[Bug c++/59394] New: Unused code generated
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59394 Bug ID: 59394 Summary: Unused code generated Product: gcc Version: 4.8.2 Status: UNCONFIRMED Severity: major Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: smal.root at gmail dot com Target: AVR Created attachment 31385 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31385&action=edit source code GCC: avr-gcc -v Using built-in specs. COLLECT_GCC=avr-gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/avr/4.8.2/lto-wrapper Target: avr Configured with: /build/avr-gcc/src/gcc-4.8.2/configure --disable-cloog-version-check --disable-install-libiberty --disable-libssp --disable-libstdcxx-pch --disable-libunwind-exceptions --disable-linker-build-id --disable-nls --disable-werror --enable-__cxa_atexit --enable-checking=release --enable-clocale=gnu --enable-cloog-backend=isl --enable-gnu-unique-object --enable-gold --enable-languages=c,c++ --enable-ld=default --enable-lto --enable-plugin --enable-shared --infodir=/usr/share/info --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --prefix=/usr --target=avr --with-as=/usr/bin/avr-as --with-gnu-as --with-gnu-ld --with-ld=/usr/bin/avr-ld --with-plugin-ld=ld.gold --with-system-zlib Thread model: single gcc version 4.8.2 (GCC) OS: Arch Linux Linux 3.12.0-1-ARCH #1 SMP PREEMPT Wed Nov 6 09:06:27 CET 2013 x86_64 GNU/Linux Command line: avr-gcc -Wall -mmcu=atxmega64a3 -DF_CPU=1600UL -mno-interrupts -Os -pedantic-errors -pedantic -std=c++11 -Wfatal-errors -Wall -I/usr/avr/include -c main.cpp -o obj/Release/main.o main.cpp: In function 'int main()': main.cpp:55:21: warning: variable 'tval32' set but not used [-Wunused-but-set-variable] volatile uint32_t tval32; ^ avr-g++ -o bin/Release/lambda_test.elf obj/Release/main.o -mmcu=atxmega64a3 -Wl,-Map=bin/Release/lambda_test.map,--cref Output size is 7,92 KB Running project post-build steps avr-size bin/Release/lambda_test.elf text databssdechexfilename 850 0 2400 3250cb2 bin/Release/lambda_test.elf avr-objdump -h -S bin/Release/lambda_test.elf > bin/Release/lambda_test.lss Process terminated with status 0 (0 minutes, 0 seconds) 0 errors, 1 warnings (0 minutes, 0 seconds) Source file: attached main.cpp Generated assembly: attached lambda_test.lss Problem. A. As you can see in generated assembly: 1. function Sort_OldStyle(_Z13Sort_OldStylev) contain(as inline) functions Sort and Sort_OldStyle_Internal 2. function Sort_NewStyle(_Z13Sort_NewStylev) contain(as inline) functions Sort and lambda-expression B. But also generated code contain unneded: 1. function Sort(_Z4SortPV5SPairS1_PFvRS0_E) 2. function Sort_OldStyle_Internal(_Z22Sort_OldStyle_InternalRV5SPair) 3. lambda-expression(_ZZ13Sort_NewStylevENUlRV5SPairE_4_FUNES1_) Why gcc include functions from B-list if they already exist in functions of list A? Also why gcc use inline for function Sort and don't use call with -Os used?
