Betrayed by a bitfield

“Developers tend to fear compiler bugs, and for good reason:
such bugs can be hard to find and hard to work around. They can
leave traps in a compiled program that spring on users at bad
times. Things can get even worse if one person’s compiler bug is
seen by the compiler’s developer as a feature – such issues have a
tendency to never get fixed. It is possible that just this kind of
feature has turned up in GCC, with unknown impact on the
kernel.

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