c/1570: gcc 2.8.1 has autoincrement bug

[rglan@engr.sgi.com]

>Number:         1570
>Category:       c
>Synopsis:       gcc 2.8.1 has autoincrement bug
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          wrong-code
>Submitter-Id:   net
>Arrival-Date:   Fri Jan 05 17:16:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Rob Glanville
>Release:        gcc 2.8.1
>Organization:
>Environment:
Irix64 release 6.5
>Description:
When useing an index into an array, and autoincrementing the index,
the compiler doesn't generate the code to autoincrement the index.

=============Code sample======================
#include <stdio.h>

unsigned long Point;
unsigned char buf[8];
unsigned char val;

int main(void) {
        Point = 0;
        buf[0] = 1;
        buf[1] = 0;
        buf[2] = 1;
        val = (buf[Point++] << 2) | (buf[Point++] << 1) | (buf[Point++]);
        printf("val = %x, Point = %x\n",val,Point);
        return(0);
        }
=============end of sample===================
produces an output of;
val=7, Point=1;
I understand that the expression isn't really legal since
it involves autoincrementing an index in a certain order
that isn't guarenteed by any compiler, but it should at
least increment the index pointer as it evaluates the
expression.
>How-To-Repeat:
Compile small source code. Run it. Output should be;

val=5, Point=3

where val is there bits ORed together and Point is the array index pointer
>Fix:
Make autoincrements work at all times.
>Release-Note:
>Audit-Trail:
>Unformatted: