It is a beginer bug, but it would be nice to get a warning in:
#include <stdio.h>
unsigned val1 = 0x10000000, val2 = 0x100;
int main(int argc, char **argv)
{
unsigned long long val3 = val1 * val2;
printf ("val1 = 0x%X, val2 = 0x%X, val3 = 0x%llX, val1*val2 = 0x%llX\n",
val1, val2, val3, (unsigned long long)(val1*val2));
}
Obviously the line printed is:
val1 = 0x10000000, val2 = 0x100, val3 = 0x0, val1*val2 = 0x0
(compiled with "gcc -w -Wall -O2 tmp.c" you get no warning)
Got bitten yesterday by gcc-4.4.3, reproduced today on gcc version 4.1.2.
--
Summary: Warning "u64 = u32 * u32;" - i.e. not casting one u32 to
u64
Product: gcc
Version: 4.4.3
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: etienne_lorrain at yahoo dot fr
GCC build triplet: i686-pc-cygwin
GCC host triplet: i686-pc-cygwin
GCC target triplet: i686-pc-cygwin
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42935
