[gcc r12-1757] libstdc++: Fix comment in chrono::year::is_leap()

[Jonathan Wakely]

https://gcc.gnu.org/g:4a404f66b09d661bdc60e7e0d5d08f00c4e194db

commit r12-1757-g4a404f66b09d661bdc60e7e0d5d08f00c4e194db
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Jun 23 18:50:03 2021 +0100

    libstdc++: Fix comment in chrono::year::is_leap()
    
    libstdc++-v3/ChangeLog:
    
            * include/std/chrono (chrono::year::is_leap()): Fix incorrect
            logic in comment.

Diff:
---
 libstdc++-v3/include/std/chrono | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/include/std/chrono b/libstdc++-v3/include/std/chrono
index 863b6a27bdf..0b597be1944 100644
--- a/libstdc++-v3/include/std/chrono
+++ b/libstdc++-v3/include/std/chrono
@@ -1606,8 +1606,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	// [1] https://github.com/cassioneri/calendar
 	// [2] https://accu.org/journals/overload/28/155/overload155.pdf#page=16
 
-	// Furthermore, if y%100 != 0, then y%400==0 is equivalent to y%16==0,
-	// so we can rearrange the expression to (mult_100 ? y % 4 : y % 16)==0
+	// Furthermore, if y%100 == 0, then y%400==0 is equivalent to y%16==0,
+	// so we can simplify it to (!mult_100 && y % 4 == 0) || y % 16 == 0,
 	// which is equivalent to (y & (mult_100 ? 15 : 3)) == 0.
 	// See https://gcc.gnu.org/pipermail/libstdc++/2021-June/052815.html