mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-25 22:40:05 +00:00
x86: Optimize {str|wcs}rchr-avx2
The new code unrolls the main loop slightly without adding too much overhead and minimizes the comparisons for the search CHAR. Geometric Mean of all benchmarks New / Old: 0.832 See email for all results. Full xcheck passes on x86_64 with and without multiarch enabled. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
This commit is contained in:
Noah Goldstein
parent
5307aa9c18
commit
df7e295d18
@ -27,9 +27,13 @@
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
# define VPBROADCAST vpbroadcastd
|
||||
# define VPCMPEQ vpcmpeqd
|
||||
# define VPMIN vpminud
|
||||
# define CHAR_SIZE 4
|
||||
# else
|
||||
# define VPBROADCAST vpbroadcastb
|
||||
# define VPCMPEQ vpcmpeqb
|
||||
# define VPMIN vpminub
|
||||
# define CHAR_SIZE 1
|
||||
# endif
|
||||
|
||||
# ifndef VZEROUPPER
|
||||
@ -41,196 +45,304 @@
|
||||
# endif
|
||||
|
||||
# define VEC_SIZE 32
|
||||
# define PAGE_SIZE 4096
|
||||
|
||||
.section SECTION(.text), "ax", @progbits
|
||||
ENTRY(STRRCHR)
|
||||
movd %esi, %xmm4
|
||||
movl %edi, %ecx
|
||||
movd %esi, %xmm7
|
||||
movl %edi, %eax
|
||||
/* Broadcast CHAR to YMM4. */
|
||||
VPBROADCAST %xmm4, %ymm4
|
||||
VPBROADCAST %xmm7, %ymm7
|
||||
vpxor %xmm0, %xmm0, %xmm0
|
||||
|
||||
/* Check if we may cross page boundary with one vector load. */
|
||||
andl $(2 * VEC_SIZE - 1), %ecx
|
||||
cmpl $VEC_SIZE, %ecx
|
||||
ja L(cros_page_boundary)
|
||||
/* Shift here instead of `andl` to save code size (saves a fetch
|
||||
block). */
|
||||
sall $20, %eax
|
||||
cmpl $((PAGE_SIZE - VEC_SIZE) << 20), %eax
|
||||
ja L(cross_page)
|
||||
|
||||
L(page_cross_continue):
|
||||
vmovdqu (%rdi), %ymm1
|
||||
VPCMPEQ %ymm1, %ymm0, %ymm2
|
||||
VPCMPEQ %ymm1, %ymm4, %ymm3
|
||||
vpmovmskb %ymm2, %ecx
|
||||
vpmovmskb %ymm3, %eax
|
||||
addq $VEC_SIZE, %rdi
|
||||
|
||||
testl %eax, %eax
|
||||
jnz L(first_vec)
|
||||
|
||||
/* Check end of string match. */
|
||||
VPCMPEQ %ymm1, %ymm0, %ymm6
|
||||
vpmovmskb %ymm6, %ecx
|
||||
testl %ecx, %ecx
|
||||
jnz L(return_null)
|
||||
jz L(aligned_more)
|
||||
|
||||
andq $-VEC_SIZE, %rdi
|
||||
xorl %edx, %edx
|
||||
jmp L(aligned_loop)
|
||||
|
||||
.p2align 4
|
||||
L(first_vec):
|
||||
/* Check if there is a nul CHAR. */
|
||||
testl %ecx, %ecx
|
||||
jnz L(char_and_nul_in_first_vec)
|
||||
|
||||
/* Remember the match and keep searching. */
|
||||
movl %eax, %edx
|
||||
movq %rdi, %rsi
|
||||
andq $-VEC_SIZE, %rdi
|
||||
jmp L(aligned_loop)
|
||||
|
||||
.p2align 4
|
||||
L(cros_page_boundary):
|
||||
andl $(VEC_SIZE - 1), %ecx
|
||||
andq $-VEC_SIZE, %rdi
|
||||
vmovdqa (%rdi), %ymm1
|
||||
VPCMPEQ %ymm1, %ymm0, %ymm2
|
||||
VPCMPEQ %ymm1, %ymm4, %ymm3
|
||||
vpmovmskb %ymm2, %edx
|
||||
vpmovmskb %ymm3, %eax
|
||||
shrl %cl, %edx
|
||||
shrl %cl, %eax
|
||||
addq $VEC_SIZE, %rdi
|
||||
|
||||
