[libcxx-commits] [libcxx] linear_congruential_engine: Fixes for __lce_alg_picker (PR #81080)

[via libcxx-commits]

https://github.com/LRFLEW updated https://github.com/llvm/llvm-project/pull/81080

>From c3137ea53f3c90d7336df4562ec8496170382b21 Mon Sep 17 00:00:00 2001
From: LRFLEW <LRFLEW at aol.com>
Date: Wed, 7 Feb 2024 15:04:27 -0600
Subject: [PATCH] Fixes for __lce_alg_picker

Fixes _OverflowOK and the static_assert to actually check for what they're intended to check.
---
 libcxx/include/__random/linear_congruential_engine.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libcxx/include/__random/linear_congruential_engine.h b/libcxx/include/__random/linear_congruential_engine.h
index 51f6b248d8f974..fe9cb909b74d21 100644
--- a/libcxx/include/__random/linear_congruential_engine.h
+++ b/libcxx/include/__random/linear_congruential_engine.h
@@ -31,10 +31,10 @@ template <unsigned long long __a,
           unsigned long long __m,
           unsigned long long _Mp,
           bool _MightOverflow = (__a != 0 && __m != 0 && __m - 1 > (_Mp - __c) / __a),
-          bool _OverflowOK    = ((__m | (__m - 1)) > __m),                    // m = 2^n
+          bool _OverflowOK    = ((__m & (__m - 1)) == 0ull),                  // m = 2^n
           bool _SchrageOK     = (__a != 0 && __m != 0 && __m % __a <= __m / __a)> // r <= q
 struct __lce_alg_picker {
-  static_assert(__a != 0 || __m != 0 || !_MightOverflow || _OverflowOK || _SchrageOK,
+  static_assert(!_MightOverflow || _OverflowOK || _SchrageOK,
                 "The current values of a, c, and m cannot generate a number "
                 "within bounds of linear_congruential_engine.");