Bug#693173: gcc-mingw32: float comparison fails assertion only with -std=c99
I also confirm this behavior on x86_64 when compiled with 'gcc -m32 -std=c99'. It seems to happen with 32-bit C99, but not in any other case. -Alan Beadle
Bug#693173: gcc-mingw32: float comparison fails assertion only with -std=c99
I have just now reproduced this bug in Debian Buster x86_64 using
i686-w64-mingw32-gcc-win32 with -std=c99 and wine32, using the
original example above.
Source file foo.c:
#include
float getfloat() { return 12345.6789f; }
int main(void) { assert(12345.6789f == getfloat()); }
Steps to reproduce:
$ i686-w64-mingw32-gcc-win32 foo.c -std=c99
$ wine ./a.exe
Assertion failed: 12345.6789f == getfloat(), file foo.c, line 3
It does not happen when I compile with gcc and run it natively on
linux. It also does not happen if I compile with
x86_64-w64-mingw32-gcc foo.c -std=c99.
Above it was suggested that this might be some kind of expected
behavior. I don't know whether that is the case (seems unlikely to me,
but I don't know). Just reporting that it still happens.
-Alan Beadle
Bug#693173: gcc-mingw32: float comparison fails assertion only with -std=c99
reassign 693173 gcc
thanks
Hi Ben,
On Tue, Nov 13, 2012 at 11:33:01PM +, Ben Golightly wrote:
The following three line C programme generates erroneous output when
compiled with i586-mingw32msvc-gcc -std=c99
#include assert.h
float getfloat() { return 12345.6789f; }
int main(void) { assert(12345.6789f == getfloat()); }
When running the generated binary, the assertion is always triggered.
Steps to reproduce:
$ gcc float.c -o float-linux
$ i586-mingw32msvc-gcc float.c -o float
$ i586-mingw32msvc-gcc float.c -o float-c99 -std=c99
$ ./float-linux // works
$ wine ./float // works
$ wine ./float-c99 // outputs Assertion failed!
The following causes the assertion too, using gcc 4.7.2:
% gcc -std=c99 float.c -o float-linux-c99
% ./float-linux-c99
float-linux-c99: float.c:3: main: Assertion `12345.6789f == getfloat()' failed.
It seems this bug is not specific to gcc-mingw32, but is either really
a bug in gcc or expected behaviour in C99 (I don't know which).
Incidentally, since you're running unstable, you can use the
i686-w64-mingw32 triplet instead of i586-mingw32msvc; the latter will
be going away at some point...
Regards,
Stephen
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Bug#693173: gcc-mingw32: float comparison fails assertion only with -std=c99
Package: gcc-mingw32
Version: 4.6.3-8+7
Severity: important
Dear Maintainer,
The following three line C programme generates erroneous output when
compiled with i586-mingw32msvc-gcc -std=c99
#include assert.h
float getfloat() { return 12345.6789f; }
int main(void) { assert(12345.6789f == getfloat()); }
When running the generated binary, the assertion is always triggered.
Steps to reproduce:
$ gcc float.c -o float-linux
$ i586-mingw32msvc-gcc float.c -o float
$ i586-mingw32msvc-gcc float.c -o float-c99 -std=c99
$ ./float-linux // works
$ wine ./float // works
$ wine ./float-c99 // outputs Assertion failed!
More information:
$ wine --version
wine-1.4.1
Regards,
Ben golightly@googlemail.com
-- System Information:
Debian Release: wheezy/sid
APT prefers testing
APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 3.2.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Versions of packages gcc-mingw32 depends on:
ii binutils-mingw-w64-i686 2.22-7+2
ii g++-mingw-w64-i686 4.6.3-8+7
ii gcc-mingw-w64-base 4.6.3-8+7
ii gcc-mingw-w64-i686 4.6.3-8+7
ii gfortran-mingw-w64-i686 4.6.3-8+7
gcc-mingw32 recommends no packages.
gcc-mingw32 suggests no packages.
-- no debconf information
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