa-sra  -fipa-vrp -fisolate-erroneous-paths-dereference -flra-remat -foptimize-sibling-calls -foptimize-strlen -fpartial-inlining -fpeephole2 -freorder-blocks-algorithm=stc -freorder-blocks-and-partition  -freorder-functions -frerun-cse-after-loop -fschedule-insns  -fschedule-insns2 -fsched-interblock  -fsched-spec -fstore-merging -fstrict-aliasing -fthread-jumps -ftree-builtin-call-dce -ftree-pre -ftree-switch-conversion  -ftree-tail-merge -ftree-vrp -fgcse-after-reload -fipa-cp-clone -floop-interchange -floop-unroll-and-jam -fpeel-loops -fpredictive-commoning -fsplit-loops -fsplit-paths -ftree-loop-distribution -ftree-loop-vectorize -ftree-partial-pre -ftree-slp-vectorize -funswitch-loops -fvect-cost-model -fvect-cost-model=dynamic)
add_executable(
        Filters
        hashutil.h
        Tests/wrappers.hpp
        Tests/tests.hpp Tests/tests.cpp
        Tests/new_tests.hpp Tests/new_tests.cpp
        Tests/printutil.cpp Tests/printutil.hpp
        Bloom_Filter/counting_bloom.h
        Bloom_Filter/simd-block.h
        Bloom_Filter/simd-block-fixed-fpp.h

        PD_Filter/PD.cpp
        PD_Filter/hashutil.hpp PD_Filter/hashutil.cpp
        PD_Filter/hash_table.hpp PD_Filter/hash_table.cpp
        PD_Filter/dict.hpp
        PD_Filter/macros.h

        #        main.cpp
        #        morton/hash_util.h
        #        morton/block.h
        #        morton/bf.h
        #        morton/block.h
        #        morton/compressed_cuckoo_config.h
        #        morton/compressed_cuckoo_filter.h
        #        morton/fixed_point.h
        #        morton/morton_filter.h
        #        morton/morton_sample_configs.h
        #        morton/morton_util.h
        #        morton/test_util.h
        #        morton/util.h
        #        morton/vector_types.h
        Tests/high_load.cpp Tests/high_load.hpp)



target_link_libraries(Filters OpenSSL::SSL)