On Thu, 2005-08-25 at 21:24 -0700, Steve Zook wrote:
> Using m68k-elf-gcc with either revision 3.3.3 or 3.4.4, I compile the
> following test program (as a C++ program) at -O2 to an object file:
>
>
> struct sA { unsigned volatile const B;
> unsigned volatile C;
> unsigned const D;
> unsigned E; };
> void Function( sA & A ) { A.B; A.C; A.D; A.E; }
>
>
> The object file I get looks like (edited for brevity):
>
> .globl _Z8FunctionR2sA
> .type _Z8FunctionR2sA, @function
> _Z8FunctionR2sA:
> link.w %a6,#0
> move.l 8(%a6),%a0 | A, A
This is a load of A.B. It's the first member of the structure, and
thus, is at offset 0, and is also known as "A".
I imagine if you rearrange the struct so that B and C are farther into
the struct (IE add a dummy member in front, etc), you'd see the more
explicit loads you are looking for.
> move.l 4(%a0),%d0 | <variable>.C, <variable>.C
> unlk %a6
> rts
>
> I was expecting that A.B and A.C would both generate loads since they are
> both volatile, and that A.D and A.E would not, but only A.C loads.
>
> Have I misunderstood how volatile const should work, or is this a bug I
> should submit?
>
>
