powerpc64: strchr/strchrnul optimization for power8

The P7 code is used for <=32B strings and for > 32B vectorized loops are used.
This shows as an average 25% improvement depending on the position of search
character.  The performance is same for shorter strings.
Tested on ppc64 and ppc64le.

8 files changed, 483 insertions, 2 deletions

diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index 2997b9d6fb..f5889a322b 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -10,8 +10,8 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
 		   strncase-power7 strncase_l-power7 \
 		   strncmp-power9 strncmp-power8 strncmp-power7 \
 		   strncmp-power4 strncmp-ppc64 \
-		   strchr-power7 strchr-ppc64 \
-		   strchrnul-power7 strchrnul-ppc64 \
+		   strchr-power8 strchr-power7 strchr-ppc64 \
+		   strchrnul-power8 strchrnul-power7 strchrnul-ppc64 \
 		   strcpy-power8 strcpy-power7 strcpy-ppc64 stpcpy-power8 \
 		   stpcpy-power7 stpcpy-ppc64 \
 		   strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
index 2d085a206b..703a49b421 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -124,6 +124,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/powerpc/powerpc64/multiarch/strchr.c.  */
   IFUNC_IMPL (i, name, strchr,
 	      IFUNC_IMPL_ADD (array, i, strchr,
+			      hwcap2 & PPC_FEATURE2_ARCH_2_07,
+			      __strchr_power8)
+	      IFUNC_IMPL_ADD (array, i, strchr,
 			      hwcap & PPC_FEATURE_HAS_VSX,
 			      __strchr_power7)
 	      IFUNC_IMPL_ADD (array, i, strchr, 1,
@@ -132,6 +135,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/powerpc/powerpc64/multiarch/strchrnul.c.  */
   IFUNC_IMPL (i, name, strchrnul,
 	      IFUNC_IMPL_ADD (array, i, strchrnul,
+			      hwcap2 & PPC_FEATURE2_ARCH_2_07,
+			      __strchrnul_power8)
+	      IFUNC_IMPL_ADD (array, i, strchrnul,
 			      hwcap & PPC_FEATURE_HAS_VSX,
 			      __strchrnul_power7)
 	      IFUNC_IMPL_ADD (array, i, strchrnul, 1,
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strchr-power8.S b/sysdeps/powerpc/powerpc64/multiarch/strchr-power8.S
new file mode 100644
index 0000000000..dd0b7f5b28
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strchr-power8.S
@@ -0,0 +1,39 @@
+/* Optimized strchr implementation for POWER8.
+   Copyright (C) 2016 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+#undef ENTRY
+#define ENTRY(name)						\
+  .section ".text";						\
+  ENTRY_2(__strchr_power8)					\
+  .align ALIGNARG(2);						\
+  BODY_LABEL(__strchr_power8):					\
+  cfi_startproc;						\
+  LOCALENTRY(__strchr_power8)
+
+#undef END
+#define END(name)						\
+  cfi_endproc;							\
+  TRACEBACK(__strchr_power8)					\
+  END_2(__strchr_power8)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#include <sysdeps/powerpc/powerpc64/power8/strchr.S>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strchr.c b/sysdeps/powerpc/powerpc64/multiarch/strchr.c
index e24d6b319e..2ffb1f6c5d 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/strchr.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/strchr.c
@@ -27,11 +27,14 @@
 
 extern __typeof (strchr) __strchr_ppc attribute_hidden;
 extern __typeof (strchr) __strchr_power7 attribute_hidden;
+extern __typeof (strchr) __strchr_power8 attribute_hidden;
 # undef strchr
 
 /* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
    ifunc symbol properly.  */
 libc_ifunc_redirected (__redirect_strchr, strchr,
+		       (hwcap2 & PPC_FEATURE2_ARCH_2_07)
+		       ? __strchr_power8 :
 		       (hwcap & PPC_FEATURE_HAS_VSX)
 		       ? __strchr_power7
 		       : __strchr_ppc);
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strchrnul-power8.S b/sysdeps/powerpc/powerpc64/multiarch/strchrnul-power8.S
new file mode 100644
index 0000000000..d0bfedac22
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strchrnul-power8.S
@@ -0,0 +1,39 @@
+/* Optimized strchrnul implementation for POWER8.
