The R8C has a 20-bit addressing mode for data outside its normal
addressing range. However, gcc *really* wants to CSE these and put
their addresses in registers, which is not going to work (pointers are
16 bit, these addresses are 20 bit). How can I force gcc to use [sym]
or [sym+reg] addressing, and not copy &sym to a register?
Alternately, can we fix the "gcc assumes all pointers are the same
size" assumption? Specifically this code hurts m32c:
rtx
memory_address (enum machine_mode mode, rtx x)
{
rtx oldx = x;
x = convert_memory_address (Pmode, x);
/* By passing constant addresses through registers
we get a chance to cse them. */
if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
x = force_reg (Pmode, x);
1. It discards the actual pointer mode and substitutes Pmode, whether
it's valid or not, and
2. It forces the address into a register whether it's valid or not.
