Re: bad register name `%sil'

[Kip Macy <kmacy@xxxxxxxxxxx>]

My first guess would be that that is a binutils issue. In other
words, the assembler might not be up to date with the compiler.

				-Kip

On Mon, 2 Feb 2004, YONETANI Tomokazu wrote:

> Hello.
> Is our gcc3 known to produce a bad code when '-O -march=pentium4'
> are specified? This is from buildkernel(sorry, very long lines):
>
> cc -c -O -pipe -march=pentium4 -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes  -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual  -fformat-extensions -ansi -g -nostdinc -I. -I/home/source/dragonfly/src/sys -I/home/source/dragonfly/src/sys/../include -I/home/source/dragonfly/src/sys/contrib/dev/acpica -I/home/source/dragonfly/src/sys/contrib/ipfilter  -D_KERNEL -include opt_global.h  -mpreferred-stack-boundary=2 -ffreestanding  /home/source/dragonfly/src/sys/vm/vm_pageout
.c
> {standard input}: Assembler messages:
> {standard input}:751: Error: bad register name `%sil'
> *** Error code 1
>
> It always fails at vm_pageout.c, and the code in question is in the
> function vm_pageout_flush(). If I replace '-O' with '-O2', the reference
> to `%sil' disappears from the assembly code.
>
> The following is minimum code example to reproduce this.
>
> $ CCVER=gcc3 cc -S -o a.s -O -pipe -march=pentium4 -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes  -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual  -fformat-extensions -ansi -g -D_KERNEL -mpreferred-stack-boundary=2 -ffreestanding  a.c
> $ cat ~/a.c
>
> #include <sys/param.h>
> #include <sys/systm.h>
>
> typedef struct {
> 	u_short flags, paging_in_progress;
> } *o_t;
>
> typedef struct {
> 	u_short flags;
> 	u_char busy;
> 	o_t object;
> } *p_t;
>
> void foo(o_t);
> void foo2(p_t);
> int baz(p_t *mc, int count, int flags);
>
> int
> baz(p_t *mc, int count, int flags)
> {
> 	o_t object;
> 	p_t mt;
> 	int i;
>
> 	for (i = 0; i < count; i++) {
> 		mt = mc[i];
> 		atomic_add_char(&mt->busy, 1);
> 		if (mt->flags) {
> 			foo2(mt);
> 			atomic_clear_short(&mt->flags, 0x10);
> 		}
> 	}
>
> 	object = mc[0]->object;
>
> 	for (i = 0; i < count; i++) {
> 		mt = mc[i];
> 		atomic_clear_short(&object->flags, 0x40);
> 		foo(object);
> 		atomic_subtract_char(&mt->busy, 1);
> 	}
> 	return 0;
> }
>