diff options
| author | erifan01 <eric.fang@arm.com> | 2018-04-17 07:37:38 +0000 |
|---|---|---|
| committer | Cherry Zhang <cherryyz@google.com> | 2018-04-24 20:21:08 +0000 |
| commit | d4e936cfd622de322dc93f69144c68bb4c133e21 (patch) | |
| tree | 4b4fe7a1b9308d7673ae8447c102cb4ef3b67cdc /src | |
| parent | 5d4267e4803436e17b87e88b13dc79e528299634 (diff) | |
| download | go-d4e936cfd622de322dc93f69144c68bb4c133e21.tar.xz | |
internal/bytealg: optimize IndexString on arm64
This CL adjusts the order of the branch instructions of the
code to make it easier for the LIKELY branch to happen.
Benchmarks:
name old time/op new time/op delta
pkg:strings goos:linux goarch:arm64
IndexHard2-8 2.17ms ± 1% 1.23ms ± 0% -43.34% (p=0.008 n=5+5)
CountHard2-8 2.13ms ± 1% 1.21ms ± 2% -43.31% (p=0.008 n=5+5)
pkg:bytes goos:linux goarch:arm64
IndexRune/4M-8 661µs ±22% 513µs ± 0% -22.32% (p=0.008 n=5+5)
IndexEasy/4M-8 672µs ±23% 513µs ± 0% -23.71% (p=0.016 n=5+4)
Change-Id: Ib96f095edf77747edc8a971e79f5c1428e5808ce
Reviewed-on: https://go-review.googlesource.com/109015
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Diffstat (limited to 'src')
| -rw-r--r-- | src/internal/bytealg/index_arm64.s | 74 |
1 files changed, 35 insertions, 39 deletions
diff --git a/src/internal/bytealg/index_arm64.s b/src/internal/bytealg/index_arm64.s index 6c93ef3ce8..02eb658fd0 100644 --- a/src/internal/bytealg/index_arm64.s +++ b/src/internal/bytealg/index_arm64.s @@ -41,12 +41,12 @@ len_8: MOVD (R2), R5 loop_8: // R6 contains substring for comparison + CMP R4, R0 + BHI not_found MOVD.P 1(R0), R6 CMP R5, R6 - BEQ found - CMP R4, R0 - BLS loop_8 - JMP not_found + BNE loop_8 + B found len_2_7: TBZ $2, R3, len_2_3 TBZ $1, R3, len_4_5 @@ -57,31 +57,29 @@ len_7: // 1-byte overlap with R5 MOVWU 3(R2), R6 loop_7: + CMP R4, R0 + BHI not_found MOVWU.P 1(R0), R3 CMP R5, R3 - BNE not_equal_7 + BNE loop_7 MOVWU 2(R0), R3 CMP R6, R3 - BEQ found -not_equal_7: - CMP R4, R0 - BLS loop_7 - JMP not_found + BNE loop_7 + B found len_6: // R5 and R6 contain 6-byte sep MOVWU (R2), R5 MOVHU 4(R2), R6 loop_6: + CMP R4, R0 + BHI not_found MOVWU.P 1(R0), R3 CMP R5, R3 - BNE not_equal_6 + BNE loop_6 MOVHU 3(R0), R3 CMP R6, R3 - BEQ found -not_equal_6: - CMP R4, R0 - BLS loop_6 - JMP not_found + BNE loop_6 + B found len_4_5: TBZ $0, R3, len_4 len_5: @@ -89,26 +87,25 @@ len_5: MOVWU (R2), R5 MOVBU 4(R2), R7 loop_5: + CMP R4, R0 + BHI not_found MOVWU.P 1(R0), R3 CMP R5, R3 - BNE not_equal_5 + BNE loop_5 MOVBU 3(R0), R3 CMP R7, R3 - BEQ found -not_equal_5: - CMP R4, R0 - BLS loop_5 - JMP not_found + BNE loop_5 + B found len_4: // R5 contains 4-byte sep MOVWU (R2), R5 loop_4: + CMP R4, R0 + BHI not_found MOVWU.P 1(R0), R6 CMP R5, R6 - BEQ found - CMP R4, R0 - BLS loop_4 - JMP not_found + BNE loop_4 + B found len_2_3: TBZ $0, R3, len_2 len_3: @@ -116,30 +113,29 @@ len_3: MOVHU (R2), R6 MOVBU 2(R2), R7 loop_3: + CMP R4, R0 + BHI not_found MOVHU.P 1(R0), R3 CMP R6, R3 - BNE not_equal_3 + BNE loop_3 MOVBU 1(R0), R3 CMP R7, R3 - BEQ found -not_equal_3: - CMP R4, R0 - BLS loop_3 - JMP not_found + BNE loop_3 + B found len_2: // R5 contains 2-byte sep MOVHU (R2), R5 loop_2: + CMP R4, R0 + BHI not_found MOVHU.P 1(R0), R6 CMP R5, R6 - BEQ found - CMP R4, R0 - BLS loop_2 -not_found: - MOVD $-1, R0 - MOVD R0, (R9) - RET + BNE loop_2 found: SUB R8, R0, R0 MOVD R0, (R9) RET +not_found: + MOVD $-1, R0 + MOVD R0, (R9) + RET |