https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113679
Bug ID: 113679
Summary: long long minus double with gcc -m32 produces
different results than other compilers or gcc -m64
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: dilyan.palauzov at aegee dot org
Target Milestone: ---
diff.c is:
#include <stdio.h>
int main(void) {
long long l = 9223372036854775806;
double d = 9223372036854775808.0;
printf("%f\n", (double)l - d);
return 0;
}
With gcc (GCC) 13.2.1 20231205 (Red Hat 13.2.1-6), gcc (Ubuntu
9.4.0-1ubuntu1~20.04.2) 9.4.0, clang 16.0.4 and clang 17.0.5:
$ gcc -m64 -o diff diff.c && ./diff
0.000000
$ gcc -m32 -o diff diff.c && ./diff
-2.000000
$ clang -m64 -o diff diff.c && ./diff
0.000000
$ clang -m32 -o diff diff.c && ./diff
0.000000
With cl.exe 19.29.3015319.29.30153 (first is x84 - 32 bit, second is 64 bit)
C:\> CALL "C:\Program Files (x86)\Microsoft Visual
Studio\2019\Community\VC\Auxiliary\Build\vcvarsall.bat" x86 10.0.17763.0
C:\> cl diff.c >nul 2>nul & .\diff.exe
0.000000
C:\> CALL "C:\Program Files (x86)\Microsoft Visual
Studio\2019\Community\VC\Auxiliary\Build\vcvarsall.bat" amd64 10.0.17763.0
C:\> cl diff.c >nul 2>nul & .\diff.exe
0.000000
gcc -m32 produces a different result, compared to gcc -m64, clang 17 (32 and
64bit), and MSCV Visual Studio 2019 (32 and 64bit).
