On 04/20/2011 09:09 AM, Jakub Jelinek wrote:
> Hi!
>
> This splitter allows us to optimize (x {* {2,4,8},<< {1,2,3}}) {|,^} y
> for constant integer y <= {1ULL,3ULL,7ULL} using lea{l,q} (| or ^ in
> that case, when the low bits are known to be all 0, is like plus).
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2011-04-20 Jakub Jelinek <ja...@redhat.com>
>
> PR target/48688
> * config/i386/i386.md (*lea_general_4): New define_insn_and_split.
Any chance you could do this in combine instead? Shift-and-add patterns
are a fairly common architectural feature...
r~
