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c3d466cba1
glibc/sysdeps/m68k
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Wilco Dijkstra c3d466cba1 Remove slow paths from pow 
Remove the slow paths from pow.  Like several other double precision math
functions, pow is exactly rounded.  This is not required from math functions
and causes major overheads as it requires multiple fallbacks using higher
precision arithmetic if a result is close to 0.5ULP.  Ridiculous slowdowns
of up to 100000x have been reported when the highest precision path triggers.

All GLIBC math tests pass on AArch64 and x64 (with ULP of pow set to 1).
The worst case error is ~0.506ULP.  A simple test over a few hundred million
values shows pow is 10% faster on average.  This fixes BZ #13932.

	[BZ #13932]
	* sysdeps/ieee754/dbl-64/uexp.h (err_1): Remove.
	* benchtests/pow-inputs: Update comment for slow path cases.
	* manual/probes.texi (slowpow_p10): Delete removed probe.
	(slowpow_p10): Likewise.
	* math/Makefile: Remove halfulp.c and slowpow.c.
	* sysdeps/aarch64/libm-test-ulps: Set ULP of pow to 1.
	* sysdeps/generic/math_private.h (__exp1): Remove error argument.
	(__halfulp): Remove.
	(__slowpow): Remove.
	* sysdeps/i386/fpu/halfulp.c: Delete file.
	* sysdeps/i386/fpu/slowpow.c: Likewise.
	* sysdeps/ia64/fpu/halfulp.c: Likewise.
	* sysdeps/ia64/fpu/slowpow.c: Likewise.
	* sysdeps/ieee754/dbl-64/e_exp.c (__exp1): Remove error argument,
	improve comments and add error analysis.
	* sysdeps/ieee754/dbl-64/e_pow.c (__ieee754_pow): Add error analysis.
	(power1): Remove function:
	(log1): Remove error argument, add error analysis.
	(my_log2): Remove function.
	* sysdeps/ieee754/dbl-64/halfulp.c: Delete file.
	* sysdeps/ieee754/dbl-64/slowpow.c: Likewise.
	* sysdeps/m68k/m680x0/fpu/halfulp.c: Likewise.
	* sysdeps/m68k/m680x0/fpu/slowpow.c: Likewise.
	* sysdeps/powerpc/power4/fpu/Makefile: Remove CPPFLAGS-slowpow.c.
	* sysdeps/x86_64/fpu/libm-test-ulps: Set ULP of pow to 1.
	* sysdeps/x86_64/fpu/multiarch/Makefile: Remove slowpow-fma.c,
	slowpow-fma4.c, halfulp-fma.c, halfulp-fma4.c.
	* sysdeps/x86_64/fpu/multiarch/e_pow-fma.c (__slowpow): Remove define.
	* sysdeps/x86_64/fpu/multiarch/e_pow-fma4.c (__slowpow): Likewise.
	* sysdeps/x86_64/fpu/multiarch/halfulp-fma.c: Delete file.
	* sysdeps/x86_64/fpu/multiarch/halfulp-fma4.c: Likewise.
	* sysdeps/x86_64/fpu/multiarch/slowpow-fma.c: Likewise.
	* sysdeps/x86_64/fpu/multiarch/slowpow-fma4.c: Likewise.
2018-02-12 10:47:09 +00:00
..
bits Unify and simplify bits/byteswap.h, bits/byteswap-16.h headers (bug 14508, bug 15512, bug 17082, bug 20530). 2018-02-06 21:55:08 +00:00
coldfire Move LDBL_CLASSIFY_COMPAT to its own header. 2018-02-01 21:01:00 +00:00
fpu Fix m68k bits/fenv.h for no-FPU ColdFire. 2018-02-01 20:48:22 +00:00
m680x0 Remove slow paths from pow 2018-02-12 10:47:09 +00:00
nptl Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
sys Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
__longjmp.c Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
abort-instr.h
asm-syntax.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
backtrace.c Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
bsd-_setjmp.c Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
bsd-setjmp.c Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
crti.S Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
crtn.S Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
dl-machine.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
dl-tls.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
dl-trampoline.S Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
ffs.c Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
fpu_control.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
gccframe.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
Implies
jmpbuf-unwind.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
ldsodefs.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
libc-tls.c Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
Makefile Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
memchr.S Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
memcopy.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
memusage.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
preconfigure Remove --with-fp / --without-fp. 2017-12-12 13:56:47 +00:00
rawmemchr.S Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
setjmp.c Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
shlib-versions Remove configuration name patterns from shlib-versions. 2014-09-12 12:28:47 +00:00
sotruss-lib.c Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
stackinfo.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
start.S Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
strchr.S Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
strchrnul.S Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
symbol-hacks.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
sysdep.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
tls-macros.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
tst-audit.h Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
Versions
wcpcpy_chk.c Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00
wcpcpy.c Update copyright dates with scripts/update-copyrights. 2018-01-01 00:32:25 +00:00