[Bug c/57531] lvalue required with comma operator
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531
vijay Nag vijunag at gmail dot com changed:
What|Removed |Added
Component|c++ |c
Severity|normal |critical
--- Comment #2 from vijay Nag vijunag at gmail dot com ---
Sorry for the confusion. Please try the unit test case below
#include stdio.h
/*remove assert in production*/
#define ASSERT(x) (void)0
#define GET_VALUE_A(value) ((value)-version == 1 ? ASSERT(value), (value)-b :
(value)-a)
struct Lvalue {
int version;
int a;
int b;
};
int main()
{
struct Lvalue lvalue = {};
lvalue.version = 1;
GET_VALUE_A(lvalue) = 5;
}
i686-pc-linux-gnu-gcc -c ternary.c
ternary.c: In function ‘main’:
ternary.c:19:24: error: lvalue required as left operand of assignment
i686-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=~/tools/bintools/linux-x86/gcc/201302221200/bin/i686-pc-linux-gnu-gcc-wrapped
COLLECT_LTO_WRAPPER=~/tools/bintools/linux-x86/gcc/201302221200/libexec/gcc/i686-pc-linux-gnu/4.7.2/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../../gcc/configure --build=amd64-pc-linux-gnu
--host=amd64-pc-linux-gnu --target=i686-pc-linux-gnu --enable-languages=c,c++
--prefix=~tools/bintools/linux-x86/gcc/201302221200 --enable-shared
--with-headers=/tmp/201302221200/new_header/ --disable-libquadmath
--disable-libgomp --disable-libssp --disable-libmudflap --disable-libitm
--with-fast-fixincludes --enable-threads --site=starent --with-gnu-as
--with-gnu-ld
Thread model: posix
gcc version 4.7.2 (GCC)
i586-pc-linux-gnu-gcc -c ternary.c
i586-pc-linux-gnu-gcc -v
Reading specs from
~/tools/bintools/linux-x86/gcc/200608191248/lib/gcc-lib/i586-pc-linux-gnu/3.3.6/specs
Configured with: ../../gcc/configure --build=i686-linux --host=i686-linux
--target=i586-pc-linux-gnu --enable-languages=c,c++
--prefix=~/tools/bintools/linux-x86/gcc/200608191248 --enable-shared
--with-headers=/localdisk/tmp/x86-linux/include --with-fast-fixincludes
--enable-threads --site=starent --with-gnu-as --with-gnu-ld
Thread model: posix
gcc version 3.3.6
[Bug c/57531] lvalue required with comma operator
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531
--- Comment #3 from vijay Nag vijunag at gmail dot com ---
(In reply to vijay Nag from comment #2)
Sorry for the confusion. Please try the unit test case below
#include stdio.h
/*remove assert in production*/
#define ASSERT(x) (void)0
#define GET_VALUE_A(value) ((value)-version == 1 ? ASSERT(value),
(value)-b : (value)-a)
struct Lvalue {
int version;
int a;
int b;
};
int main()
{
struct Lvalue lvalue = {};
lvalue.version = 1;
GET_VALUE_A(lvalue) = 5;
}
i686-pc-linux-gnu-gcc -c ternary.c
ternary.c: In function ‘main’:
ternary.c:19:24: error: lvalue required as left operand of assignment
i686-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=~/tools/bintools/linux-x86/gcc/201302221200/bin/i686-pc-linux-
gnu-gcc-wrapped
COLLECT_LTO_WRAPPER=~/tools/bintools/linux-x86/gcc/201302221200/libexec/gcc/
i686-pc-linux-gnu/4.7.2/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../../gcc/configure --build=amd64-pc-linux-gnu
--host=amd64-pc-linux-gnu --target=i686-pc-linux-gnu
--enable-languages=c,c++ --prefix=~tools/bintools/linux-x86/gcc/201302221200
--enable-shared --with-headers=/tmp/201302221200/new_header/
--disable-libquadmath --disable-libgomp --disable-libssp
--disable-libmudflap --disable-libitm --with-fast-fixincludes
--enable-threads --site=starent --with-gnu-as --with-gnu-ld
Thread model: posix
gcc version 4.7.2 (GCC)
i586-pc-linux-gnu-gcc -c ternary.c
i586-pc-linux-gnu-gcc -v
Reading specs from
~/tools/bintools/linux-x86/gcc/200608191248/lib/gcc-lib/i586-pc-linux-gnu/3.
3.6/specs
Configured with: ../../gcc/configure --build=i686-linux --host=i686-linux
--target=i586-pc-linux-gnu --enable-languages=c,c++
--prefix=~/tools/bintools/linux-x86/gcc/200608191248 --enable-shared
--with-headers=/localdisk/tmp/x86-linux/include --with-fast-fixincludes
--enable-threads --site=starent --with-gnu-as --with-gnu-ld
Thread model: posix
gcc version 3.3.6
[Bug c/57531] lvalue required with comma operator
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531 Paolo Carlini paolo.carlini at oracle dot com changed: What|Removed |Added Severity|critical|normal
[Bug c/57531] lvalue required with comma operator
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531 vijay Nag vijunag at gmail dot com changed: What|Removed |Added CC||vijunag at gmail dot com Severity|normal |major
[Bug c++/57531] lvalue required with comma operator
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531 Andrew Pinski pinskia at gcc dot gnu.org changed: What|Removed |Added Component|c |c++ Severity|major |normal --- Comment #4 from Andrew Pinski pinskia at gcc dot gnu.org --- I think the problem is the comma operator causes it to be a rvalue. In that ((void)0, x) is considered rvalue rather than what you want as a lvalue. Note C does not have ?: as lvalues so this cannot apply to C; only C++.
[Bug c++/57531] lvalue required with comma operator
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531 --- Comment #5 from vijay Nag vijunag at gmail dot com --- (In reply to Andrew Pinski from comment #4) I think the problem is the comma operator causes it to be a rvalue. In that ((void)0, x) is considered rvalue rather than what you want as a lvalue. Note C does not have ?: as lvalues so this cannot apply to C; only C++. Why did it work with gcc-3.3.6 ? Any revisions in standard ?
[Bug c++/57531] lvalue required with comma operator
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531 Andreas Schwab sch...@linux-m68k.org changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #6 from Andreas Schwab sch...@linux-m68k.org --- This GCC extension has been removed in 4.0.
[Bug c/57531] lvalue required with comma operator
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531 vijay Nag vijunag at gmail dot com changed: What|Removed |Added Severity|normal |critical
[Bug c++/57531] lvalue required with comma operator
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531 Andrew Pinski pinskia at gcc dot gnu.org changed: What|Removed |Added Severity|critical|normal --- Comment #1 from Andrew Pinski pinskia at gcc dot gnu.org --- Your small testcase works for me both in 4.7.0 and 4.9.0 (20130422). Your lvalue.cpp does not correspond to your testcase your placed in the bug report either.
