[glibc] x86: Remove generic strncat, strncpy, and stpncpy implementations

[Noah Goldstein <nwg@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9c38deec96ebe1b052a0c1bef137b90967755f18

commit 9c38deec96ebe1b052a0c1bef137b90967755f18
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Tue Jul 5 17:06:41 2022 -0700

    x86: Remove generic strncat, strncpy, and stpncpy implementations
    
    These functions all have optimized versions:
    __strncat_sse2_unaligned, __strncpy_sse2_unaligned, and
    stpncpy_sse2_unaligned which are faster than their respective generic
    implementations.  Since the sse2 versions can run on baseline x86_64,
    we should use these as the baseline implementation and can remove the
    generic implementations.
    
    Geometric mean of N=20 runs of the entire benchmark suite on:
    11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz (Tigerlake)
    
    __strncat_sse2_unaligned / __strncat_generic: .944
    __strncpy_sse2_unaligned / __strncpy_generic: .726
    __stpncpy_sse2_unaligned / __stpncpy_generic: .650
    
    Tested build with and without multiarch and full check with multiarch.

Diff:
---
 sysdeps/x86_64/multiarch/Makefile          |  3 --
 sysdeps/x86_64/multiarch/ifunc-impl-list.c |  9 ++----
 sysdeps/x86_64/multiarch/ifunc-strcpy.h    |  8 ++---
 sysdeps/x86_64/multiarch/ifunc-strncpy.h   | 48 ++++++++++++++++++++++++++++++
 sysdeps/x86_64/multiarch/stpncpy-generic.c | 26 ----------------
 sysdeps/x86_64/multiarch/stpncpy.c         |  3 +-
 sysdeps/x86_64/multiarch/strncat-generic.c | 21 -------------
 sysdeps/x86_64/multiarch/strncat.c         |  3 +-
 sysdeps/x86_64/multiarch/strncpy-generic.c | 24 ---------------
 sysdeps/x86_64/multiarch/strncpy.c         |  3 +-
 10 files changed, 56 insertions(+), 92 deletions(-)

diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
index 7ba9ad5139..d6b62af850 100644
--- a/sysdeps/x86_64/multiarch/Makefile
+++ b/sysdeps/x86_64/multiarch/Makefile
@@ -45,7 +45,6 @@ sysdep_routines += \
   stpcpy-sse2-unaligned \
   stpncpy-avx2 \
   stpncpy-avx2-rtm \
-  stpncpy-generic \
   stpncpy-evex \
   stpncpy-sse2-unaligned \
   strcasecmp_l-avx2 \
@@ -91,7 +90,6 @@ sysdep_routines += \
   strncase_l-sse4_2 \
   strncat-avx2 \
   strncat-avx2-rtm \
-  strncat-generic \
   strncat-evex \
   strncat-sse2-unaligned \
   strncmp-avx2 \
@@ -101,7 +99,6 @@ sysdep_routines += \
   strncmp-sse4_2 \
   strncpy-avx2 \
   strncpy-avx2-rtm \
-  strncpy-generic \
   strncpy-evex \
   strncpy-sse2-unaligned \
   strnlen-avx2 \
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index adf7d4bafd..2c96cb62d2 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -403,8 +403,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 			       && CPU_FEATURE_USABLE (AVX512BW)),
 			      __stpncpy_evex)
 	      IFUNC_IMPL_ADD (array, i, stpncpy, 1,
-			      __stpncpy_sse2_unaligned)
-	      IFUNC_IMPL_ADD (array, i, stpncpy, 1, __stpncpy_generic))
+			      __stpncpy_sse2_unaligned))
 
   /* Support sysdeps/x86_64/multiarch/stpcpy.c.  */
   IFUNC_IMPL (i, name, stpcpy,
@@ -618,8 +617,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 			       && CPU_FEATURE_USABLE (AVX512BW)),
 			      __strncat_evex)
 	      IFUNC_IMPL_ADD (array, i, strncat, 1,
-			      __strncat_sse2_unaligned)
-	      IFUNC_IMPL_ADD (array, i, strncat, 1, __strncat_generic))
+			      __strncat_sse2_unaligned))
 
   /* Support sysdeps/x86_64/multiarch/strncpy.c.  */
   IFUNC_IMPL (i, name, strncpy,
@@ -634,8 +632,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 			       && CPU_FEATURE_USABLE (AVX512BW)),
 			      __strncpy_evex)
 	      IFUNC_IMPL_ADD (array, i, strncpy, 1,
-			      __strncpy_sse2_unaligned)
-	      IFUNC_IMPL_ADD (array, i, strncpy, 1, __strncpy_generic))
+			      __strncpy_sse2_unaligned))
 
   /* Support sysdeps/x86_64/multiarch/strpbrk.c.  */
   IFUNC_IMPL (i, name, strpbrk,
diff --git a/sysdeps/x86_64/multiarch/ifunc-strcpy.h b/sysdeps/x86_64/multiarch/ifunc-strcpy.h
index 80529458d1..a15afa44e9 100644
--- a/sysdeps/x86_64/multiarch/ifunc-strcpy.h
+++ b/sysdeps/x86_64/multiarch/ifunc-strcpy.h
@@ -20,11 +20,7 @@
 
