C optimizer bug?

[bh.atari%rand-relay at sri-unix.UUCP]

From:  Brian Harvey <bh.atari at rand-relay>

The following was sent to me by one of our users.  I haven't played with
it myself, but was wondering whether this situation is familiar to
anyone, and if there is a known fix.  Please reply directly to
	bh.atari at rand-relay
since I don't subscribe to u-w.  Tnx.

Script started on Tue Feb 14 05:57:54 1984
Warning: no access to tty; thus no job control in this shell...
% 
% 
% cat bug.c
/*
** this file compiles with different results depending on
** whether or not the c optimizer is used.
*/

main()
{
    int     i;

    i = ((int) 1.0) & 0xff;

    printf ("i = 0x%x\n", i);
}

% 
% 
% cc bug.c -o nobug
% nobug
i = 0x1
% cc -O bug.c -o bug
% bug
i = 0x80
% 
% 
% cc -S bug.c
% t bug.s
LL0:
	.data
	.text
	.align	1
	.globl	_main
_main:
	.word	L12
	jbr 	L14
L15:
	.data
	.align	2
L16:
	.double	0d1.00000000000000000000e+00
	.text
	cvtdl	L16,r0
	bicl2	$-256,r0
	movl	r0,-4(fp)
	.data	1
L18:
	.ascii	"i = 0x%x\12\0"
	.text
	pushl	-4(fp)
	pushl	$L18
	calls	$2,_printf
	ret
	.set	L12,0x0
L14:
	subl2	$4,sp
	jbr 	L15
	.data
% cc -O -S bug.c
% cat bug.s
.data
.text
LL0:.align	1
.globl	_main
.data
.align	2
L16:.double	0d1.00000000000000000000e+00
.text
.data	1
L18:.ascii	"i = 0x%x\12\0"
.text
.set	L12,0x0
.data
.text
_main:.word	L12
subl2	$4,sp
movzbl	L16,-4(fp)
pushl	-4(fp)
pushal	L18
calls	$2,_printf
ret

% 
script done on Tue Feb 14 06:00:31 1984