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author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2019-03-18 17:40:50 +0000 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2019-07-08 17:21:15 -0300 |
commit | 69461d989669d3da051a2bfdae8d5b0ff3dc0749 (patch) | |
tree | ed4ae60dcce96b86f7ca77e556273b0f9c3814c8 /sysdeps/powerpc/fpu | |
parent | f215dbbdf18893b08e0b00eb12d369e7cf4a946d (diff) | |
download | glibc-69461d989669d3da051a2bfdae8d5b0ff3dc0749.zip glibc-69461d989669d3da051a2bfdae8d5b0ff3dc0749.tar.gz glibc-69461d989669d3da051a2bfdae8d5b0ff3dc0749.tar.bz2 |
powerpc: hypot refactor and optimization
The powerpc hypot is slight optimized by:
- Commit 8df4e219e43, both isnan and isinf are always inlined and thus
the check TEST_INF_NAN does not make sense anymore. The generic
check for POWER7 should be faster on all powerpc configuration.
- The redundant check 'y > two60factor && (x / y) > two60' is removed.
Both changes leads to unrequired ifunc especialization for power7 and
thus they are removed. Finally The code is also cleanup a bit by inlining
the constants floating points.
The performance changes using the hypot benchtests are:
- POWER9 without patch:
"hypot": {
"overflow": {
"duration": 4.98585e+09,
"iterations": 4.84932e+08,
"max": 46.551,
"min": 10.229,
"mean": 10.2815
},
"higher_two500": {
"duration": 5.00192e+09,
"iterations": 4.24843e+08,
"max": 33.319,
"min": 11.606,
"mean": 11.7736
},
"subnormal": {
"duration": 5.0075e+09,
"iterations": 4.06792e+08,
"max": 22.178,
"min": 12.15,
"mean": 12.3097
},
"less_two500": {
"duration": 5.00685e+09,
"iterations": 4.08772e+08,
"max": 22.784,
"min": 12.052,
"mean": 12.2485
},
"default": {
"duration": 5.06002e+09,
"iterations": 4.09894e+08,
"max": 20.648,
"min": 11.874,
"mean": 12.3447
}
}
- POWER9 with patch:
"hypot": {
"overflow": {
"duration": 4.91848e+09,
"iterations": 7.28039e+08,
"max": 47.958,
"min": 6.436,
"mean": 6.75579
},
"higher_two500": {
"duration": 4.9359e+09,
"iterations": 6.63376e+08,
"max": 20.783,
"min": 7.321,
"mean": 7.44057
},
"subnormal": {
"duration": 4.9479e+09,
"iterations": 6.19772e+08,
"max": 18.856,
"min": 7.817,
"mean": 7.98341
},
"less_two500": {
"duration": 4.94275e+09,
"iterations": 6.3889e+08,
"max": 17.452,
"min": 7.597,
"mean": 7.73647
},
"default": {
"duration": 5.03645e+09,
"iterations": 5.70718e+08,
"max": 18.904,
"min": 8.55,
"mean": 8.82476
}
}
- POWER7 without patch
"hypot": {
"overflow": {
"duration": 4.86637e+09,
"iterations": 6.43196e+08,
"max": 53.958,
"min": 7.328,
"mean": 7.56592
},
"higher_two500": {
"duration": 4.99842e+09,
"iterations": 3.11012e+08,
"max": 78.227,
"min": 15.696,
"mean": 16.0715
},
"subnormal": {
"duration": 4.99841e+09,
"iterations": 3.08935e+08,
"max": 51.392,
"min": 15.983,
"mean": 16.1795
},
"less_two500": {
"duration": 5.00108e+09,
"iterations": 2.99464e+08,
"max": 73.247,
"min": 16.416,
"mean": 16.7001
},
"default": {
"duration": 5.04645e+09,
"iterations": 3.52608e+08,
"max": 70.073,
"min": 13.38,
"mean": 14.3118
}
}
- POWER7 with patch
"hypot": {
"overflow": {
"duration": 4.80785e+09,
"iterations": 8.00001e+08,
"max": 66.262,
"min": 5.888,
"mean": 6.00981
},
"higher_two500": {
"duration": 4.9859e+09,
"iterations": 3.39449e+08,
"max": 5148.44,
"min": 14.539,
"mean": 14.6882
},
"subnormal": {
"duration": 4.9905e+09,
"iterations": 3.28874e+08,
"max": 64.905,
"min": 14.971,
"mean": 15.1745
},
"less_two500": {
"duration": 4.99494e+09,
"iterations": 3.19755e+08,
"max": 103.696,
"min": 14.972,
"mean": 15.6211
},
"default": {
"duration": 5.03951e+09,
"iterations": 4.02502e+08,
"max": 61.008,
"min": 12.368,
"mean": 12.5205
}
}
Checked on powerpc-linux-gnu (built without --with-cpu, with
--with-cpu=power4 and with --with-cpu=power5+ and --disable-multi-arch),
powerpc64-linux-gnu (built without --with-cp and with --with-cpu=power5+
and --disable-multi-arch).
* sysdeps/powerpc/fpu/e_hypot.c (two60, two500, two600, two1022,
twoM500, twoM600, two60factor, pdnum): Remove.
