[Bug rtl-optimization/89225] New: [9 Regression] LRA hang on ppc64le compiling glibc starting with r268404
jakub at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Wed Feb 6 15:16:00 GMT 2019
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89225
Bug ID: 89225
Summary: [9 Regression] LRA hang on ppc64le compiling glibc
starting with r268404
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
Target Milestone: ---
The following testcase hangs in LRA with -O2 -fstack-protector-strong
-mlong-double-128 on powerpc64le-linux.
extern long double foo (long double);
extern double bar (double);
typedef long long int64_t;
typedef unsigned long long uint64_t;
typedef union { int64_t i[2]; long double x; double d[2]; } mynumber;
static const double t512 = 0x1p512, tm256 = 0x1p-256, two54 = 0x1p54, twom54 =
0x1p-54;
long double
foo (long double x)
{
static const long double big = 134217728.0, big1 = 134217729.0;
long double t, s, i;
mynumber a, c;
uint64_t k, l;
int64_t m, n;
double d;
a.x = x;
k = a.i[0] & 0x7fffffffffffffffL;
if (k > 0x000fffff00000000L && k < 0x7ff0000000000000L)
{
if (x < 0)
return (big1 - big1) / (big - big);
l = (k & 0x001fffffffffffffL) | 0x3fe0000000000000L;
if ((a.i[1] & 0x7fffffffffffffffL) != 0)
{
n = (int64_t) ((l - k) * 2) >> 53;
m = (a.i[1] >> 52) & 0x7ff;
if (m == 0)
{
a.d[1] *= two54;
m = ((a.i[1] >> 52) & 0x7ff) - 54;
}
m += n;
if (m > 0)
a.i[1] = (a.i[1] & 0x800fffffffffffffL) | (m << 52);
else if (m <= -54)
{
a.i[1] &= 0x8000000000000000L;
}
else
{
m += 54;
a.i[1] = (a.i[1] & 0x800fffffffffffffL) | (m << 52);
a.d[1] *= twom54;
}
}
a.i[0] = l;
s = a.x;
d = bar (a.d[0]);
c.i[0] = 0x2000000000000000L + ((k & 0x7fe0000000000000L) >> 1);
c.i[1] = 0;
i = d;
t = 0.5L * (i + s / i);
i = 0.5L * (t + s / t);
return c.x * i;
}
else
{
if (k >= 0x7ff0000000000000L)
return x * x + x;
if (x == 0)
return x;
if (x < 0)
return (big1 - big1) / (big - big);
return tm256 * foo (x * t512);
}
}
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