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| author | Wilco Dijkstra <wilco.dijkstra@arm.com> | 2023-01-11 13:51:17 +0000 |
|---|---|---|
| committer | Wilco Dijkstra <wilco.dijkstra@arm.com> | 2024-04-08 17:26:23 +0100 |
| commit | 65c4bb41b6e3db2ca81851e0e4e0f4e2e71c8e36 (patch) | |
| tree | 14b911b0509eee69a06c9be19667bba76688d2e2 | |
| parent | 23be6f897ea1d613516d09951368200d37a81ee7 (diff) | |
| download | glibc-65c4bb41b6e3db2ca81851e0e4e0f4e2e71c8e36.tar.gz glibc-65c4bb41b6e3db2ca81851e0e4e0f4e2e71c8e36.tar.xz glibc-65c4bb41b6e3db2ca81851e0e4e0f4e2e71c8e36.zip | |
AArch64: Optimize memrchr
Optimize the main loop - large strings are 43% faster on modern CPUs. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> (cherry picked from commit 00776241776e67fc666b896c1e85770f4f3ec1e1)
| -rw-r--r-- | sysdeps/aarch64/memrchr.S | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/sysdeps/aarch64/memrchr.S b/sysdeps/aarch64/memrchr.S index 5179320720..428af51f70 100644 --- a/sysdeps/aarch64/memrchr.S +++ b/sysdeps/aarch64/memrchr.S @@ -26,7 +26,6 @@ * MTE compatible. */ -/* Arguments and results. */ #define srcin x0 #define chrin w1 #define cntin x2 @@ -77,31 +76,34 @@ ENTRY (__memrchr) csel result, result, xzr, hi ret + nop L(start_loop): - sub tmp, end, src - subs cntrem, cntin, tmp + subs cntrem, src, srcin b.ls L(nomatch) /* Make sure that it won't overread by a 16-byte chunk */ - add tmp, cntrem, 15 - tbnz tmp, 4, L(loop32_2) + sub cntrem, cntrem, 1 + tbz cntrem, 4, L(loop32_2) + add src, src, 16 - .p2align 4 + .p2align 5 L(loop32): - ldr qdata, [src, -16]! + ldr qdata, [src, -32]! cmeq vhas_chr.16b, vdata.16b, vrepchr.16b umaxp vend.16b, vhas_chr.16b, vhas_chr.16b /* 128->64 */ fmov synd, dend cbnz synd, L(end) L(loop32_2): - ldr qdata, [src, -16]! + ldr qdata, [src, -16] subs cntrem, cntrem, 32 cmeq vhas_chr.16b, vdata.16b, vrepchr.16b - b.ls L(end) + b.lo L(end_2) umaxp vend.16b, vhas_chr.16b, vhas_chr.16b /* 128->64 */ fmov synd, dend cbz synd, L(loop32) +L(end_2): + sub src, src, 16 L(end): shrn vend.8b, vhas_chr.8h, 4 /* 128->64 */ fmov synd, dend |