+   Copyright (C) 2016 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+#undef ENTRY
+#define ENTRY(name)						\
+  .section ".text";						\
+  ENTRY_2(__strchrnul_power8)					\
+  .align ALIGNARG(2);						\
+  BODY_LABEL(__strchrnul_power8):				\
+  cfi_startproc;						\
+  LOCALENTRY(__strchrnul_power8)
+
+#undef END
+#define END(name)						\
+  cfi_endproc;							\
+  TRACEBACK(__strchrnul_power8)					\
+  END_2(__strchrnul_power8)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#include <sysdeps/powerpc/powerpc64/power8/strchrnul.S>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strchrnul.c b/sysdeps/powerpc/powerpc64/multiarch/strchrnul.c
index 682aa0fef7..63df401d51 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/strchrnul.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/strchrnul.c
@@ -23,10 +23,13 @@
 
 extern __typeof (__strchrnul) __strchrnul_ppc attribute_hidden;
 extern __typeof (__strchrnul) __strchrnul_power7 attribute_hidden;
+extern __typeof (__strchrnul) __strchrnul_power8 attribute_hidden;
 
 /* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
    ifunc symbol properly.  */
 libc_ifunc (__strchrnul,
+	    (hwcap2 & PPC_FEATURE2_ARCH_2_07)
+	    ? __strchrnul_power8 :
 	    (hwcap & PPC_FEATURE_HAS_VSX)
             ? __strchrnul_power7
             : __strchrnul_ppc);
diff --git a/sysdeps/powerpc/powerpc64/power8/strchr.S b/sysdeps/powerpc/powerpc64/power8/strchr.S
new file mode 100644
index 0000000000..331d0a6c48
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/power8/strchr.S
@@ -0,0 +1,368 @@
+/* Optimized strchr implementation for PowerPC64/POWER8.
+   Copyright (C) 2016 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+#ifdef USE_AS_STRCHRNUL
+# define FUNC_NAME __strchrnul
+#else
+# define FUNC_NAME strchr
+#endif
+/* int [r3] strchr (char *s [r3], int c [r4])  */
+/* TODO: change these to the actual instructions when the minimum required
+   binutils allows it.  */
+#define MTVRD(v,r) .long (0x7c000167 | ((v)<<(32-11)) | ((r)<<(32-16)))
+#define MFVRD(r,v) .long (0x7c000067 | ((v)<<(32-11)) | ((r)<<(32-16)))
+#define VBPERMQ(t,a,b)  .long (0x1000054c \
+			| ((t)<<(32-11)) \
+			| ((a)<<(32-16)) \
+			| ((b)<<(32-21)) )
+/* TODO: change this to .machine power8 when the minimum required binutils
+   allows it.  */
+	.machine  power7
+ENTRY (FUNC_NAME)
+	CALL_MCOUNT 2
+	dcbt	0,r3
+	clrrdi	r8,r3,3	      /* Align the address to doubleword boundary.  */
+	cmpdi	cr7,r4,0
+	ld	r12,0(r8)     /* Load doubleword from memory.  */
+	li	r0,0	      /* Doubleword with null chars to use
+				 with cmpb.  */
+
+	rlwinm	r6,r3,3,26,28 /* Calculate padding.  */
+
+	beq	cr7,L(null_match)
+
+	/* Replicate byte to doubleword.  */
+	insrdi	r4,r4,8,48
+	insrdi	r4,r4,16,32
+	insrdi  r4,r4,32,0
+
+	/* Now r4 has a doubleword of c bytes and r0 has
