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[Bug tree-optimization/69760] [4.9/5/6 Regression] Wrong 64-bit memory address caused by an unneeded overflowing 32-bit integer multiplication on x86_64 under -O2 and -O3 code optimization
- From: "jakub at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 23 Feb 2016 10:39:06 +0000
- Subject: [Bug tree-optimization/69760] [4.9/5/6 Regression] Wrong 64-bit memory address caused by an unneeded overflowing 32-bit integer multiplication on x86_64 under -O2 and -O3 code optimization
- Auto-submitted: auto-generated
- References: <bug-69760-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69760
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Adjusted testcase that only needs 305MB virtual.
/* PR tree-optimization/69760 */
/* { dg-do run { target { { *-*-linux* *-*-gnu* } && mmap } } } */
/* { dg-options "-O2" } */
#include <unistd.h>
#include <sys/mman.h>
__attribute__((noinline, noclone)) void
test_func (double *a, int L, int m, int n, int N)
{
int i, k;
for (i = 0; i < N; i++)
{
k = i - m;
if (k >= 0 && k < n)
a[L * k] = 0.0;
}
}
int
main ()
{
char *p;
int L, m, n, N;
long l;
L = 10000000;
n = 4;
N = 100 * n;
long pgsz = sysconf(_SC_PAGESIZE);
if (pgsz < sizeof (double) || pgsz > L * sizeof (double))
return 0;
p = mmap ((void *) 0, L * n * sizeof (double), PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (p == MAP_FAILED)
return 0;
if (mprotect (p, pgsz, PROT_READ | PROT_WRITE))
return 0;
l = (L * sizeof (double)) / pgsz * pgsz;
if (mprotect (p + l, pgsz, PROT_READ | PROT_WRITE))
return 0;
l = (2 * L * sizeof (double)) / pgsz * pgsz;
if (mprotect (p + l, pgsz, PROT_READ | PROT_WRITE))
return 0;
l = (3 * L * sizeof (double)) / pgsz * pgsz;
if (mprotect (p + l, pgsz, PROT_READ | PROT_WRITE))
return 0;
for (m = 0; m < N; m += n)
test_func ((double *) p, L, m, n, N);
return 0;
}