/* Check if there is a CHAR. */
|
||||
testl %eax, %eax
|
||||
jnz L(found_char)
|
||||
|
||||
testl %edx, %edx
|
||||
jnz L(return_null)
|
||||
|
||||
jmp L(aligned_loop)
|
||||
|
||||
.p2align 4
|
||||
L(found_char):
|
||||
testl %edx, %edx
|
||||
jnz L(char_and_nul)
|
||||
|
||||
/* Remember the match and keep searching. */
|
||||
movl %eax, %edx
|
||||
leaq (%rdi, %rcx), %rsi
|
||||
|
||||
.p2align 4
|
||||
L(aligned_loop):
|
||||
vmovdqa (%rdi), %ymm1
|
||||
VPCMPEQ %ymm1, %ymm0, %ymm2
|
||||
addq $VEC_SIZE, %rdi
|
||||
VPCMPEQ %ymm1, %ymm4, %ymm3
|
||||
vpmovmskb %ymm2, %ecx
|
||||
vpmovmskb %ymm3, %eax
|
||||
orl %eax, %ecx
|
||||
jnz L(char_nor_null)
|
||||
|
||||
vmovdqa (%rdi), %ymm1
|
||||
VPCMPEQ %ymm1, %ymm0, %ymm2
|
||||
add $VEC_SIZE, %rdi
|
||||
VPCMPEQ %ymm1, %ymm4, %ymm3
|
||||
vpmovmskb %ymm2, %ecx
|
||||
vpmovmskb %ymm3, %eax
|
||||
orl %eax, %ecx
|
||||
jnz L(char_nor_null)
|
||||
|
||||
vmovdqa (%rdi), %ymm1
|
||||
VPCMPEQ %ymm1, %ymm0, %ymm2
|
||||
addq $VEC_SIZE, %rdi
|
||||
VPCMPEQ %ymm1, %ymm4, %ymm3
|
||||
vpmovmskb %ymm2, %ecx
|
||||
vpmovmskb %ymm3, %eax
|
||||
orl %eax, %ecx
|
||||
jnz L(char_nor_null)
|
||||
|
||||
vmovdqa (%rdi), %ymm1
|
||||
VPCMPEQ %ymm1, %ymm0, %ymm2
|
||||
addq $VEC_SIZE, %rdi
|
||||
VPCMPEQ %ymm1, %ymm4, %ymm3
|
||||
vpmovmskb %ymm2, %ecx
|
||||
vpmovmskb %ymm3, %eax
|
||||
orl %eax, %ecx
|
||||
jz L(aligned_loop)
|
||||
|
||||
.p2align 4
|
||||
L(char_nor_null):
|
||||
/* Find a CHAR or a nul CHAR in a loop. */
|
||||
testl %eax, %eax
|
||||
jnz L(match)
|
||||
L(return_value):
|
||||
testl %edx, %edx
|
||||
jz L(return_null)
|
||||
movl %edx, %eax
|
||||
movq %rsi, %rdi
|
||||
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
/* Keep the first bit for each matching CHAR for bsr. */
|
||||
andl $0x11111111, %eax
|
||||
# endif
|
||||
/* Only check match with search CHAR if needed. */
|
||||
VPCMPEQ %ymm1, %ymm7, %ymm1
|
||||
vpmovmskb %ymm1, %eax
|
||||
/* Check if match before first zero. */
|
||||
blsmskl %ecx, %ecx
|
||||
andl %ecx, %eax
|
||||
jz L(ret0)
|
||||
bsrl %eax, %eax
|
||||
leaq -VEC_SIZE(%rdi, %rax), %rax
|
||||
addq %rdi, %rax
|
||||
/* We are off by 3 for wcsrchr if search CHAR is non-zero. If
|
||||
search CHAR is zero we are correct. Either way `andq
|
||||
-CHAR_SIZE, %rax` gets the correct result. */
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
andq $-CHAR_SIZE, %rax
|
||||
# endif
|
||||
L(ret0):
|
||||
L(return_vzeroupper):
|
||||
ZERO_UPPER_VEC_REGISTERS_RETURN
|
||||
|
||||
/* Returns for first vec x1/x2 have hard coded backward search
|
||||
path for earlier matches. */
|
||||
.p2align 4,, 10
|
||||
L(first_vec_x1):
|
||||
VPCMPEQ %ymm2, %ymm7, %ymm6
|
||||
vpmovmskb %ymm6, %eax
|
||||
blsmskl %ecx, %ecx
|
||||
andl %ecx, %eax
|
||||
jnz L(first_vec_x1_return)
|
||||
|
||||
.p2align 4,, 4
|
||||
L(first_vec_x0_test):
|
||||
VPCMPEQ %ymm1, %ymm7, %ymm6
|
||||
vpmovmskb %ymm6, %eax