+	   a doubleword of null bytes.  */
+
+	cmpb	r10,r12,r4     /* Compare each byte against c byte.  */
+	cmpb	r11,r12,r0     /* Compare each byte against null byte.  */
+
+	/* Move the doublewords left and right to discard the bits that are
+	   not part of the string and bring them back as zeros.  */
+#ifdef __LITTLE_ENDIAN__
+	srd	r10,r10,r6
+	srd	r11,r11,r6
+	sld	r10,r10,r6
+	sld	r11,r11,r6
+#else
+	sld	r10,r10,r6
+	sld	r11,r11,r6
+	srd	r10,r10,r6
+	srd	r11,r11,r6
+#endif
+	or	r5,r10,r11    /* OR the results to speed things up.  */
+	cmpdi	cr7,r5,0      /* If r5 == 0, no c or null bytes
+				 have been found.  */
+	bne	cr7,L(done)
+
+	mtcrf   0x01,r8
+
+	/* Are we now aligned to a doubleword boundary?  If so, skip to
+	   the main loop.  Otherwise, go through the alignment code.  */
+
+	bt	28,L(loop)
+
+	/* Handle WORD2 of pair.  */
+	ldu	r12,8(r8)
+	cmpb    r10,r12,r4
+	cmpb	r11,r12,r0
+	or	r5,r10,r11
+	cmpdi	cr7,r5,0
+	bne	cr7,L(done)
+	b	L(loop)	      /* We branch here (rather than falling through)
+				 to skip the nops due to heavy alignment
+				 of the loop below.  */
+
+	.p2align  5
+L(loop):
+	/* Load two doublewords, compare and merge in a
+	   single register for speed.  This is an attempt
+	   to speed up the null-checking process for bigger strings.  */
+	ld	r12,8(r8)
+	ldu	r9,16(r8)
+	cmpb	r10,r12,r4
+	cmpb	r11,r12,r0
+	cmpb	r6,r9,r4
+	cmpb	r7,r9,r0
+	or	r5,r10,r11
+	or	r9,r6,r7
+	or	r12,r5,r9
+	cmpdi	cr7,r12,0
+	beq	cr7,L(vector)
+	/* OK, one (or both) of the doublewords contains a c/null byte.  Check
+	   the first doubleword and decrement the address in case the first
+	   doubleword really contains a c/null byte.  */
+
+	cmpdi	cr6,r5,0
+	addi	r8,r8,-8
+	bne	cr6,L(done)
+
+	/* The c/null byte must be in the second doubleword.  Adjust the
+	   address again and move the result of cmpb to r10 so we can calculate
+	   the pointer.  */
+
+	mr	r10,r6
+	mr	r11,r7
+	addi	r8,r8,8
+#ifdef USE_AS_STRCHRNUL
+	mr	r5, r9
+#endif
+	/* r10/r11 have the output of the cmpb instructions, that is,
+	   0xff in the same position as the c/null byte in the original
+	   doubleword from the string.  Use that to calculate the pointer.  */
+L(done):
+#ifdef USE_AS_STRCHRNUL
+	mr	r10, r5
+#endif
+#ifdef __LITTLE_ENDIAN__
+	addi    r3,r10,-1
+	andc    r3,r3,r10
+	popcntd	r0,r3
+# ifndef USE_AS_STRCHRNUL
+	addi    r4,r11,-1
+	andc    r4,r4,r11
+	cmpld	cr7,r3,r4
+	bgt	cr7,L(no_match)
+# endif
+#else
+	cntlzd	r0,r10	      /* Count leading zeros before c matches.  */
+# ifndef USE_AS_STRCHRNUL
+	cmpld	cr7,r11,r10
+	bgt	cr7,L(no_match)
+# endif
+#endif
+	srdi	r0,r0,3	      /* Convert leading zeros to bytes.  */
+	add	r3,r8,r0      /* Return address of the matching c byte
+				 or null in case c was not found.  */
+	blr
+
+	/* Check the first 32B in GPR's and move to vectorized loop.  */
+	.p2align  5