(TEST_INFO_NAN, GET_TW0_HIGH_WORD): Remove macro.
(__ieee754_hypot): Replace static variables with inline definition,
remove ununsed branches.
* sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
(libm-sysdep_routines): Remove e_hypot-* objects.
(CFLAGS-e_hypot-power7.c, CFLAGS-e_hypotf-power7.c): Remove rule.
* sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypot-power7.c: Remove
file.
* sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypot-ppc64.c: Likewise.
* sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypot.c: Likewise.
* sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypotf-power7.c: Likewise.
* sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypotf-ppc64.c: Likewise.
* sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypotf.c: Likewise.
Reviewed-by: Gabriel F. T. Gomes <gabrielftg@linux.ibm.com>
Diffstat (limited to 'sysdeps/powerpc/fpu')
-rw-r--r-- | sysdeps/powerpc/fpu/e_hypot.c | 94 |
1 files changed, 22 insertions, 72 deletions
diff --git a/sysdeps/powerpc/fpu/e_hypot.c b/sysdeps/powerpc/fpu/e_hypot.c index 039e5be..16cc55b 100644 --- a/sysdeps/powerpc/fpu/e_hypot.c +++ b/sysdeps/powerpc/fpu/e_hypot.c @@ -22,15 +22,6 @@ #include <math-underflow.h> #include <stdint.h> -static const double two60 = 1.152921504606847e+18; -static const double two500 = 3.2733906078961419e+150; -static const double two600 = 4.149515568880993e+180; -static const double two1022 = 4.49423283715579e+307; -static const double twoM500 = 3.054936363499605e-151; -static const double twoM600 = 2.4099198651028841e-181; -static const double two60factor = 1.5592502418239997e+290; -static const double pdnum = 2.225073858507201e-308; - /* __ieee754_hypot(x,y) * * This a FP only version without any FP->INT conversion. @@ -39,53 +30,18 @@ static const double pdnum = 2.225073858507201e-308; * is needed. */ -#ifdef _ARCH_PWR7 -/* POWER7 isinf and isnan optimization are fast. */ -# define TEST_INF_NAN(x, y) \ - if ((isinf(x) || isinf(y)) \ - && !issignaling (x) && !issignaling (y)) \ - return INFINITY; \ - if (isnan(x) || isnan(y)) \ - return x + y; -# else -/* For POWER6 and below isinf/isnan triggers LHS and PLT calls are - * costly (especially for POWER6). */ -# define GET_TW0_HIGH_WORD(d1,d2,i1,i2) \ - do { \ - ieee_double_shape_type gh_u1; \ - ieee_double_shape_type gh_u2; \ - gh_u1.value = (d1); \ - gh_u2.value = (d2); \ - (i1) = gh_u1.parts.msw & 0x7fffffff; \ - (i2) = gh_u2.parts.msw & 0x7fffffff; \ - } while (0) - -# define TEST_INF_NAN(x, y) \ - do { \ - uint32_t hx, hy; \ - GET_TW0_HIGH_WORD(x, y, hx, hy); \ - if (hy > hx) { \ - uint32_t ht = hx; hx = hy; hy = ht; \ - } \ - if (hx >= 0x7ff00000) { \ - if ((hx == 0x7ff00000 || hy == 0x7ff00000) \ - && !issignaling (x) && !issignaling (y)) \ - return INFINITY; \ - return x + y; \ - } \ - } while (0) - -#endif - - double __ieee754_hypot (double x, double y) { + if ((isinf (x) || isinf (y)) + && !issignaling (x) && !issignaling (y)) + return INFINITY; + if (isnan (x) || isnan (y)) + return x + y; + x = fabs (x); y = fabs (y); - TEST_INF_NAN (x, y); - if (y > x) { double t = x; @@ -94,40 +50,34 @@ __ieee754_hypot (double x, double y) } if (y == 0.0) return x; + /* if y is higher enough, y * 2^60 might overflow. The tests if y >= 1.7976931348623157e+308/2^60 (two60factor) and uses the appropriate check to avoid the overflow exception generation. */ - if (y > two60factor) - { - if ((x / y) > two60) - return x + y; - } - else - { - if (x > (y * two60)) - return x + y; - } - if (x > two500) + if (y <= 0x1.fffffffffffffp+963 && x > (y * 0x1p+60)) + return x + y; + + if (x > 0x1p+500) { - x *= twoM600; - y *= twoM600; - return sqrt (x * x + y * y) / twoM600; + x *= 0x1p-600; + y *= 0x1p-600; + return sqrt (x * x + y * y) / 0x1p-600; } - if (y < twoM500) + if (y < 0x1p-500) { - if (y <= pdnum) + if (y <= 0x0.fffffffffffffp-1022) { - x *= two1022; - y *= two1022; - double ret = sqrt (x * x + y * y) / two1022; + x *= 0x1p+1022; + y *= 0x1p+1022; + double ret = sqrt (x * x + y * y) / 0x1p+1022; math_check_force_underflow_nonneg (ret); return ret; } else { - x *= two600; - y *= two600; - return sqrt (x * x + y * y) / two600; + x *= 0x1p+600; + y *= 0x1p+600; + return sqrt (x * x + y * y) / 0x1p+600; } } return sqrt (x * x + y * y); |