|
||||
testl %eax, %eax
|
||||
jz L(ret1)
|
||||
bsrl %eax, %eax
|
||||
addq %r8, %rax
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
andq $-CHAR_SIZE, %rax
|
||||
# endif
|
||||
L(ret1):
|
||||
VZEROUPPER_RETURN
|
||||
|
||||
.p2align 4,, 10
|
||||
L(first_vec_x0_x1_test):
|
||||
VPCMPEQ %ymm2, %ymm7, %ymm6
|
||||
vpmovmskb %ymm6, %eax
|
||||
/* Check ymm2 for search CHAR match. If no match then check ymm1
|
||||
before returning. */
|
||||
testl %eax, %eax
|
||||
jz L(first_vec_x0_test)
|
||||
.p2align 4,, 4
|
||||
L(first_vec_x1_return):
|
||||
bsrl %eax, %eax
|
||||
leaq 1(%rdi, %rax), %rax
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
andq $-CHAR_SIZE, %rax
|
||||
# endif
|
||||
VZEROUPPER_RETURN
|
||||
|
||||
|
||||
.p2align 4,, 10
|
||||
L(first_vec_x2):
|
||||
VPCMPEQ %ymm3, %ymm7, %ymm6
|
||||
vpmovmskb %ymm6, %eax
|
||||
blsmskl %ecx, %ecx
|
||||
/* If no in-range search CHAR match in ymm3 then need to check
|
||||
ymm1/ymm2 for an earlier match (we delay checking search
|
||||
CHAR matches until needed). */
|
||||
andl %ecx, %eax
|
||||
jz L(first_vec_x0_x1_test)
|
||||
bsrl %eax, %eax
|
||||
leaq (VEC_SIZE + 1)(%rdi, %rax), %rax
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
andq $-CHAR_SIZE, %rax
|
||||
# endif
|
||||
VZEROUPPER_RETURN
|
||||
|
||||
|
||||
.p2align 4
|
||||
L(match):
|
||||
/* Find a CHAR. Check if there is a nul CHAR. */
|
||||
vpmovmskb %ymm2, %ecx
|
||||
L(aligned_more):
|
||||
/* Save original pointer if match was in VEC 0. */
|
||||
movq %rdi, %r8
|
||||
|
||||
/* Align src. */
|
||||
orq $(VEC_SIZE - 1), %rdi
|
||||
vmovdqu 1(%rdi), %ymm2
|
||||
VPCMPEQ %ymm2, %ymm0, %ymm6
|
||||
vpmovmskb %ymm6, %ecx
|
||||
testl %ecx, %ecx
|
||||
jnz L(find_nul)
|
||||
jnz L(first_vec_x1)
|
||||
|
||||
/* Remember the match and keep searching. */
|
||||
movl %eax, %edx
|
||||
vmovdqu (VEC_SIZE + 1)(%rdi), %ymm3
|
||||
VPCMPEQ %ymm3, %ymm0, %ymm6
|
||||
vpmovmskb %ymm6, %ecx
|
||||
testl %ecx, %ecx
|
||||
jnz L(first_vec_x2)
|
||||
|
||||
/* Save pointer again before realigning. */
|
||||
movq %rdi, %rsi
|
||||
jmp L(aligned_loop)
|
||||
|
||||
addq $(VEC_SIZE + 1), %rdi
|
||||
andq $-(VEC_SIZE * 2), %rdi
|
||||
.p2align 4
|
||||
L(find_nul):
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
/* Keep the first bit for each matching CHAR for bsr. */
|
||||
andl $0x11111111, %ecx
|
||||
andl $0x11111111, %eax
|
||||
# endif
|
||||
/* Mask out any matching bits after the nul CHAR. */
|
||||
movl %ecx, %r8d
|
||||
subl $1, %r8d
|
||||
xorl %ecx, %r8d
|
||||
andl %r8d, %eax
|
||||
L(first_aligned_loop):
|
||||
/* Do 2x VEC at a time. Any more and the cost of finding the
|
||||
match outweights loop benefit. */
|
||||
vmovdqa (VEC_SIZE * 0)(%rdi), %ymm4
|
||||
vmovdqa (VEC_SIZE * 1)(%rdi), %ymm5
|
||||
|
||||
VPCMPEQ %ymm4, %ymm7, %ymm6
|
||||
VPMIN %ymm4, %ymm5, %ymm8
|
||||
VPCMPEQ %ymm5, %ymm7, %ymm10
|
||||