[Bug c++/59394] Unused code generated
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59394 --- Comment #1 from smalcom --- Created attachment 31386 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31386&action=edit generated assembly
[Bug c++/84814] New: Type of arithmetic expression
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84814 Bug ID: 84814 Summary: Type of arithmetic expression Product: gcc Version: 7.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: smal.root at gmail dot com Target Milestone: --- Created attachment 43620 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43620&action=edit Project archive File: main.cpp, line: 20. When used variant > if((curtime - LastTime) >= Request) then we get following assembly code (file: type_test_wo_conv.lss): > 8000260: 8806ldrhr6, [r0, #0] > 8000262: 7825ldrbr5, [r4, #0] > 8000264: b292uxthr2, r2 > 8000266: 1b92subsr2, r2, r6 > 8000268: 42aacmp r2, r5 as you can see "subs" result is not converted to uint16_t, but must. Because both arguments of subtraction has same type: "— Otherwise, the integral promotions (4.5) shall be performed on both operands. Then the following rules shall be applied to the promoted operands: — If both operands have the same type, no further conversion is needed." As result - arguments of "cmp" is invalid uint32_t values. If we use additional "manual" type conversion for expression > if((uint16_t)(curtime - LastTime) >= Request) then we get right result: > 8000260: 8806ldrhr6, [r0, #0] > 8000262: 7825ldrbr5, [r4, #0] > 8000264: 1b92subsr2, r2, r6 > 8000266: b292uxthr2, r2 > 8000268: 42aacmp r2, r5 after "subs" result is converted to uint16_t.
[Bug c++/79600] New: [c++11] reinterpret_cast not working in enum class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79600 Bug ID: 79600 Summary: [c++11] reinterpret_cast not working in enum class Product: gcc Version: 7.0.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: smal.root at gmail dot com Target Milestone: --- Created attachment 40774 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40774&action=edit source code New compiler do not want to assign value to member of enum class and show error: 1.cpp: In function 'int main()': 1.cpp:14:43: error: reinterpret_cast from integer to pointer EnumMember = reinterpret_cast(&TEST_MACROS) ^ 1.cpp:14:43: error: 'reinterpret_cast(2048)' is not a constant expression 1.cpp:14:58: error: enumerator value for 'EnumMember' is not an integer constant EnumMember = reinterpret_cast(&TEST_MACROS) But value successfully assigned for regular variable. avr-gcc-4.9.4 - compilation successful avr-gcc-5.4.0 - compilation successful avr-gcc-6.3.0 - compilation error avr-gcc-7.0.1-20170219 - compilation error I'll attach *.ii files for every gcc version. Build string: avr-g++ -save-temps -std=c++11 -Wall -Os -pedantic -mmcu=atxmega128a3u -c 1.cpp -o 1.o && avr-g++ -std=c++11 -Wall -Os -mmcu=atxmega128a3u 1.o -o 1 Information about compilers 1. Using built-in specs. COLLECT_GCC=avr-gcc COLLECT_LTO_WRAPPER=/opt/toolchain/avr/libexec/gcc/avr/4.9.4/lto-wrapper Target: avr Configured with: ../gcc-4.9.4/configure --prefix=/opt/toolchain/avr --target=avr --disable-nls --enable-languages=c,c++ --disable-libssp --enable-lto --with-isl Thread model: single gcc version 4.9.4 (GCC) 2. 5.4.0 Using built-in specs. Reading specs from /opt/toolchain/avr_5/lib/gcc/avr/5.4.0/device-specs/specs-avr2 COLLECT_GCC=avr-gcc COLLECT_LTO_WRAPPER=/opt/toolchain/avr_5/libexec/gcc/avr/5.4.0/lto-wrapper Target: avr Configured with: ../gcc-5.4.0/configure --prefix=/opt/toolchain/avr_5 --disable-nls --disable-shared --target=avr --disable-install-libiberty --disable-libssp --disable-libstdcxx-pch --disable-libunwind-exceptions --disable-linker-build-id --disable-werror --disable-__cxa_atexit --enable-checking=release --enable-clocale=gnu --enable-gnu-unique-object --enable-gold --enable-languages=c,c++ --enable-ld=default --enable-lto --enable-plugin --enable-shared --with-gnu-as --with-gnu-ld --with-plugin-ld=ld.gold --with-system-zlib --with-isl --enable-gnu-indirect-function Thread model: single gcc version 5.4.0 (GCC) 3. 