From 3817435d200af5da954d505ae66245662dea064c Mon Sep 17 00:00:00 2001 From: Nathan Bossart Date: Fri, 15 Mar 2024 12:26:26 -0500 Subject: [PATCH v3 1/3] pg_lfind32: process "tail" with SIMD intructions --- src/include/port/pg_lfind.h | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/src/include/port/pg_lfind.h b/src/include/port/pg_lfind.h index b8dfa66eef..9d21284724 100644 --- a/src/include/port/pg_lfind.h +++ b/src/include/port/pg_lfind.h @@ -103,7 +103,7 @@ pg_lfind32(uint32 key, uint32 *base, uint32 nelem) const uint32 nelem_per_iteration = 4 * nelem_per_vector; /* round down to multiple of elements per iteration */ - const uint32 tail_idx = nelem & ~(nelem_per_iteration - 1); + uint32 tail_idx = nelem & ~(nelem_per_iteration - 1); #if defined(USE_ASSERT_CHECKING) bool assert_result = false; @@ -117,9 +117,11 @@ pg_lfind32(uint32 key, uint32 *base, uint32 nelem) break; } } + i = 0; #endif - for (i = 0; i < tail_idx; i += nelem_per_iteration) +retry: + for (; i < tail_idx; i += nelem_per_iteration) { Vector32 vals1, vals2, @@ -157,6 +159,16 @@ pg_lfind32(uint32 key, uint32 *base, uint32 nelem) return true; } } + + if (i == nelem) + return false; + else if (tail_idx > 0) + { + tail_idx = nelem; + i = nelem - nelem_per_iteration; + goto retry; + } + #endif /* ! USE_NO_SIMD */ /* Process the remaining elements one at a time. */ -- 2.25.1