From mboxrd@z Thu Jan  1 00:00:00 1970
To: 9fans@cse.psu.edu
Subject: Re: [9fans] another compiler bug (another try to send this coherently)
From: rog@vitanuova.com
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Date: Mon, 16 Jul 2001 12:13:04 +0100
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> How do you figure that?  The promoted tab[0] (signed int) or x
> left-shifted 24 places sets the sign bit, and right-shifting a
> negative value is implementation-defined.

implementation-defined implies the result is at least consistent across
a particular implementation.  the example that was given shows that
that isn't the case (if the unsigned char is indeed being promoted to
signed int, which it isn't, as the compiler error messages for the
following code imply:)

#include <u.h>
#include <libc.h>

int
main(void)
{
         static unsigned char tab[1] = { 0x80 };
	char *z;
	z = tab[0] << 24 >> 31;
}