From cb93efbe9ee116e42c4f8b7cc03e007761fdfce0 Mon Sep 17 00:00:00 2001
From: ValarDragon <dojha12@gmail.com>
Date: Mon, 24 Aug 2020 22:29:33 -0500
Subject: [PATCH] Fix is_power_of_two for n > 2^32

Closes #34
---
 CHANGELOG.md           | 1 +
 libff/common/utils.cpp | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1988d537..103c5047 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ _Special thanks to all downstream projects upstreaming their patches!_
 - #52 Change default build flags to work with Mac OS, and add instructions for finding macOS openSSL installation
 
 ### Bug fixes
+- #54 Fix is_power_of_two for n > 2^32
 - #19 Fix is_little_endian always returning true
 - #20 Fix operator+ not contributing to alt_bn_128 profiling opcount 
 - #26 Remove unused warnings in release build
diff --git a/libff/common/utils.cpp b/libff/common/utils.cpp
index eb6640b0..f52a431b 100755
--- a/libff/common/utils.cpp
+++ b/libff/common/utils.cpp
@@ -16,6 +16,8 @@
 
 namespace libff {
 
+/** Round n to the next power of two.
+ *  If n is a power of two, return n  */
 size_t get_power_of_two(size_t n)
 {
     n--;
@@ -24,6 +26,7 @@ size_t get_power_of_two(size_t n)
     n |= n >> 4;
     n |= n >> 8;
     n |= n >> 16;
+    n |= n >> 32;
     n++;
 
     return n;