runtime: checkptr incorrectly -race flagging when using &^ arithmetic [1.15 backport] #40934
Description
@mdempsky requested issue #40917 to be considered for backport to the next 1.15 minor release.
@gopherbot Please consider for backport to Go 1.15. See my rationale for/against at #40917 (comment). Also, that this affected real user code at #40917 (comment).