https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71608
Bug ID: 71608
Summary: Wrong constant folding
Product: gcc
Version: 7.0
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 7.0.0 for x86_64 miscompiles the following code.
% cat test.c
int x = 0x40000000;
int main (void)
{
int t = - 0x7FFFFFFF - ( -2 * x ) ;
if (t != 1) __builtin_abort();
return 0;
}
% gcc-7.0 test.c -O3
% ./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-7.0.0/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure --prefix=/home/cappie/opt/gcc-7.0.0 --disable-nls
--disable-multilib --program-suffix=-7.0 --enable-languages=c
Thread model: posix
gcc version 7.0.0 20160621 (experimental) (GCC)
Reproduces on gcc-4.3.6 or later with -O3.
Also reproduces on 5.1.0 or later with -O1.
