From 25dbcb277a9dea5f241c0b888a30b9341310d941 Mon Sep 17 00:00:00 2001 From: Andreas Schwab Date: Fri, 25 May 2012 11:57:33 +0200 Subject: [PATCH] Optimize handling of denormals in logb/logbf/logbl --- ChangeLog | 13 +++++++++++++ sysdeps/ieee754/dbl-64/s_logb.c | 10 ++++++---- sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c | 4 ++-- sysdeps/ieee754/flt-32/s_logbf.c | 3 +-- sysdeps/ieee754/ldbl-128/s_logbl.c | 10 ++++++---- sysdeps/ieee754/ldbl-128ibm/s_logbl.c | 7 ++----- sysdeps/ieee754/ldbl-96/s_logbl.c | 10 ++++++---- sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c | 13 +++++++------ sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c | 8 +++----- 9 files changed, 46 insertions(+), 32 deletions(-) diff --git a/ChangeLog b/ChangeLog index a4ae965..6831676 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,16 @@ +2012-05-26 Andreas Schwab + + * 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 [BZ #14152] diff --git a/sysdeps/ieee754/dbl-64/s_logb.c b/sysdeps/ieee754/dbl-64/s_logb.c index baa35e1..17aa94b 100644 --- a/sysdeps/ieee754/dbl-64/s_logb.c +++ b/sysdeps/ieee754/dbl-64/s_logb.c @@ -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); } diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c index 185dd05..40b8888 100644 --- a/sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c +++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c @@ -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); } diff --git a/sysdeps/ieee754/flt-32/s_logbf.c b/sysdeps/ieee754/flt-32/s_logbf.c index 025c70d..e2b3aaa 100644 --- a/sysdeps/ieee754/flt-32/s_logbf.c +++ b/sysdeps/ieee754/flt-32/s_logbf.c @@ -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); } diff --git a/sysdeps/ieee754/ldbl-128/s_logbl.c b/sysdeps/ieee754/ldbl-128/s_logbl.c index cf6003e..3ba67b7 100644 --- a/sysdeps/ieee754/ldbl-128/s_logbl.c +++ b/sysdeps/ieee754/ldbl-128/s_logbl.c @@ -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); } diff --git a/sysdeps/ieee754/ldbl-128ibm/s_logbl.c b/sysdeps/ieee754/ldbl-128ibm/s_logbl.c index 678b6ca..92ce2c1 100644 --- a/sysdeps/ieee754/ldbl-128ibm/s_logbl.c +++ b/sysdeps/ieee754/ldbl-128ibm/s_logbl.c @@ -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); } diff --git a/sysdeps/ieee754/ldbl-96/s_logbl.c b/sysdeps/ieee754/ldbl-96/s_logbl.c index d8ad4bc..4289be1 100644 --- a/sysdeps/ieee754/ldbl-96/s_logbl.c +++ b/sysdeps/ieee754/ldbl-96/s_logbl.c @@ -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); } diff --git a/sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c b/sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c index fba4822..87176c3 100644 --- a/sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c +++ b/sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c @@ -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; diff --git a/sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c b/sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c index 03942ca..20c7d4e 100644 --- a/sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c +++ b/sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c @@ -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; -- 2.7.4