vpor %ymm6, %ymm10, %ymm5
|
||||
VPCMPEQ %ymm8, %ymm0, %ymm8
|
||||
vpor %ymm5, %ymm8, %ymm9
|
||||
|
||||
vpmovmskb %ymm9, %eax
|
||||
addq $(VEC_SIZE * 2), %rdi
|
||||
/* No zero or search CHAR. */
|
||||
testl %eax, %eax
|
||||
/* If there is no CHAR here, return the remembered one. */
|
||||
jz L(return_value)
|
||||
bsrl %eax, %eax
|
||||
leaq -VEC_SIZE(%rdi, %rax), %rax
|
||||
VZEROUPPER_RETURN
|
||||
jz L(first_aligned_loop)
|
||||
|
||||
.p2align 4
|
||||
L(char_and_nul):
|
||||
/* Find both a CHAR and a nul CHAR. */
|
||||
addq %rcx, %rdi
|
||||
movl %edx, %ecx
|
||||
L(char_and_nul_in_first_vec):
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
/* Keep the first bit for each matching CHAR for bsr. */
|
||||
andl $0x11111111, %ecx
|
||||
andl $0x11111111, %eax
|
||||
# endif
|
||||
/* Mask out any matching bits after the nul CHAR. */
|
||||
movl %ecx, %r8d
|
||||
subl $1, %r8d
|
||||
xorl %ecx, %r8d
|
||||
andl %r8d, %eax
|
||||
/* If no zero CHAR then go to second loop (this allows us to
|
||||
throw away all prior work). */
|
||||
vpmovmskb %ymm8, %ecx
|
||||
testl %ecx, %ecx
|
||||
jz L(second_aligned_loop_prep)
|
||||
|
||||
/* Search char could be zero so we need to get the true match.
|
||||
*/
|
||||
vpmovmskb %ymm5, %eax
|
||||
testl %eax, %eax
|
||||
/* Return null pointer if the nul CHAR comes first. */
|
||||
jz L(return_null)
|
||||
bsrl %eax, %eax
|
||||
leaq -VEC_SIZE(%rdi, %rax), %rax
|
||||
jnz L(first_aligned_loop_return)
|
||||
|
||||
.p2align 4,, 4
|
||||
L(first_vec_x1_or_x2):
|
||||
VPCMPEQ %ymm3, %ymm7, %ymm3
|
||||
VPCMPEQ %ymm2, %ymm7, %ymm2
|
||||
vpmovmskb %ymm3, %eax
|
||||
vpmovmskb %ymm2, %edx
|
||||
/* Use add for macro-fusion. */
|
||||
addq %rax, %rdx
|
||||
jz L(first_vec_x0_test)
|
||||
/* NB: We could move this shift to before the branch and save a
|
||||
bit of code size / performance on the fall through. The
|
||||
branch leads to the null case which generally seems hotter
|
||||
than char in first 3x VEC. */
|
||||
salq $32, %rax
|
||||
addq %rdx, %rax
|
||||
bsrq %rax, %rax
|
||||
leaq 1(%rsi, %rax), %rax
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
andq $-CHAR_SIZE, %rax
|
||||
# endif
|
||||
VZEROUPPER_RETURN
|
||||
|
||||
.p2align 4,, 8
|
||||
L(first_aligned_loop_return):
|
||||
VPCMPEQ %ymm4, %ymm0, %ymm4
|
||||
vpmovmskb %ymm4, %edx
|
||||
salq $32, %rcx
|
||||
orq %rdx, %rcx
|
||||
|
||||
vpmovmskb %ymm10, %eax
|
||||
vpmovmskb %ymm6, %edx
|
||||
salq $32, %rax
|
||||
orq %rdx, %rax
|
||||
blsmskq %rcx, %rcx
|
||||
andq %rcx, %rax
|
||||
jz L(first_vec_x1_or_x2)
|
||||
|
||||
bsrq %rax, %rax
|
||||
leaq -(VEC_SIZE * 2)(%rdi, %rax), %rax
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
andq $-CHAR_SIZE, %rax
|
||||
# endif
|
||||
VZEROUPPER_RETURN
|
||||
|
||||
/* Search char cannot be zero. */
|
||||
.p2align 4
|
||||
L(second_aligned_loop_set_furthest_match):
|
||||
