Depending on the sequencing of comparisons in an if statement, the code generated will be incomplete or correct.
In the function get_element_0, the check for (p_this != NULL) is NOT translated into machine code.
In the function get_element_1, the check for (p_this != NULL) IS translated into machine code.
/*--------------------------------------------------------------------------*/
#define NULL ((void *)0)
typedef struct s struct_t;
struct s
{
struct_t * p_next;
};
/*--------------------------------------------------------------------------*/
struct_t * get_element_0 (struct_t * p_chain,
struct_t * p_element)
{
struct_t * p_this;
p_this = p_chain;
while ((p_this->p_next != p_element) &&
(p_this != NULL ))
{
p_this = p_this->p_next;
}
return (p_this);
}
/*--------------------------------------------------------------------------*/
struct_t * get_element_1 (struct_t * p_chain,
struct_t * p_element)
{
struct_t * p_this;
p_this = p_chain;
while ((p_this != NULL ) &&
(p_this->p_next != p_element))
{
p_this = p_this->p_next;
}
return (p_this);
}
/*--------------------------------------------------------------------------*/
Invoking GCC with the -v option gives
compiling GCC error.c...
COLLECT_GCC=C:\Programs\GCCARM\bin\arm-none-eabi-gcc
Target: arm-none-eabi
Configured with: /home/build/work/GCC-4-9-build/src/gcc/configure --build=i686-linux-gnu --host=i686-w64-mingw32 --target=arm-none-eabi --prefix=/home/build/work/GCC-4-9-build/install-mingw --libexecdir=/home/build/work/GCC-4-9-build/install-mingw/lib --infodir=/home/build/work/GCC-4-9-build/install-mingw/share/doc/gcc-arm-none-eabi/info --mandir=/home/build/work/GCC-4-9-build/install-mingw/share/doc/gcc-arm-none-eabi/man --htmldir=/home/build/work/GCC-4-9-build/install-mingw/share/doc/gcc-arm-none-eabi/html --pdfdir=/home/build/work/GCC-4-9-build/install-mingw/share/doc/gcc-arm-none-eabi/pdf --enable-languages=c,c++ --disable-decimal-float --disable-libffi --disable-libgomp --disable-libmudflap --disable-libquadmath --disable-libssp --disable-libstdcxx-pch --disable-nls --disable-shared --disable-threads --disable-tls --with-gnu-as --with-gnu-ld --with-headers=yes --with-newlib --with-python-dir=share/gcc-arm-none-eabi --with-sysroot=/home/build/work/GCC-4-9-build/install-mingw/arm-none-eabi --with-libiconv-...
Thread model: single
COLLECT_GCC_OPTIONS='-c' '-mcpu=cortex-m4' '-mthumb' '-gdwarf-2' '-MD' '-O' '-mapcs-frame' '-I' './arm' '-I' './beacon' '-I' './common' '-I' './control' '-I' './mmi' '-I' './sensors' '-I' './seos' '-I' './sysdef' '-I' './usb' '-I' './wlink' '-I' 'C:/Programs/Keil/ARM/Pack/Keil/SAM4_DFP/1.4.0/Device/Include/SAM4S' '-I' 'C:/Programs/Keil/ARM/Pack/ARM/CMSIS/4.5.0/CMSIS/Include' '-mcpu=cortex-m4' '-gdwarf-2' '-Os' '-fno-common' '-Wall' '-no-integrated-cpp' '-g' '-mno-unaligned-access' '-v' '-I' 'C:/Users/Meier/BNGSVN/trunk/targets/BNGPT2/RTE' '-I' 'C:/Programs/Keil/ARM/PACK/Keil/SAM4_DFP/1.4.0/Device/Include/SAM4S' '-I' 'C:/Programs/Keil/ARM/CMSIS/Include' '-I' 'C:/Programs/GCCARM/arm-none-eabi/include' '-I' 'C:/Programs/GCCARM/lib/gcc/arm-none-eabi/4.9.3/include' '-I' 'C:/Programs/GCCARM/arm-none-eabi/include/c++/4.9.3' '-I' 'C:/Programs/GCCARM/arm-none-eabi/include/c++/4.9.3/arm-none-eabi' '-D' '__UVISION_VERSION=518' '-D' '__GCC' '-D' '__GCC_VERSION=493' '-D' '__SAM4S8C__' '-D' 'CONTEXT_DEVICE=1' '-D' 'CONTEXT...
c:/programs/gccarm/bin/../lib/gcc/arm-none-eabi/4.9.3/cc1.exe -E -quiet -v -I ./arm -I ./beacon -I ./common -I ./control -I ./mmi -I ./sensors -I ./seos -I ./sysdef -I ./usb -I ./wlink -I C:/Programs/Keil/ARM/Pack/Keil/SAM4_DFP/1.4.0/Device/Include/SAM4S -I C:/Programs/Keil/ARM/Pack/ARM/CMSIS/4.5.0/CMSIS/Include -I C:/Users/Meier/BNGSVN/trunk/targets/BNGPT2/RTE -I C:/Programs/Keil/ARM/PACK/Keil/SAM4_DFP/1.4.0/Device/Include/SAM4S -I C:/Programs/Keil/ARM/CMSIS/Include -I C:/Programs/GCCARM/arm-none-eabi/include -I C:/Programs/GCCARM/lib/gcc/arm-none-eabi/4.9.3/include -I C:/Programs/GCCARM/arm-none-eabi/include/c++/4.9.3 -I C:/Programs/GCCARM/arm-none-eabi/include/c++/4.9.3/arm-none-eabi -imultilib armv7e-m -iprefix c:\programs\gccarm\bin\../lib/gcc/arm-none-eabi/4.9.3/ -isysroot c:\programs\gccarm\bin\../arm-none-eabi -MD ./arm/obj/gcc error.d -MQ ./arm/obj/gcc error.o -D__USES_INITFINI__ -D __UVISION_VERSION=518 -D __GCC -D __GCC_VERSION=493 -D __SAM4S8C__ -D CONTEXT_DEVICE=1 -D CONTEXT_BDE=0 -D ARM_MATH_CM...
ignoring duplicate directory "c:/programs/gccarm/lib/gcc/../../lib/gcc/arm-none-eabi/4.9.3/include"
ignoring nonexistent directory "c:\programs\gccarm\bin\../arm-none-eabi/home/build/work/GCC-4-9-build/install-mingw/lib/gcc/arm-none-eabi/4.9.3/../../../../include"
