"Cannot generate reloads"

[Jack Dennon <jdennon at seasurf dot net>]

Attached text file is a gcc bug report.
Well, it could be a bug.

When compiled with the following script

#! /bin/bash
gcc -v -save-temps -g -O2 -c $1.c

this source file generates an error that can be eliminated
by removing the optimization (-O2):

/* code.c - actions for hoc7 */
/* #include "hoc.h"
   #include "hoc.tab.h"
 */

#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
/* #include "./drivers2_0/comdev2_0.h"
 */

typedef	union Datum {	/* interpreter stack type */
	double	val;
/*	Symbol	*sym; */
	char	*str;
} Datum;

extern Datum pop(void);

/*-------------------------------------------------------------*/
void leftstring(void)	/* b$ = lftstr(a$,nchar) */
{
	Datum d1, d2;
	char *mem;
	
	d2 = pop();	/* nchar */
	d1 = pop();	/* a$    */
	
	mem = (char *)malloc((int)d2.val+1);
	if (mem == NULL) {
		execerror("leftstring: malloc error",d1.str);
		return;
	}
	
	strncpy(mem,d1.str,(int)d2.val);
	d1.str = mem;
	push(d1);
}
/*-------------------------------------------------------------*/


The following was written to stderr:


Reading specs from /usr/lib/gcc-lib/i386-slackware-linux/2.95.3/specs
gcc version 2.95.3 20010315 (release)
 /usr/lib/gcc-lib/i386-slackware-linux/2.95.3/cpp0 -lang-c -v -D__GNUC__=2 -D__GNUC_MINOR__=95 -D__ELF__ -Dunix -D__i386__ -Dlinux -D__ELF__ -D__unix__ -D__i386__ -D__linux__ -D__unix -D__linux -Asystem(posix) -D__OPTIMIZE__ -g -Acpu(i386) -Amachine(i386) -Di386 -D__i386 -D__i386__ strcode.c strcode.i
GNU CPP version 2.95.3 20010315 (release) (i386 Linux/ELF)
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/lib/gcc-lib/i386-slackware-linux/2.95.3/include
 /usr/include
End of search list.
The following default directories have been omitted from the search path:
 /usr/lib/gcc-lib/i386-slackware-linux/2.95.3/../../../../include/g++-3
 /usr/lib/gcc-lib/i386-slackware-linux/2.95.3/../../../../i386-slackware-linux/include
End of omitted list.
 /usr/lib/gcc-lib/i386-slackware-linux/2.95.3/cc1 strcode.i -quiet -dumpbase strcode.c -g -O2 -version -o strcode.s
GNU C version 2.95.3 20010315 (release) (i386-slackware-linux) compiled by GNU C version 2.95.3 20010315 (release).
strcode.c: In function `leftstring':
strcode.c:39: Unable to generate reloads for:
(insn 29 27 31 (parallel[ 
            (set (reg:SI 4 %esi)
                (fix:SI (fix:DF (subreg:DF (reg/v:DI 3 %ebx) 0))))
            (clobber (mem:HI (plus:SI (reg:SI 6 %ebp)
                        (const_int -2 [0xfffffffe])) 0))
            (clobber (mem:HI (plus:SI (reg:SI 6 %ebp)
                        (const_int -4 [0xfffffffc])) 0))
            (clobber (mem:SI (plus:SI (reg:SI 6 %ebp)
                        (const_int -8 [0xfffffff8])) 0))
            (clobber (scratch:HI))
        ] ) 149 {fix_truncdfsi2+1} (insn_list 17 (nil))
    (expr_list:REG_DEAD (reg/v:DI 3 %ebx)
        (expr_list:REG_UNUSED (scratch:HI)
            (nil))))


---------------------------------------------------------------
The error goes away if I remove the optimization option -O2.

It appears  to have something to do with the pop() function,
and probably is something that I'm doing wrong. This is a portion
of my hoc7 version of Kernighan & Pike's hoc interpreter, being
built with Bison. Originally developed hoc7 on my GNU/linux 2.0,
then ported over to 2.2, then to 2.4. Problem turned up on the
last port. I can easily evade the problem by simply dropping
optimization, and it is doubtful that this is actually a bug.

Copy of my article on  hoc7  and sources for the entire project
are in the file   hoc7n.tgz  that can be downloaded from

	www.seasurf.com/~jdennon


Thank you.
jdennon@seasurf.com