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Re: [PATCH] x86-64: Update strlen.S to support wcslen/wcsnlen
- From: Markus Trippelsdorf <markus at trippelsdorf dot de>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Tue, 6 Jun 2017 07:37:10 +0200
- Subject: Re: [PATCH] x86-64: Update strlen.S to support wcslen/wcsnlen
- Authentication-results: sourceware.org; auth=none
- References: <20170520135619.GA17481@gmail.com> <CAMe9rOrik_jJkM+vd9n7LuPEUR=xM7T8MC1cMiFXgnPsYUiTEw@mail.gmail.com> <CAMe9rOroGR3vbxw_uRkNzhy25iwUocqneuj0zd2DFtAcw7Vy9w@mail.gmail.com>
On 2017.06.05 at 07:24 -0700, H.J. Lu wrote:
> On Tue, May 30, 2017 at 3:14 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> > On Sat, May 20, 2017 at 6:56 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> >> The difference between strlen and wcslen is byte vs int. We can
> >> replace pminub and pcmpeqb with pminud and pcmpeqd to turn strlen
> >> into wcslen. Tested on Ivy Bridge with benchtests/bench-wcslen.c,
> >> the new strlen based wcslen is as fast as the old wcslen.
> >>
> >> OK for master?
> >>
> >> H.J.
> >> ---
> >> * sysdeps/x86_64/strlen.S (PMINU): New.
> >> (PCMPEQ): Likewise.
> >> (SHIFT_RETURN): Likewise.
> >> (FIND_ZERO): Replace pcmpeqb with PCMPEQ.
> >> (strlen): Add SHIFT_RETURN before ret. Replace pcmpeqb and
> >> pminub with PCMPEQ and PMINU.
> >> * sysdeps/x86_64/wcslen.S: Define AS_WCSLEN and strlen.
> >> Include "strlen.S".
> >> * sysdeps/x86_64/wcsnlen.S: New file.
> >
> > Here is the updated patch only with SSE2 wcsnlen.S. Any
> > comments?
> >
>
> I will check it in today.
It doesn't work on old machines without SSE4.1:
FAIL: stdio-common/tstdiomisc
FAIL: wcsmbs/test-wcpncpy
FAIL: wcsmbs/test-wcsncmp
FAIL: wcsmbs/test-wcsncpy
FAIL: wcsmbs/test-wcsnlen
FAIL: wcsmbs/wcsatcliff
markus@x4 tmp % gdb --args /var/tmp/glibc-build/elf/ld-linux-x86-64.so.2 --library-path /var/tmp/glibc-build:/var/tmp/glibc-build/math:/var/tmp/glibc-build/elf:/var/tmp/gl[31/150]d/dlfcn:/var/tmp/glibc-build/nss:/var/tmp/glibc-build/nis:/var/tmp/glibc-build/rt:/var/tmp/glibc-build/resolv:/var/tmp/glibc-build/crypt:/var/tmp/glibc-build/mathvec:/var/tmp/glib
c-build/support:/var/tmp/glibc-build/nptl /var/tmp/glibc-build/stdio-common/tstdiomisc
Reading symbols from /var/tmp/glibc-build/elf/ld-linux-x86-64.so.2...done.
(gdb) run
Starting program: /home/markus/tmp/glibc-build/elf/ld-linux-x86-64.so.2 --library-path /var/tmp/glibc-build:/var/tmp/glibc-build/math:/var/tmp/glibc-build/elf:/var/tmp/glibc-build/dlfcn:/var/tmp/glibc-build/nss:/var/tmp/glibc-build/nis:/var/tmp/glibc-build/rt:/var/tmp/glibc-build/resolv:/var/tmp/glibc-build/crypt:/var/tmp/glibc-build/mathvec:/var/tmp/glibc-build/support:/var/tmp/glibc-build/nptl /var/tmp/glibc-build/stdio-common/tstdiomisc
t1: count=5
sscanf ("12345", "%ld", &x) => 1, x = 12345
sscanf ("12345", "%llllld", &x) => 0, x = -1
sscanf ("12345", "%LLLLLd", &x) => 0, x = -1
sscanf ("test ", "%*s%n", &x) => 0, x = 4
sscanf ("test ", "%2*s%n", &x) => 0, x = -1
sscanf ("12 ", "%l2d", &x) => 0, x = -1
sscanf ("12 ", "%2ld", &x) => 1, x = 12
sscanf ("1 1", "%d %Z", &n, &N) => 1, n = 1, N = -1
expected "nan NAN nan NAN nan NAN nan NAN", got "nan NAN nan NAN nan NAN nan NAN"
expected "-nan -NAN -nan -NAN -nan -NAN -nan -NAN", got "-nan -NAN -nan -NAN -nan -NAN -nan -NAN"
expected "nan NAN nan NAN nan NAN nan NAN", got "nan NAN nan NAN nan NAN nan NAN"
expected "-nan -NAN -nan -NAN -nan -NAN -nan -NAN", got "-nan -NAN -nan -NAN -nan -NAN -nan -NAN" expected "inf INF inf INF inf INF inf INF", got "inf INF inf INF inf INF inf INF"
expected "-inf -INF -inf -INF -inf -INF -inf -INF", got "-inf -INF -inf -INF -inf -INF -inf -INF"
Program received signal SIGILL, Illegal instruction.
wcsnlen () at ../sysdeps/x86_64/strlen.S:180
180 PMINU 16(%rax), %xmm0
--
Markus