Hi!
On Thu, Oct 15, 2020 at 09:59:24AM +0100, Alex Coplan wrote:
> @@ -7650,20 +7650,27 @@ make_extraction (machine_mode mode, rtx inner,
> HOST_WIDE_INT pos,
> is_mode = GET_MODE (SUBREG_REG (inner));
> inner = SUBREG_REG (inner);
> }
> + else if ((GET_CODE (inner) == ASHIFT || GET_CODE (inner) == MULT)
> + && pos_rtx == 0 && pos == 0)
> + {
> + const HOST_WIDE_INT ci = INTVAL (XEXP (inner, 1));
> + const auto code = GET_CODE (inner);
> + const HOST_WIDE_INT shift_amt = (code == MULT) ? exact_log2 (ci) : ci;
Can you instead replace the mult by a shift somewhere earlier in
make_extract? That would make a lot more sense :-)
Segher