+L(vector):
+	addi	r3, r8, 8
+	andi.	r10, r3, 31
+	bne	cr0, L(loop)
+	vspltisb	v0, 0
+	/* Precompute vbpermq constant.  */
+	vspltisb	v10, 3
+	lvsl	v11, r0, r0
+	vslb	v10, v11, v10
+	MTVRD(v1,r4)
+	li	r5, 16
+	vspltb	v1, v1, 7
+	/* Compare 32 bytes in each loop.  */
+L(continue):
+	lvx	v4, 0, r3
+	lvx	v5, r3, r5
+	vcmpequb	v2, v0, v4
+	vcmpequb	v3, v0, v5
+	vcmpequb	v6, v1, v4
+	vcmpequb	v7, v1, v5
+	vor	v8, v2, v3
+	vor	v9, v6, v7
+	vor	v11, v8, v9
+	vcmpequb.	v11, v0, v11
+	addi	r3, r3, 32
+	blt	cr6, L(continue)
+	/* One (or both) of the quadwords contains a c/null byte.  */
+	addi	r3, r3, -32
+#ifndef USE_AS_STRCHRNUL
+	vcmpequb.	v11, v0, v9
+	blt	cr6, L(no_match)
+#endif
+	/* Permute the first bit of each byte into bits 48-63.  */
+	VBPERMQ(v2, v2, v10)
+	VBPERMQ(v3, v3, v10)
+	VBPERMQ(v6, v6, v10)
+	VBPERMQ(v7, v7, v10)
+	/* Shift each component into its correct position for merging.  */
+#ifdef __LITTLE_ENDIAN__
+	vsldoi	v3, v3, v3, 2
+	vsldoi	v7, v7, v7, 2
+#else
+	vsldoi	v2, v2, v2, 6
+	vsldoi	v3, v3, v3, 4
+	vsldoi	v6, v6, v6, 6
+	vsldoi	v7, v7, v7, 4
+#endif
+
+        /* Merge the results and move to a GPR.  */
+        vor     v1, v3, v2
+        vor     v2, v6, v7
+        vor     v4, v1, v2
+	MFVRD(r5, v4)
+#ifdef __LITTLE_ENDIAN__
+	addi	r6, r5, -1
+	andc	r6, r6, r5
+	popcntd	r6, r6
+#else
+	cntlzd	r6, r5	/* Count leading zeros before the match.  */
+#endif
+	add	r3, r3, r6	/* Compute final length.  */
+	/* Return NULL if null found before c.  */
+#ifndef USE_AS_STRCHRNUL
+	lbz	r4, 0(r3)
+	cmpdi	cr7, r4, 0
+	beq	cr7, L(no_match)
+#endif
+	blr
+
+#ifndef USE_AS_STRCHRNUL
+	.align	4
+L(no_match):
+	li	r3,0
+	blr
+#endif
+
+/* We are here because strchr was called with a null byte.  */
+	.align	4
+L(null_match):
+	/* r0 has a doubleword of null bytes.  */
+
+	cmpb	r5,r12,r0     /* Compare each byte against null bytes.  */
+
+	/* Move the doublewords left and right to discard the bits that are
+	   not part of the string and bring them back as zeros.  */
+#ifdef __LITTLE_ENDIAN__
+	srd	r5,r5,r6
+	sld	r5,r5,r6
+#else
+	sld	r5,r5,r6
+	srd	r5,r5,r6
+#endif
+	cmpdi	cr7,r5,0      /* If r10 == 0, no c or null bytes
+				 have been found.  */
+	bne	cr7,L(done_null)
+
+	mtcrf   0x01,r8
+
+	/* Are we now aligned to a quadword boundary?  If so, skip to
+	   the main loop.  Otherwise, go through the alignment code.  */
+
+	bt	28,L(loop_null)
+
+	/* Handle WORD2 of pair.  */
+	ldu	r12,8(r8)
+	cmpb    r5,r12,r0
+	cmpdi	cr7,r5,0
+	bne	cr7,L(done_null)
+	b	L(loop_null)  /* We branch here (rather than falling through)
+				 to skip the nops due to heavy alignment
+				 of the loop below.  */
+
+	/* Main loop to look for the end of the string.  Since it's a
+	   small loop (< 8 instructions), align it to 32-bytes.  */
+	.p2align  5
+L(loop_null):
+	/* Load two doublewords, compare and merge in a
