Hi Kyrill, > SVE2 does the whole thing in far fewer instructions and, being > vector-length agnostic, keeps scaling on implementations wider than > 128 bits. Every 128-bit segment of the needle vector holds the four > characters, so a single MATCH reports set membership for the whole > vector, and MATCH sets the condition flags directly, so the loop branch > needs no reduction. BRKB and INCP then convert the result predicate > straight into a pointer increment.
Looks great now - just 2 minor things below (but it's fine for commit either way). You might also want to try out my optimized AdvSIMD version at https://gcc.gnu.org/pipermail/gcc-patches/2026-August/727347.html :-) Cheers, Wilco +static const uchar * __attribute__ ((target ("+sve2"))) +search_line_sve2 (const uchar *s, const uchar *end) +{ + /* Order within a segment is irrelevant to MATCH, which tests set + membership, so this needs no adjustment for big-endian. */ + const uint32_t chars = ((uint32_t) '\n' | ((uint32_t) '\r' << 8) + | ((uint32_t) '\\' << 16) | ((uint32_t) '?' << 24)); + const svuint8_t needles = svreinterpret_u8_u32 (svdup_n_u32 (chars)); + const svbool_t all = svptrue_b8 (); + const uint64_t vl = svcntb (); + svuint8_t data; + svbool_t match; + uintptr_t limit; + + /* The last address from which a whole vector still lies below END. + Computed on integers so that a buffer shorter than a vector simply + skips the loop. */ + limit = (uintptr_t) end; + limit = limit >= vl ? limit - vl : 0; Why not: limit = (uintptr_t) end & -vl; ? That's simpler and allows the loop to process 0.5VL more data near the end. + while ((uintptr_t) s <= limit) + { + data = svld1_u8 (all, s); + match = svmatch_u8 (all, data, needles); + if (svptest_any (all, match)) + return s + svcntp_b8 (all, svbrkb_b_z (all, match)); + s += vl; + } + + /* What is left, up to and including *END, which _cpp_convert_input + forces to a newline. That guarantees a match, so no further test is + needed. */ + svbool_t pg = svwhilele_b8_u64 ((uint64_t) (uintptr_t) s, + (uint64_t) (uintptr_t) end); Why the double casting? It could just be svwhilele_b8_u64 ((uintptr_t) s, (uintptr_t) end); + data = svld1_u8 (pg, s); + match = svmatch_u8 (pg, data, needles); + return s + svcntp_b8 (pg, svbrkb_b_z (pg, match)); +}
