https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80426
Bug ID: 80426
Summary: Wrong constant folding
Product: gcc
Version: 7.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC 7.0.1 for x86_64 miscompiles the following code.
% cat test.c
#define INT_MAX 0x7fffffff
#define INT_MIN (-INT_MAX-1)
int x;
int main (void)
{
volatile int a = 0;
volatile int b = -INT_MAX;
int j;
for( j = 0; j < 18; j += 1 ) {
x = ( (a == 0) != (b - (int)(INT_MIN) ) );
}
if (x != 0) __builtin_abort();
return 0;
}
% gcc-7.0 test.c -O2
% ./a.out
zsh: abort (core dumped) ./a.out
% gcc-7.0 test.c -O3
% ./a.out
zsh: abort (core dumped) ./a.out
% gcc-7.0 test.c -Os
% ./a.out
zsh: abort (core dumped) ./a.out
% gcc-7.0 -v
Using built-in specs.
COLLECT_GCC=gcc-7.0
COLLECT_LTO_WRAPPER=/home/cappie/opt/gcc-7.0.1/libexec/gcc/x86_64-pc-linux-gnu/7.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure --prefix=/home/cappie/opt/gcc-7.0.1 --disable-nls
--disable-multilib --program-suffix=-7.0 --enable-languages=c
Thread model: posix
gcc version 7.0.1 20170330 (experimental) (GCC)
