From 5f200821e1d4863a2b9b5f334e514ce8f6be9a5b Mon Sep 17 00:00:00 2001
From: Stefan Karpinski <stefan@karpinski.org>
Date: Tue, 20 Feb 2024 12:05:16 -0500
Subject: [PATCH] jl_rng_split: permute state by multiply instead of add

Issue raised here:

https://discourse.julialang.org/t/linear-relationship-between-xoshiro-tasks/110454
---
 src/task.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/task.c b/src/task.c
index a1e8dabb89f9dc..96fc22fb5e1b04 100644
--- a/src/task.c
+++ b/src/task.c
@@ -1079,7 +1079,7 @@ void jl_rng_split(uint64_t dst[JL_RNG_SIZE], uint64_t src[JL_RNG_SIZE]) JL_NOTSA
         p ^= p >> ((p >> 59) + 5);
         p *= m[i];
         p ^= p >> 43;
-        dst[i] = src[i] + p; // SplitMix dot product
+        dst[i] = src[i] * (p | 1); // multiplicative permutation
     }
 }