+	   single register for speed.  This is an attempt
+	   to speed up the null-checking process for bigger strings.  */
+	ld	r12,8(r8)
+	ldu     r11,16(r8)
+	cmpb	r5,r12,r0
+	cmpb	r10,r11,r0
+	or	r6,r5,r10
+	cmpdi	cr7,r6,0
+	beq	cr7,L(vector1)
+
+	/* OK, one (or both) of the doublewords contains a null byte.  Check
+	   the first doubleword and decrement the address in case the first
+	   doubleword really contains a null byte.  */
+
+	cmpdi	cr6,r5,0
+	addi	r8,r8,-8
+	bne	cr6,L(done_null)
+
+	/* The null byte must be in the second doubleword.  Adjust the address
+	   again and move the result of cmpb to r10 so we can calculate the
+	   pointer.  */
+
+	mr	r5,r10
+	addi	r8,r8,8
+
+	/* r5 has the output of the cmpb instruction, that is, it contains
+	   0xff in the same position as the null byte in the original
+	   doubleword from the string.  Use that to calculate the pointer.  */
+L(done_null):
+#ifdef __LITTLE_ENDIAN__
+	addi    r0,r5,-1
+	andc    r0,r0,r5
+	popcntd	r0,r0
+#else
+	cntlzd	r0,r5	      /* Count leading zeros before the match.  */
+#endif
+	srdi	r0,r0,3	      /* Convert leading zeros to bytes.  */
+	add	r3,r8,r0      /* Return address of the matching null byte.  */
+	blr
+	.p2align  5
+L(vector1):
+	addi    r3, r8, 8
+	andi.	r10, r3, 31
+	bne	cr0, L(loop_null)
+	vspltisb	v8, -1
+	vspltisb	v0, 0
+	vspltisb	v10, 3
+	lvsl	v11, r0, r0
+	vslb	v10, v11, v10
+	li	r5, 16
+L(continue1):
+	lvx	v4, 0, r3
+	lvx	v5, r3, r5
+	vcmpequb	v2, v0, v4
+	vcmpequb	v3, v0, v5
+	vor	v8, v2, v3
+	vcmpequb.	v11, v0, v8
+	addi	r3, r3, 32
+	blt	cr6, L(continue1)
+	addi	r3, r3, -32
+L(end1):
+	VBPERMQ(v2, v2, v10)
+	VBPERMQ(v3, v3, v10)
+	/* Shift each component into its correct position for merging.  */
+#ifdef __LITTLE_ENDIAN__
+	vsldoi	v3, v3, v3, 2
+#else
+	vsldoi	v2, v2, v2, 6
+	vsldoi	v3, v3, v3, 4
+#endif
+
+        /* Merge the results and move to a GPR.  */
+        vor     v4, v3, v2
+	MFVRD(r5, v4)
+#ifdef __LITTLE_ENDIAN__
+	addi	r6, r5, -1
+	andc	r6, r6, r5
+	popcntd	r6, r6
+#else
+	cntlzd	r6, r5	/* Count leading zeros before the match.  */
+#endif
+	add	r3, r3, r6	/* Compute final length.  */
+	blr
+END (FUNC_NAME)
+
+#ifndef USE_AS_STRCHRNUL
+weak_alias (strchr, index)
+libc_hidden_builtin_def (strchr)
+#endif
diff --git a/sysdeps/powerpc/powerpc64/power8/strchrnul.S b/sysdeps/powerpc/powerpc64/power8/strchrnul.S
new file mode 100644
index 0000000000..0229496872
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/power8/strchrnul.S
@@ -0,0 +1,23 @@
+/* Optimized strchrnul implementation for PowerPC64/POWER8.
+   Copyright (C) 2016 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
+   <http://www.gnu.org/licenses/>.  */
+
+#define USE_AS_STRCHRNUL 1
+#include <sysdeps/powerpc/powerpc64/power8/strchr.S>
+
+weak_alias (__strchrnul,strchrnul)
+libc_hidden_builtin_def (__strchrnul)