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From: tkacik@rphroy.UUCP (Tom Tkacik)
Newsgroups: gnu.gcc.bug
Subject: gcc-1.28 generates wrong code for unsigned short to int
Keywords: AT&T UnixPC
Message-ID: <2501@rphroy.UUCP>
Date: 3 Oct 88 14:19:27 GMT
Organization: GM Research Labs, Warren, MI
Lines: 97

PROBLEM: Gcc-1.28, (when not optimizing), produces
	incorrect code for moves from an unsigned short
	to either an int or an unsigned int.
	With the optimizer on, the correct code is emitted.
	(Does this happen on all versions, or only mine?)

	Tom Tkacik
	{umix!mcf, uunet!edsews}!rphroy!tetnix!tet

SYSTEM: AT&T UnixPC   UNIX: SYSV.?  (ver 3.5)

CONFIGURATION FILES: standard for the UnixPC
	tm.h         ----> tm-3b1.h
	md   	     ----> m68k.md
	aux-output.c ----> output-m68k.c

COMMAND: gcc -v -S -gg bug.c
	The -gg option is for aiding in reading the output file.
	A program compiled with -gg cannot be assembled on the UnixPC.

VERSION:
gcc version 1.28
 /usr/local/lib/gcc-cpp -v -undef -D__GNU__ -D__GNUC__ -Dmc68k -Dunix -Dunixpc bug.c /tmp/cca03586.cpp
GNU CPP version 1.28
 /usr/local/lib/gcc-cc1 /tmp/cca03586.cpp -quiet -dumpbase bug.c -version -symout /tmp/cca03586.sym -o bug.s
GNU C version 1.28 (68k, SGS/AT&T unixpc syntax) compiled by GNU C version 1.28.

---------------------------------------------------------------
/* bug.c -- gcc makes two errors in this code */

unsigned int ui;
         int i;
unsigned short us;
         short s;

f()
{
	i = s;
	i = us;		/* gcc gets this wrong */
	ui = s;
	ui = us;	/* this also */
}
---------------------------------------------------------------

	file	"bug.c"
.text 0
.gdbbeg 0
.gdbbeg 1
Ltext:	.stabs "bug.c",100,0,0,Ltext
.data 0
Ldata:
	lcomm Lbss,0
.gdbsym Ldata,52
.gdbsym Lbss,56
text
	even
	global f
f:
	.gdbbeg 2
	.gdbline 0,9
	link.w %a6,&0
	mov.l %d2,-(%sp)
	.gdbline 0,10
	mov.w s,%a0	<---- short to int is correct
	mov.l %a0,i
	.gdbline 0,11
	mov.w us,%d2	<---- unsigned short to int is wrong
	clr.l i
	mov.l i,%d0
	mov.w %d2,%d0
	mov.l %d0,%d0
	.gdbline 0,12
	mov.w s,%a0	<---- short to unsigned is correct
	mov.l %a0,ui
	.gdbline 0,13
	mov.w us,%d2	<---- unsigned short to unsigned is wrong
	clr.l ui
	mov.l ui,%d0
	mov.w %d2,%d0
	mov.l %d0,%d0
	.gdbline 0,14
L%1:
	.gdbend 2
	mov.l -4(%a6),%d2
	unlk %a6
	rts
	.gdbblock 2,1188
	comm s,2
	comm us,2
	comm i,4
	comm ui,4
.text 0
	.gdbend 0
	.gdbblock 0,1328
	.gdbend 1
	.gdbblock 1,1864
	.gdblinetab 0,2092