x86_64: Add support for __memcmpeq using sse2, avx2, and evex

No bug. This commit adds support for __memcmpeq to be implemented
seperately from memcmp. Support is added for versions optimized with
sse2, avx2, and evex.

12 files changed, 202 insertions, 9 deletions

diff --git a/sysdeps/generic/ifunc-init.h b/sysdeps/generic/ifunc-init.h
index 7f69485de8..ee8a8289c8 100644
--- a/sysdeps/generic/ifunc-init.h
+++ b/sysdeps/generic/ifunc-init.h
@@ -50,5 +50,8 @@
    '__<symbol>_<variant>' as the optimized implementation and
    '<symbol>_ifunc_selector' as the IFUNC selector.  */
 #define REDIRECT_NAME	EVALUATOR1 (__redirect, SYMBOL_NAME)
-#define OPTIMIZE(name)	EVALUATOR2 (SYMBOL_NAME, name)
 #define IFUNC_SELECTOR	EVALUATOR1 (SYMBOL_NAME, ifunc_selector)
+#define OPTIMIZE1(name)	EVALUATOR1 (SYMBOL_NAME, name)
+#define OPTIMIZE2(name)	EVALUATOR2 (SYMBOL_NAME, name)
+/* Default is to use OPTIMIZE2.  */
+#define OPTIMIZE(name)	OPTIMIZE2(name)
diff --git a/sysdeps/x86_64/memcmp.S b/sysdeps/x86_64/memcmp.S
index 8a03e572e8..b53f2c0866 100644
--- a/sysdeps/x86_64/memcmp.S
+++ b/sysdeps/x86_64/memcmp.S
@@ -356,9 +356,10 @@ L(ATR32res):
 	.p2align 4,, 4
 END(memcmp)
 
-#undef bcmp
+#ifdef USE_AS_MEMCMPEQ
+libc_hidden_def (memcmp)
+#else
+# undef bcmp
 weak_alias (memcmp, bcmp)
-#undef __memcmpeq
-strong_alias (memcmp, __memcmpeq)
 libc_hidden_builtin_def (memcmp)
-libc_hidden_def (__memcmpeq)
+#endif
diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
index 26be40959c..044778585b 100644
--- a/sysdeps/x86_64/multiarch/Makefile
+++ b/sysdeps/x86_64/multiarch/Makefile
@@ -7,7 +7,9 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c \
 		   memchr-sse2 rawmemchr-sse2 memchr-avx2 rawmemchr-avx2 \
 		   memrchr-sse2 memrchr-avx2 \
 		   memcmp-sse2 \
+		   memcmpeq-sse2 \
 		   memcmp-avx2-movbe \
+		   memcmpeq-avx2 \
 		   memcmp-sse4 memcpy-ssse3 \
 		   memmove-ssse3 \
 		   memcpy-ssse3-back \
@@ -42,6 +44,7 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c \
 		   memset-avx512-unaligned-erms \
 		   memchr-avx2-rtm \
 		   memcmp-avx2-movbe-rtm \
+		   memcmpeq-avx2-rtm \
 		   memmove-avx-unaligned-erms-rtm \
 		   memrchr-avx2-rtm \
 		   memset-avx2-unaligned-erms-rtm \
@@ -61,6 +64,7 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c \
 		   strrchr-avx2-rtm \
 		   memchr-evex \
 		   memcmp-evex-movbe \
+		   memcmpeq-evex \
 		   memmove-evex-unaligned-erms \
 		   memrchr-evex \
 		   memset-evex-unaligned-erms \
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index 39ab10613b..f7f3806d1d 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -38,6 +38,27 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   size_t i = 0;
 
+  /* Support sysdeps/x86_64/multiarch/memcmpeq.c.  */
+  IFUNC_IMPL (i, name, __memcmpeq,
+	      IFUNC_IMPL_ADD (array, i, __memcmpeq,
+			      (CPU_FEATURE_USABLE (AVX2)
+                   && CPU_FEATURE_USABLE (MOVBE)
+			       && CPU_FEATURE_USABLE (BMI2)),
+			      __memcmpeq_avx2)
+	      IFUNC_IMPL_ADD (array, i, __memcmpeq,
+			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)
+                   && CPU_FEATURE_USABLE (MOVBE)
+			       && CPU_FEATURE_USABLE (RTM)),
+			      __memcmpeq_avx2_rtm)
+	      IFUNC_IMPL_ADD (array, i, __memcmpeq,
+			      (CPU_FEATURE_USABLE (AVX512VL)
+			       && CPU_FEATURE_USABLE (AVX512BW)
+                   && CPU_FEATURE_USABLE (MOVBE)
+			       && CPU_FEATURE_USABLE (BMI2)),
+			      __memcmpeq_evex)
+	      IFUNC_IMPL_ADD (array, i, __memcmpeq, 1, __memcmpeq_sse2))
+
   /* Support sysdeps/x86_64/multiarch/memchr.c.  */
   IFUNC_IMPL (i, name, memchr,
 	      IFUNC_IMPL_ADD (array, i, memchr,
diff --git a/sysdeps/x86_64/multiarch/ifunc-memcmpeq.h b/sysdeps/x86_64/multiarch/ifunc-memcmpeq.h
new file mode 100644
index 0000000000..3319a9568a
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/ifunc-memcmpeq.h
@@ -0,0 +1,49 @@
+/* Common definition for __memcmpeq ifunc selections.
+   All versions must be listed in ifunc-impl-list.c.
+   Copyright (C) 2017-2021 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) OPTIMIZE1 (sse2) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx2) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx2_rtm) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE1 (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_FEATURE_USABLE_P (cpu_features, BMI2)
+      && CPU_FEATURE_USABLE_P (cpu_features, MOVBE)
+      && 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 OPTIMIZE1 (evex);
+
+      if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
+	return OPTIMIZE1 (avx2_rtm);
+
+      if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
+	return OPTIMIZE1 (avx2);
+    }
+
+  return OPTIMIZE1 (sse2);
+}
diff --git a/sysdeps/x86_64/multiarch/memcmp-sse2.S b/sysdeps/x86_64/multiarch/memcmp-sse2.S
index 7b30b7ca2e..132d6fb339 100644
--- a/sysdeps/x86_64/multiarch/memcmp-sse2.S
+++ b/sysdeps/x86_64/multiarch/memcmp-sse2.S
@@ -17,7 +17,9 @@
    <https://www.gnu.org/licenses/>.  */
 
