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Optimize handling of denormals in logb/logbf/logbl

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This commit is contained in:
Andreas Schwab 2012-05-25 11:57:33 +02:00
parent d81dcb3569
commit 25dbcb277a
9 changed files with 46 additions and 32 deletions
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13
ChangeLog
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@ -1,3 +1,16 @@
2012-05-26 Andreas Schwab <schwab@linux-m68k.org>
* sysdeps/ieee754/dbl-64/s_logb.c (__logb): Optimize
handling of denormals.
* sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c (__logb): Likewise.
* sysdeps/ieee754/flt-32/s_logbf.c (__logbf): Likewise.
* sysdeps/ieee754/ldbl-96/s_logbl.c (__logbl): Likewise.
* sysdeps/ieee754/ldbl-128/s_logbl.c (__logbl): Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_logbl.c (__logbl): Likewise.
* sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c (_logb): Likewise.
* sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c (_logbl):
Likewise.
2012-05-25 Marek Polacek <polacek@redhat.com>
[BZ #14152]

10
sysdeps/ieee754/dbl-64/s_logb.c
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@ -34,10 +34,12 @@ __logb (double x)
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
int m1 = (ix == 0) ? 0 : __builtin_clz (ix);
int m2 = (lx == 0) ? 0 : __builtin_clz (lx);
int ma = (m1 == 0) ? m2 + 32 : m1;
return -1022.0 + (double)(11 - ma);
int ma;
if (ix == 0)
ma = __builtin_clz (lx) + 32;
else
ma = __builtin_clz (ix);
rix -= ma - 12;
}
return (double) (rix - 1023);
}

4
sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c
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@ -36,8 +36,8 @@ __logb (double x)
return x * x;
if (__builtin_expect (ex == 0, 0))
{
int m = (ix == 0) ? 0 : __builtin_clzll (ix);
return -1022.0 + (double)(11 -m);
int m = __builtin_clzll (ix);
ex -= m - 12;
}
return (double) (ex - 1023);
}

3
sysdeps/ieee754/flt-32/s_logbf.c
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@ -31,8 +31,7 @@ __logbf (float x)
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
int m = (ix == 0) ? 0 : __builtin_clz (ix);
return -126.0 + (float)(8 - m);
rix -= __builtin_clz (ix) - 9;
}
return (float) (rix - 127);
}

10
sysdeps/ieee754/ldbl-128/s_logbl.c
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@ -41,10 +41,12 @@ __logbl (long double x)
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
int m1 = (hx == 0) ? 0 : __builtin_clzll (hx);
int m2 = (lx == 0) ? 0 : __builtin_clzll (lx);
int ma = (m1 == 0) ? m2 + 64 : m1;
return -16382.0 + (long double)(15 - ma);
int ma;
if (hx == 0)
ma = __builtin_clzll (lx) + 64;
else
ma = __builtin_clzll (hx);
ex -= ma - 16;
}
return (long double) (ex - 16383);
}

7
sysdeps/ieee754/ldbl-128ibm/s_logbl.c
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@ -30,7 +30,7 @@ __logbl (long double x)
GET_LDOUBLE_WORDS64 (hx, lx, x);
hx &= 0x7fffffffffffffffLL; /* high |x| */
if ((hx | (lx & 0x7fffffffffffffffLL)) == 0)
if (hx == 0)
return -1.0 / fabs (x);
if (hx >= 0x7ff0000000000000LL)
return x * x;
@ -38,10 +38,7 @@ __logbl (long double x)
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
int m1 = (hx == 0) ? 0 : __builtin_clzll (hx);
int m2 = (lx == 0) ? 0 : __builtin_clzll (lx);
int ma = (m1 == 0) ? m2 + 64 : m1;
return -1022.0 + (long double)(11 - ma);
rhx -= __builtin_clzll (hx) - 12;
}
return (long double) (rhx - 1023);
}

10
sysdeps/ieee754/ldbl-96/s_logbl.c
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@ -38,10 +38,12 @@ __logbl (long double x)
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
int m1 = (ix == 0) ? 0 : __builtin_clz (ix);
int m2 = (lx == 0) ? 0 : __builtin_clz (lx);
int ma = (m1 == 0) ? m2 + 32 : m1;
return -16382.0 - (long double)(ma);
int ma;
if (ix == 0)
ma = __builtin_clz (lx) + 32;
else
ma = __builtin_clz (ix);
es -= ma - 1;
}
return (long double) (es - 16383);
}

13
sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c
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@ -55,13 +55,14 @@ __logb (double x)
/* POSIX specifies that denormal numbers are treated as
though they were normalized. */
int32_t lx, ix;
int m1, m2, ma;
int ma;
EXTRACT_WORDS (ix , lx, x);
m1 = (ix == 0) ? 0 : __builtin_clz (ix);
m2 = (lx == 0) ? 0 : __builtin_clz (lx);
ma = (m1 == 0) ? m2 + 32 : m1;
return -1022.0 + (double)(11 - ma);
EXTRACT_WORDS (ix, lx, x);
if (ix == 0)
ma = __builtin_clz (lx) + 32;
else
ma = __builtin_clz (ix);
return (double) (-1023 - (ma - 12));
}
/* Test to avoid logb_downward (0.0) == -0.0. */
return ret == -0.0 ? 0.0 : ret;

8
sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c
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@ -56,14 +56,12 @@ __logbl (long double x)
return (xh * xh);
else if (__builtin_expect (ret == two10m1, 0))
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
int64_t lx, hx;
int m1, m2, ma;
GET_LDOUBLE_WORDS64 (hx, lx, x);
m1 = (hx == 0) ? 0 : __builtin_clzll (hx);
m2 = (lx == 0) ? 0 : __builtin_clzll (lx);
ma = (m1 == 0) ? m2 + 64 : m1;
return -1022.0 + (double)(11 - ma);
return (long double) (-1023 - (__builtin_clzll (hx) - 12));
}
/* Test to avoid logb_downward (0.0) == -0.0. */
return ret == -0.0 ? 0.0 : ret;