On Sat, Aug 27, 2022 at 1:24 AM Nathan Bossart <nathandboss...@gmail.com> wrote: > > Here is a rebased patch set that applies to HEAD.
0001: #define USE_NO_SIMD typedef uint64 Vector8; +typedef uint64 Vector32; #endif I don't forsee any use of emulating vector registers with uint64 if they only hold two ints. I wonder if it'd be better if all vector32 functions were guarded with #ifndef NO_USE_SIMD. (I wonder if declarations without definitions cause warnings...) + * NB: This function assumes that each lane in the given vector either has all + * bits set or all bits zeroed, as it is mainly intended for use with + * operations that produce such vectors (e.g., vector32_eq()). If this + * assumption is not true, this function's behavior is undefined. + */ Hmm? Also, is_highbit_set() already has uses same intrinsic and has the same intended effect, since we only care about the boolean result. 0002: -#elif defined(USE_SSE2) +#elif defined(USE_SSE2) || defined(USE_NEON) I think we can just say #else. -#if defined(USE_SSE2) - __m128i sub; +#ifndef USE_NO_SIMD + Vector8 sub; +#elif defined(USE_NEON) + + /* use the same approach as the USE_SSE2 block above */ + sub = vqsubq_u8(v, vector8_broadcast(c)); + result = vector8_has_zero(sub); I think we should invent a helper that does saturating subtraction and call that, inlining the sub var so we don't need to mess with it further. Otherwise seems fine. -- John Naylor EDB: http://www.enterprisedb.com
