[Bug target/63661] [4.9/5 Regression] -O2 miscompiles on OSX 10.10 Yosemite
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63661 mednafen at gmail dot com changed: What|Removed |Added CC||mednafen at gmail dot com --- Comment #19 from mednafen at gmail dot com --- Created attachment 33870 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33870&action=edit Simplified testcase. Simplified testcase, tested to be broken on x86_64 Linux. $ /usr/local/gcc-4.9.2/bin/gcc -O2 -fpic -o testcase-alt testcase-alt.c && ./testcase-alt A: 0x7fffd8416f60 B: 0x4014 5 $ /usr/local/gcc-4.9.2/bin/gcc -O2 -fpic -mtune=nehalem -o testcase-alt testcase-alt.c && ./testcase-alt A: 0x7fffc9fb1730 B: 0x7fffc9fb1730 6.95331e-310 Aborted
[Bug target/63661] [4.9/5 Regression] -O2 miscompiles on OSX 10.10 Yosemite
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63661 --- Comment #18 from Martin Jambor --- (In reply to Jakub Jelinek from comment #14) > Started with r204698 , you can use -O2 -fpic -mtune=corei7 in compilers that > don't grok -mtune=nehalem. So it's probably mine. I will take a look but please be patient, it may take a week or probably two.
[Bug target/63661] [4.9/5 Regression] -O2 miscompiles on OSX 10.10 Yosemite
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63661 Volker Braun changed: What|Removed |Added Known to fail||4.9.2 --- Comment #17 from Volker Braun --- Bug is still in gcc 4.9.2
[Bug target/63661] [4.9/5 Regression] -O2 miscompiles on OSX 10.10 Yosemite
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63661 Jakub Jelinek changed: What|Removed |Added Target Milestone|4.9.2 |4.9.3 --- Comment #16 from Jakub Jelinek --- GCC 4.9.2 has been released.
[Bug target/63661] [4.9/5 Regression] -O2 miscompiles on OSX 10.10 Yosemite
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63661
--- Comment #15 from Jakub Jelinek ---
Slightly reduced testcase:
static void
foo (double a, double q, double xx, double *ff, double *gx, int e, int ni)
{
int ii, nn;
double g1 = *gx;
ff[ni] = xx;
if (e == 0)
{
for (ii = 0; ii < ni; ii++)
{
nn = 100 - ii - 1;
ff[ni - ii - 1]
= -1.0 / ((4 * (nn + 1) * (nn + 1) - a) / q + ff[ni - ii]);
}
}
else
{
for (ii = 0; ii < ni; ii++)
{
nn = 100 - ii - 1;
ff[ni - ii - 1]
= -1.0 / (((2 * nn + 1) * (2 * nn + 1) - a) / q + ff[ni - ii]);
}
}
*gx = ff[0] - g1;
}
int
bar (int order, double q, double a, double c[])
{
int ni, nn, i, e;
double eps, g1, g2, x1, x2, e1, e2, de, xh, s, ratio, ff[100];
eps = 1e-10;
c[0] = 1.0;
e = 0;
if (order % 2 != 0)
e = 1;
if (q == 0.0)
{
for (i = 0; i < 100; i++)
c[i] = 0.0;
c[(order - 1) / 2] = 1.0;
return 0;
}
if (order < 5)
{
nn = 0;
s = 0.0;
if (e == 0)
ratio = (a - 4) / q;
else
ratio = (a - 1 - q) / q;
}
else
{
if (e == 0)
{
c[1] = (a - 4) / q;
s = 2 * c[0] + 4 * c[1];
for (i = 2; i < order / 2; i++)
{
c[i] = (a - 4 * i * i) / q * c[i - 1] - c[i - 2];
s += 2 * (i + 1) * c[i];
}
}
else
{
c[1] = (a - 1) / q + 1;
s = c[0] + 3 * c[1];
for (i = 2; i < order / 2 + 1; i++)
{
c[i] = (a - (2 * i - 1) * (2 * i - 1)) / q * c[i - 1] - c[i - 2];
s += (2 * (i + 1) - 1) * c[i];
}
}
nn = i - 1;
ratio = c[nn] / c[nn - 1];
}
ni = 100 - nn - 1;
if (e == 0)
x1 = -q / (4.0 * (100 + 1.0) * (100 + 1.0));
else
x1 = -q / ((2.0 * 100 + 1.0) * (2.0 * 100 + 1.0));
g1 = ratio;
foo (a, q, x1, ff, &g1, e, ni);
x2 = g1;
g2 = ratio;
while (1)
{
__builtin_printf ("loop %g\n", g2);
e1 = g1 - x1;
e2 = g2 - x2;
de = e1 - e2;
if (__builtin_fabs (de) < eps)
break;
xh = (e1 * x2 - e2 * x1) / de;
x1 = x2;
g1 = g2;
x2 = xh;
g2 = ratio;
foo (a, q, x2, ff, &g2, e, ni);
}
s += 2 * (nn + 1) * c[nn];
for (i = nn + 1; i < 100; i++)
{
c[i] = ff[i - nn - 1] * c[i - 1];
s += 2 * (i + 1) * c[i];
if (__builtin_fabs (c[i]) < 1e-20)
for (; i < 100;)
c[i++] = 0.0;
}
for (i = 0; i < 100; i++)
c[i] /= s;
return 0;
}
int
main ()
{
double c[100];
bar (1, 5.0, -5.790080598637771, c);
return 0;
}
[Bug target/63661] [4.9/5 Regression] -O2 miscompiles on OSX 10.10 Yosemite
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63661 Jakub Jelinek changed: What|Removed |Added CC||jakub at gcc dot gnu.org, ||jamborm at gcc dot gnu.org, ||vmakarov at gcc dot gnu.org --- Comment #14 from Jakub Jelinek --- Started with r204698 , you can use -O2 -fpic -mtune=corei7 in compilers that don't grok -mtune=nehalem.
[Bug target/63661] [4.9/5 Regression] -O2 miscompiles on OSX 10.10 Yosemite
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63661 Richard Biener changed: What|Removed |Added Known to work||4.8.3 Target Milestone|--- |4.9.2 Summary|-O2 miscompiles on OSX |[4.9/5 Regression] -O2 |10.10 Yosemite |miscompiles on OSX 10.10 ||Yosemite Known to fail||4.9.1, 5.0 --- Comment #13 from Richard Biener --- 4.8 doesn't know nehalem but works with -mtune=native (where 4.9 and 5 break).
