GNU C Library master sources branch master updated. glibc-2.21-330-g0f4840b

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- Log -----------------------------------------------------------------
http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=0f4840be2528b3e3f2ecea009ab08e753701e9be

commit 0f4840be2528b3e3f2ecea009ab08e753701e9be
Author: OndÅ?ej Bílka <neleai@seznam.cz>
Date:   Tue Mar 18 11:01:38 2014 +0100

    Use strspn/strcspn/strpbrk ifunc in internal calls.
    
    To make a strtok faster and improve performance in general we need to do one
    additional change.
    
    A comment:
    
    /* It doesn't make sense to send libc-internal strcspn calls through a PLT.
       The speedup we get from using SSE4.2 instruction is likely eaten away
       by the indirect call in the PLT.  */
    
    Does not make sense at all because nobody bothered to check it. Gap
    between these implementations is quite big, when haystack is empty a
    sse2 is around 40 cycles slower because it needs to populate a lookup
    table and difference only increases with size. That is much bigger than
    plt slowdown which is few cycles.
    
    Even benchtest show a gap which also may be reverse by branch
    misprediction but my internal benchmark shown.
    
     simple_strspn stupid_strspn __strspn_sse42  __strspn_sse2
    Length    0, alignment  0, acc len  6:  18.6562 35.2344 17.0469 61.6719
    Length    6, alignment  0, acc len  6:  59.5469 72.5781 16.4219 73.625
    
    This patch also handles strpbrk which is implemented by including a
    x86_64/multiarch/strcspn.S file.
    
    	* sysdeps/x86_64/multiarch/strspn.S: Remove plt indirection.
    	* sysdeps/x86_64/multiarch/strcspn.S: Likewise.

diff --git a/ChangeLog b/ChangeLog
index 85234b3..f2f2447 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2015-05-12  OndÅ?ej Bílka  <neleai@seznam.cz>
+
+	* sysdeps/x86_64/multiarch/strcspn.S: Remove plt indirection.
+	* sysdeps/x86_64/multiarch/strspn.S: Likewise.
+
 2015-05-12  Roland McGrath  <roland@hack.frob.com>
 
 	* posix/uname-values.h: New file.
diff --git a/sysdeps/x86_64/multiarch/strcspn.S b/sysdeps/x86_64/multiarch/strcspn.S
index 00e4617..95e882c 100644
--- a/sysdeps/x86_64/multiarch/strcspn.S
+++ b/sysdeps/x86_64/multiarch/strcspn.S
@@ -65,14 +65,7 @@ END(STRCSPN)
 # undef END
 # define END(name) \
 	cfi_endproc; .size STRCSPN_SSE2, .-STRCSPN_SSE2
-# undef libc_hidden_builtin_def
-/* It doesn't make sense to send libc-internal strcspn calls through a PLT.
-   The speedup we get from using SSE4.2 instruction is likely eaten away
-   by the indirect call in the PLT.  */
-# define libc_hidden_builtin_def(name) \
-	.globl __GI_STRCSPN; __GI_STRCSPN = STRCSPN_SSE2
 #endif
-
 #endif /* HAVE_SSE4_SUPPORT */
 
 #ifdef USE_AS_STRPBRK
diff --git a/sysdeps/x86_64/multiarch/strspn.S b/sysdeps/x86_64/multiarch/strspn.S
index aea8e4c..b734c17 100644
--- a/sysdeps/x86_64/multiarch/strspn.S
+++ b/sysdeps/x86_64/multiarch/strspn.S
@@ -50,12 +50,6 @@ END(strspn)
 # undef END
 # define END(name) \
 	cfi_endproc; .size __strspn_sse2, .-__strspn_sse2
-# undef libc_hidden_builtin_def
-/* It doesn't make sense to send libc-internal strspn calls through a PLT.
-   The speedup we get from using SSE4.2 instruction is likely eaten away
-   by the indirect call in the PLT.  */
-# define libc_hidden_builtin_def(name) \
-	.globl __GI_strspn; __GI_strspn = __strspn_sse2
 #endif
 
 #endif /* HAVE_SSE4_SUPPORT */

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                          |    5 +++++
 sysdeps/x86_64/multiarch/strcspn.S |    7 -------
 sysdeps/x86_64/multiarch/strspn.S  |    6 ------
 3 files changed, 5 insertions(+), 13 deletions(-)


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