6.3.0 Using built-in specs. Reading specs from /opt/toolchain/avr_6/lib/gcc/avr/6.3.0/device-specs/specs-avr2 COLLECT_GCC=avr-gcc COLLECT_LTO_WRAPPER=/opt/toolchain/avr_6/libexec/gcc/avr/6.3.0/lto-wrapper Target: avr Configured with: ../gcc-6.3.0/configure --prefix=/opt/toolchain/avr_6 --disable-nls --disable-shared --target=avr --disable-install-libiberty --disable-libssp --disable-libstdcxx-pch --disable-libunwind-exceptions --disable-linker-build-id --disable-werror --disable-__cxa_atexit --enable-checking=release --enable-clocale=gnu --enable-gnu-unique-object --enable-gold --enable-languages=c,c++ --enable-ld=default --enable-lto --enable-plugin --enable-shared --with-gnu-as --with-gnu-ld --with-plugin-ld=ld.gold --with-system-zlib --with-isl --enable-gnu-indirect-function Thread model: single gcc version 6.3.0 (GCC) 4. trunk Using built-in specs. Reading specs from /opt/toolchain/avr_trunk/lib/gcc/avr/7.0.1/device-specs/specs-avr2 COLLECT_GCC=avr-gcc COLLECT_LTO_WRAPPER=/opt/toolchain/avr_trunk/libexec/gcc/avr/7.0.1/lto-wrapper Target: avr Configured with: ../gcc_trunk/configure --prefix=/opt/toolchain/avr_trunk --disable-nls --disable-shared --target=avr --enable-languages=c,c++ --enable-lto --enable-plugin --with-isl Thread model: single gcc version 7.0.1 20170219 (experimental) (GCC) Why do not to use version 4 or 5? )) avr-gcc-4.9.4 generate file with size ~58kB. Nice, but not working. avr-gcc-5.3.0 generate file with size ~74kB. Uncool.
[Bug c++/79600] [c++11] reinterpret_cast not working in enum class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79600 --- Comment #1 from smalcom --- Created attachment 40775 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40775&action=edit ii from 4.9.4
[Bug c++/79600] [c++11] reinterpret_cast not working in enum class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79600 --- Comment #2 from smalcom --- Created attachment 40776 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40776&action=edit ii from 6.3.0
[Bug c++/79600] [c++11] reinterpret_cast not working in enum class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79600 --- Comment #3 from smalcom --- Created attachment 40777 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40777&action=edit ii from 7.0.1
[Bug c++/79600] [c++11] reinterpret_cast not working in enum class
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79600 --- Comment #5 from smalcom --- Second error string... I'm stupid. Thanks for help. So, old compilers just kinder?
[Bug middle-end/59394] Unused code generated
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59394 --- Comment #5 from smalcom --- Created attachment 52049 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52049&action=edit Generated assembly when using "gc-section". avr-gcc-10.2
[Bug middle-end/59394] Unused code generated
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59394 --- Comment #6 from smalcom --- Created attachment 52050 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52050&action=edit Generated assembly when using "LTO". avr-gcc-10.2 (In reply to Andrew Pinski from comment #4) > If I use -Wl,--gc-sections -ffunction-sections, then all of the unused > (non-static) functions are removed. > > Also -flto is able to optimize it too. I confirm that: 1. With set "-Wl,--gc-sections -ffunction-sections" output file do not contain unused functions (attached gcsec.lss). 2. With "-flto" all functions are inlined and present only used code (attached lto.lss). Tested using gcc-10: avr-gcc -v Using built-in specs. Reading specs from /mnt/stor5/opt/сборка/avr-10.2.0/bin/../lib/gcc/avr/10.2.0/device-specs/specs-avr2 COLLECT_GCC=avr-gcc COLLECT_LTO_WRAPPER=/mnt/stor5/opt/сборка/avr-10.2.0/bin/../libexec/gcc/avr/10.2.0/lto-wrapper Target: avr Configured with: ../configure --prefix=/opt/toolchain/avr-10.2.0 --target=avr --enable-languages=c,c++ --disable-nls --disable-libssp --with-dwarf2 Thread model: single Supported LTO compression algorithms: zlib zstd gcc version 10.2.0 (GCC) Great. Thanks!