 #include <init-arch.h>
 
-#ifndef GENERIC
-# define GENERIC sse2
-#endif
-
-extern __typeof (REDIRECT_NAME) OPTIMIZE (GENERIC) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
 extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2_unaligned)
   attribute_hidden;
 extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
@@ -53,5 +49,5 @@ IFUNC_SELECTOR (void)
   if (CPU_FEATURES_ARCH_P (cpu_features, Fast_Unaligned_Load))
     return OPTIMIZE (sse2_unaligned);
 
-  return OPTIMIZE (GENERIC);
+  return OPTIMIZE (sse2);
 }
diff --git a/sysdeps/x86_64/multiarch/ifunc-strncpy.h b/sysdeps/x86_64/multiarch/ifunc-strncpy.h
new file mode 100644
index 0000000000..323225af4d
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/ifunc-strncpy.h
@@ -0,0 +1,48 @@
+/* Common definition for ifunc st{r|p}n{cpy|cat}
+   All versions must be listed in ifunc-impl-list.c.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <init-arch.h>
+
+extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2_unaligned)
+  attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_rtm) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE (evex) attribute_hidden;
+
+static inline void *
+IFUNC_SELECTOR (void)
+{
+  const struct cpu_features* cpu_features = __get_cpu_features ();
+
+  if (CPU_FEATURE_USABLE_P (cpu_features, AVX2)
+      && CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
+    {
+      if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
+	  && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
+	return OPTIMIZE (evex);
+
+      if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
+	return OPTIMIZE (avx2_rtm);
+
+      if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
+	return OPTIMIZE (avx2);
+    }
+
+  return OPTIMIZE (sse2_unaligned);
+}
diff --git a/sysdeps/x86_64/multiarch/stpncpy-generic.c b/sysdeps/x86_64/multiarch/stpncpy-generic.c
deleted file mode 100644
index 87826845b0..0000000000
--- a/sysdeps/x86_64/multiarch/stpncpy-generic.c
+++ /dev/null
@@ -1,26 +0,0 @@
-/* stpncpy.
-   Copyright (C) 2022 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-
-#define STPNCPY __stpncpy_generic
-#undef weak_alias
-#define weak_alias(ignored1, ignored2)
-#undef libc_hidden_def
-#define libc_hidden_def(stpncpy)
-
-#include <string/stpncpy.c>
diff --git a/sysdeps/x86_64/multiarch/stpncpy.c b/sysdeps/x86_64/multiarch/stpncpy.c
index 879bc83f0b..a8d083ff0d 100644
--- a/sysdeps/x86_64/multiarch/stpncpy.c
+++ b/sysdeps/x86_64/multiarch/stpncpy.c
@@ -25,9 +25,8 @@
 # undef stpncpy
 # undef __stpncpy
 
-# define GENERIC generic
 # define SYMBOL_NAME stpncpy
-# include "ifunc-strcpy.h"
+# include "ifunc-strncpy.h"
 
 libc_ifunc_redirected (__redirect_stpncpy, __stpncpy, IFUNC_SELECTOR ());
 
diff --git a/sysdeps/x86_64/multiarch/strncat-generic.c b/sysdeps/x86_64/multiarch/strncat-generic.c
deleted file mode 100644
index 0090669cd1..0000000000
--- a/sysdeps/x86_64/multiarch/strncat-generic.c
+++ /dev/null
@@ -1,21 +0,0 @@
-/* strncat.
-   Copyright (C) 2022 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-
-#define STRNCAT __strncat_generic
-#include <string/strncat.c>
diff --git a/sysdeps/x86_64/multiarch/strncat.c b/sysdeps/x86_64/multiarch/strncat.c
index 50fba8a41f..a590c25d51 100644
--- a/sysdeps/x86_64/multiarch/strncat.c
+++ b/sysdeps/x86_64/multiarch/strncat.c
@@ -24,8 +24,7 @@
 # undef strncat
 
 # define SYMBOL_NAME strncat
-# define GENERIC generic
-# include "ifunc-strcpy.h"
+# include "ifunc-strncpy.h"
 
 libc_ifunc_redirected (__redirect_strncat, strncat, IFUNC_SELECTOR ());
 strong_alias (strncat, __strncat);
diff --git a/sysdeps/x86_64/multiarch/strncpy-generic.c b/sysdeps/x86_64/multiarch/strncpy-generic.c
deleted file mode 100644
index 9916153dd5..0000000000
--- a/sysdeps/x86_64/multiarch/strncpy-generic.c
+++ /dev/null
@@ -1,24 +0,0 @@
-/* strncpy.
-   Copyright (C) 2022 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-
-#define STRNCPY __strncpy_generic
-#undef libc_hidden_builtin_def
-#define libc_hidden_builtin_def(strncpy)
-
-#include <string/strncpy.c>
diff --git a/sysdeps/x86_64/multiarch/strncpy.c b/sysdeps/x86_64/multiarch/strncpy.c
index 7fc7d72ec5..c83440f0e3 100644
--- a/sysdeps/x86_64/multiarch/strncpy.c
+++ b/sysdeps/x86_64/multiarch/strncpy.c
@@ -24,8 +24,7 @@
 # undef strncpy
 
 # define SYMBOL_NAME strncpy
-# define GENERIC generic
-# include "ifunc-strcpy.h"
+# include "ifunc-strncpy.h"
 
 libc_ifunc_redirected (__redirect_strncpy, strncpy, IFUNC_SELECTOR ());