 #if IS_IN (libc)
-# define memcmp __memcmp_sse2
+# ifndef memcmp
+#  define memcmp __memcmp_sse2
+# endif
 
 # ifdef SHARED
 #  undef libc_hidden_builtin_def
diff --git a/sysdeps/x86_64/multiarch/memcmp.c b/sysdeps/x86_64/multiarch/memcmp.c
index 7b3409b1dd..fe725f3563 100644
--- a/sysdeps/x86_64/multiarch/memcmp.c
+++ b/sysdeps/x86_64/multiarch/memcmp.c
@@ -29,9 +29,6 @@
 libc_ifunc_redirected (__redirect_memcmp, memcmp, IFUNC_SELECTOR ());
 # undef bcmp
 weak_alias (memcmp, bcmp)
-# undef __memcmpeq
-strong_alias (memcmp, __memcmpeq)
-libc_hidden_def (__memcmpeq)
 
 # ifdef SHARED
 __hidden_ver1 (memcmp, __GI_memcmp, __redirect_memcmp)
diff --git a/sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S b/sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S
new file mode 100644
index 0000000000..24b6a0c9ff
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S
@@ -0,0 +1,12 @@
+#ifndef MEMCMP
+# define MEMCMP __memcmpeq_avx2_rtm
+#endif
+
+#define ZERO_UPPER_VEC_REGISTERS_RETURN \
+  ZERO_UPPER_VEC_REGISTERS_RETURN_XTEST
+
+#define VZEROUPPER_RETURN jmp	 L(return_vzeroupper)
+
+#define SECTION(p) p##.avx.rtm
+
+#include "memcmpeq-avx2.S"
diff --git a/sysdeps/x86_64/multiarch/memcmpeq-avx2.S b/sysdeps/x86_64/multiarch/memcmpeq-avx2.S
new file mode 100644
index 0000000000..0181ea0d8d
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memcmpeq-avx2.S
@@ -0,0 +1,23 @@
+/* __memcmpeq optimized with AVX2.
+   Copyright (C) 2017-2021 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/>.  */
+
+#ifndef MEMCMP
+# define MEMCMP	__memcmpeq_avx2
+#endif
+
+#include "memcmp-avx2-movbe.S"
diff --git a/sysdeps/x86_64/multiarch/memcmpeq-evex.S b/sysdeps/x86_64/multiarch/memcmpeq-evex.S
new file mode 100644
index 0000000000..951e1e9560
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memcmpeq-evex.S
@@ -0,0 +1,23 @@
+/* __memcmpeq optimized with EVEX.
+   Copyright (C) 2017-2021 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/>.  */
+
+#ifndef MEMCMP
+# define MEMCMP	__memcmpeq_evex
+#endif
+
+#include "memcmp-evex-movbe.S"
diff --git a/sysdeps/x86_64/multiarch/memcmpeq-sse2.S b/sysdeps/x86_64/multiarch/memcmpeq-sse2.S
new file mode 100644
index 0000000000..c488cbbcd9
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memcmpeq-sse2.S
@@ -0,0 +1,23 @@
+/* __memcmpeq optimized with SSE2.
+   Copyright (C) 2017-2021 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/>.  */
+
+#ifndef memcmp
+# define memcmp	__memcmpeq_sse2
+#endif
+#define USE_AS_MEMCMPEQ	1
+#include "memcmp-sse2.S"
diff --git a/sysdeps/x86_64/multiarch/memcmpeq.c b/sysdeps/x86_64/multiarch/memcmpeq.c
new file mode 100644
index 0000000000..163e56047e
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memcmpeq.c
@@ -0,0 +1,35 @@
+/* Multiple versions of __memcmpeq.
+   All versions must be listed in ifunc-impl-list.c.
+   Copyright (C) 2017-2021 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 multiple versions only for the definition in libc.  */
+#if IS_IN (libc)
+# define __memcmpeq __redirect___memcmpeq
+# include <string.h>
+# undef __memcmpeq
+
+# define SYMBOL_NAME __memcmpeq
+# include "ifunc-memcmpeq.h"
+
+libc_ifunc_redirected (__redirect___memcmpeq, __memcmpeq, IFUNC_SELECTOR ());
+
+# ifdef SHARED
+__hidden_ver1 (__memcmpeq, __GI___memcmpeq, __redirect___memcmpeq)
+    __attribute__ ((visibility ("hidden"))) __attribute_copy__ (__memcmpeq);
+# endif
+#endif