>
> -----Original Message-----
> From: gcc-patches-ow...@gcc.gnu.org [mailto:gcc-patches-ow...@gcc.gnu.org] On
> Behalf Of DJ Delorie
> Sent: Wednesday, November 02, 2011 11:24 PM
> To: gcc-patches@gcc.gnu.org
> Subject: expr.c: don't assume MUL for scaling pointers
>
>
> GCC assumes the target has a multiply insn, but better code is generated
> using shifts if it doesn't (vs a libcall). Found with the rl78-elf port.
>
> * expr.c (expand_expr_real_2): Don't try to emit a MUL-based
> expression if the target doesn't have a multiply pattern. Fall
> back to shifts instead of using libgcc calls.
Does this also work if the target has a multiply pattern but that is only
enabled some of the time (for example, depending on the specified -march=xyz
value)? What about the case where mul is available but much higher cost than
shift?
paul
