From f33b717a85363e067316c133a542559d2f4aaeca Mon Sep 17 00:00:00 2001 From: Jim Posen Date: Sun, 13 May 2018 12:00:02 -0700 Subject: [PATCH] blockfilter: Optimization on compilers with int128 support. --- src/blockfilter.cpp | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/blockfilter.cpp b/src/blockfilter.cpp index 124cbcfd92..38fcfacf7f 100644 --- a/src/blockfilter.cpp +++ b/src/blockfilter.cpp @@ -52,6 +52,9 @@ static uint64_t GolombRiceDecode(BitStreamReader& bitreader, uint8_t P) // See: https://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/ static uint64_t MapIntoRange(uint64_t x, uint64_t n) { +#ifdef __SIZEOF_INT128__ + return (static_cast(x) * static_cast(n)) >> 64; +#else // To perform the calculation on 64-bit numbers without losing the // result to overflow, split the numbers into the most significant and // least significant 32 bits and perform multiplication piece-wise. @@ -70,6 +73,7 @@ static uint64_t MapIntoRange(uint64_t x, uint64_t n) uint64_t mid34 = (bd >> 32) + (bc & 0xFFFFFFFF) + (ad & 0xFFFFFFFF); uint64_t upper64 = ac + (bc >> 32) + (ad >> 32) + (mid34 >> 32); return upper64; +#endif } uint64_t GCSFilter::HashToRange(const Element& element) const