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From: DJ Delorie <dj@redhat.com>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: libc-alpha@sourceware.org
Subject: Re: [patch] Use unsigned constants for ICMP6 filters [BZ #22489]
In-Reply-To: <87imhondz7.fsf@linux-m68k.org> (message from Andreas Schwab on
 Sat, 25 Apr 2020 10:53:16 +0200)
Date: Sat, 25 Apr 2020 13:15:23 -0400
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Andreas Schwab <schwab@linux-m68k.org> writes:
> That explanation doesn't make sense.  This has nothing to do with
> signedness of bitfields, it is about shifting a value out of its range.

The struct has this:

    uint32_t icmp6_filt[8];

It's not a "gcc bitfield" it's an "icmp filter bitfield"

The logic in the test case boils down to:

  (uint32_t) icmp6_filt[]  &=3D  (int) -65

GCC complains that -65 doesn't fit in "uint32_t" and was converted to
(unsigned) 0xffffffbf.