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=16000000UL -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 data bss dec hex filename
850 0 2400 3250 cb2
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?
