b68cfb3330
Upstream commit: b2f32e746492615a6eb3e66fac1e766e32e8deb1
- malloc: Simplify implementation of __malloc_assert
- Update syscall-names.list for Linux 5.18
- x86: Add missing IS_IN (libc) check to strncmp-sse4_2.S
- x86: Move mem{p}{mov|cpy}_{chk_}erms to its own file
- x86: Move and slightly improve memset_erms
- x86: Add definition for __wmemset_chk AVX2 RTM in ifunc impl list
- x86: Put wcs{n}len-sse4.1 in the sse4.1 text section
- x86: Align entry for memrchr to 64-bytes.
- x86: Add BMI1/BMI2 checks for ISA_V3 check
- x86: Cleanup bounds checking in large memcpy case
- x86: Add bounds `x86_non_temporal_threshold`
- x86: Add sse42 implementation to strcmp's ifunc
- x86: Fix misordered logic for setting `rep_movsb_stop_threshold`
- x86: Align varshift table to 32-bytes
- x86: ZERO_UPPER_VEC_REGISTERS_RETURN_XTEST expect no transactions
- x86: Shrink code size of memchr-evex.S
- x86: Shrink code size of memchr-avx2.S
- x86: Optimize memrchr-avx2.S
- x86: Optimize memrchr-evex.S
- x86: Optimize memrchr-sse2.S
- x86: Add COND_VZEROUPPER that can replace vzeroupper if no `ret`
- x86: Create header for VEC classes in x86 strings library
- x86_64: Add strstr function with 512-bit EVEX
- x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT
- x86_64: Implement evex512 version of strlen, strnlen, wcslen and wcsnlen
- x86_64: Remove bzero optimization
- x86_64: Remove end of line trailing spaces
- nptl: Fix ___pthread_unregister_cancel_restore asynchronous restore
- linux: Fix mq_timereceive check for 32 bit fallback code (BZ 29304)
131 lines
3.4 KiB
Diff
131 lines
3.4 KiB
Diff
commit 3c87383a20daff9a230439e31b778716bfed4d8b
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Author: Noah Goldstein <goldstein.w.n@gmail.com>
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Date: Mon Jun 6 21:11:34 2022 -0700
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x86: Shrink code size of memchr-evex.S
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This is not meant as a performance optimization. The previous code was
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far to liberal in aligning targets and wasted code size unnecissarily.
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The total code size saving is: 64 bytes
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There are no non-negligible changes in the benchmarks.
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Geometric Mean of all benchmarks New / Old: 1.000
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Full xcheck passes on x86_64.
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Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
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(cherry picked from commit 56da3fe1dd075285fa8186d44b3c28e68c687e62)
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diff --git a/sysdeps/x86_64/multiarch/memchr-evex.S b/sysdeps/x86_64/multiarch/memchr-evex.S
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index 4d0ed6d136f099e1..68381c99a4948134 100644
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--- a/sysdeps/x86_64/multiarch/memchr-evex.S
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+++ b/sysdeps/x86_64/multiarch/memchr-evex.S
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@@ -88,7 +88,7 @@
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# define PAGE_SIZE 4096
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.section SECTION(.text),"ax",@progbits
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-ENTRY (MEMCHR)
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+ENTRY_P2ALIGN (MEMCHR, 6)
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# ifndef USE_AS_RAWMEMCHR
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/* Check for zero length. */
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test %RDX_LP, %RDX_LP
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@@ -131,22 +131,24 @@ L(zero):
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xorl %eax, %eax
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ret
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- .p2align 5
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+ .p2align 4
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L(first_vec_x0):
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- /* Check if first match was before length. */
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- tzcntl %eax, %eax
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- xorl %ecx, %ecx
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- cmpl %eax, %edx
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- leaq (%rdi, %rax, CHAR_SIZE), %rax
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- cmovle %rcx, %rax
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+ /* Check if first match was before length. NB: tzcnt has false data-
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+ dependency on destination. eax already had a data-dependency on esi
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+ so this should have no affect here. */
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+ tzcntl %eax, %esi
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+# ifdef USE_AS_WMEMCHR
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+ leaq (%rdi, %rsi, CHAR_SIZE), %rdi
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+# else
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+ addq %rsi, %rdi
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+# endif
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+ xorl %eax, %eax
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+ cmpl %esi, %edx
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+ cmovg %rdi, %rax
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ret
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-# else
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- /* NB: first_vec_x0 is 17 bytes which will leave
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- cross_page_boundary (which is relatively cold) close enough
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- to ideal alignment. So only realign L(cross_page_boundary) if
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- rawmemchr. */
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- .p2align 4
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# endif
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+
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+ .p2align 4
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L(cross_page_boundary):
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/* Save pointer before aligning as its original value is
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necessary for computer return address if byte is found or
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@@ -400,10 +402,14 @@ L(last_2x_vec):
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L(zero_end):
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ret
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+L(set_zero_end):
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+ xorl %eax, %eax
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+ ret
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.p2align 4
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L(first_vec_x1_check):
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- tzcntl %eax, %eax
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+ /* eax must be non-zero. Use bsfl to save code size. */
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+ bsfl %eax, %eax
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/* Adjust length. */
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subl $-(CHAR_PER_VEC * 4), %edx
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/* Check if match within remaining length. */
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@@ -412,9 +418,6 @@ L(first_vec_x1_check):
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/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count. */
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leaq VEC_SIZE(%rdi, %rax, CHAR_SIZE), %rax
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ret
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-L(set_zero_end):
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- xorl %eax, %eax
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- ret
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.p2align 4
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L(loop_4x_vec_end):
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@@ -464,7 +467,7 @@ L(loop_4x_vec_end):
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# endif
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ret
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- .p2align 4
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+ .p2align 4,, 10
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L(last_vec_x1_return):
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tzcntl %eax, %eax
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# if defined USE_AS_WMEMCHR || RET_OFFSET != 0
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@@ -496,6 +499,7 @@ L(last_vec_x3_return):
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# endif
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# ifndef USE_AS_RAWMEMCHR
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+ .p2align 4,, 5
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L(last_4x_vec_or_less_cmpeq):
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VPCMP $0, (VEC_SIZE * 5)(%rdi), %YMMMATCH, %k0
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kmovd %k0, %eax
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@@ -546,7 +550,7 @@ L(last_4x_vec):
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# endif
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andl %ecx, %eax
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jz L(zero_end2)
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- tzcntl %eax, %eax
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+ bsfl %eax, %eax
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leaq (VEC_SIZE * 4)(%rdi, %rax, CHAR_SIZE), %rax
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L(zero_end2):
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ret
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@@ -562,6 +566,6 @@ L(last_vec_x3):
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leaq (VEC_SIZE * 3)(%rdi, %rax, CHAR_SIZE), %rax
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ret
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# endif
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-
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+ /* 7 bytes from next cache line. */
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END (MEMCHR)
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#endif
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