🚀 go-pugleaf

I've just run across a rather annoying bug in Alcyon C v4.14 (the developer's
kit C):  it has a hard time with adding a word-sized integer constant to
a pointer variable.  My code originally looked something like

    STRUCTURE *this, *next;
    next = this + sizeof(STRUCTURE);  /* sizeof(STRUCTURE) = 8192 */

and it was generating code like:

    add.l #$80000000,R0

No difference whether I used "sizeof" or hardwired in the constant directly,
same bad results.  I eventually got around the problem by doing

    next = this; next++;


In another place, I was doing something similar:

    STRUCTURE *this, *next;
    int n;
    next = this + n*sizeof(STRUCTURE);

and instead of generating a multiply it generated a CLR.L instruction!

-Sandra Loosemore
sandra@cs.utah.edu, sandra@utah-cs.uucpu