/* Save VEC and pointer from most recent match. */
|
||||
L(second_aligned_loop_prep):
|
||||
movq %rdi, %rsi
|
||||
vmovdqu %ymm6, %ymm2
|
||||
vmovdqu %ymm10, %ymm3
|
||||
|
||||
.p2align 4
|
||||
L(return_null):
|
||||
xorl %eax, %eax
|
||||
L(second_aligned_loop):
|
||||
/* Search 2x at at time. */
|
||||
vmovdqa (VEC_SIZE * 0)(%rdi), %ymm4
|
||||
vmovdqa (VEC_SIZE * 1)(%rdi), %ymm5
|
||||
|
||||
VPCMPEQ %ymm4, %ymm7, %ymm6
|
||||
VPMIN %ymm4, %ymm5, %ymm1
|
||||
VPCMPEQ %ymm5, %ymm7, %ymm10
|
||||
vpor %ymm6, %ymm10, %ymm5
|
||||
VPCMPEQ %ymm1, %ymm0, %ymm1
|
||||
vpor %ymm5, %ymm1, %ymm9
|
||||
|
||||
vpmovmskb %ymm9, %eax
|
||||
addq $(VEC_SIZE * 2), %rdi
|
||||
testl %eax, %eax
|
||||
jz L(second_aligned_loop)
|
||||
vpmovmskb %ymm1, %ecx
|
||||
testl %ecx, %ecx
|
||||
jz L(second_aligned_loop_set_furthest_match)
|
||||
vpmovmskb %ymm5, %eax
|
||||
testl %eax, %eax
|
||||
jnz L(return_new_match)
|
||||
|
||||
/* This is the hot patch. We know CHAR is inbounds and that
|
||||
ymm3/ymm2 have latest match. */
|
||||
.p2align 4,, 4
|
||||
L(return_old_match):
|
||||
vpmovmskb %ymm3, %eax
|
||||
vpmovmskb %ymm2, %edx
|
||||
salq $32, %rax
|
||||
orq %rdx, %rax
|
||||
bsrq %rax, %rax
|
||||
/* Search char cannot be zero so safe to just use lea for
|
||||
wcsrchr. */
|
||||
leaq (VEC_SIZE * -2 -(CHAR_SIZE - 1))(%rsi, %rax), %rax
|
||||
VZEROUPPER_RETURN
|
||||
|
||||
/* Last iteration also potentially has a match. */
|
||||
.p2align 4,, 8
|
||||
L(return_new_match):
|
||||
VPCMPEQ %ymm4, %ymm0, %ymm4
|
||||
vpmovmskb %ymm4, %edx
|
||||
salq $32, %rcx
|
||||
orq %rdx, %rcx
|
||||
|
||||
vpmovmskb %ymm10, %eax
|
||||
vpmovmskb %ymm6, %edx
|
||||
salq $32, %rax
|
||||
orq %rdx, %rax
|
||||
blsmskq %rcx, %rcx
|
||||
andq %rcx, %rax
|
||||
jz L(return_old_match)
|
||||
bsrq %rax, %rax
|
||||
/* Search char cannot be zero so safe to just use lea for
|
||||
wcsrchr. */
|
||||
leaq (VEC_SIZE * -2 -(CHAR_SIZE - 1))(%rdi, %rax), %rax
|
||||
VZEROUPPER_RETURN
|
||||
|
||||
.p2align 4,, 4
|
||||
L(cross_page):
|
||||
movq %rdi, %rsi
|
||||
andq $-VEC_SIZE, %rsi
|
||||
vmovdqu (%rsi), %ymm1
|
||||
VPCMPEQ %ymm1, %ymm0, %ymm6
|
||||
vpmovmskb %ymm6, %ecx
|
||||
/* Shift out zero CHAR matches that are before the begining of
|
||||
src (rdi). */
|
||||
shrxl %edi, %ecx, %ecx
|
||||
testl %ecx, %ecx
|
||||
jz L(page_cross_continue)
|
||||
VPCMPEQ %ymm1, %ymm7, %ymm1
|
||||
vpmovmskb %ymm1, %eax
|
||||
|
||||
/* Shift out search CHAR matches that are before the begining of
|
||||
src (rdi). */
|
||||
shrxl %edi, %eax, %eax
|
||||
blsmskl %ecx, %ecx
|
||||
/* Check if any search CHAR match in range. */
|
||||
andl %ecx, %eax
|
||||
jz L(ret2)
|
||||
bsrl %eax, %eax
|
||||
addq %rdi, %rax
|
||||
# ifdef USE_AS_WCSRCHR
|
||||
andq $-CHAR_SIZE, %rax
|
||||
# endif
|
||||
L(ret2):
|
||||
VZEROUPPER_RETURN
|
||||
END(STRRCHR)
|
||||
#endif
|
||||
|
||||
Loading…
Reference in New Issue
Block a user