On Mar 4, 2008, Kenneth Zadeck <[EMAIL PROTECTED]> wrote: > Richard Sandiford wrote: >> If we went for an explicit move, I assume we would either have to >> (a) discount hard regs that can't be moved, (b) force backends to >> allow all no-op moves or (c) circumvent the backend somehow.
> From my point of view, this is a killer argument that if we want to > build fuds/birthpoints for all regs, the info must be on the side. Nah. It can't be too hard to implicitly insert a (set (match_operand 0 "anything_goes_p" "X") (match_dup 0)) pattern in every back end, even behind the scenes. We might as well do this for USEs, CLOBBERs, ASMs (and DEBUG_INSNs), and phase out some of the special treatment they get at various places for not being recognizable. -- Alexandre Oliva http://www.lsd.ic.unicamp.br/~oliva/ FSF Latin America Board Member http://www.fsfla.org/ Red Hat Compiler Engineer [EMAIL PROTECTED], gcc.gnu.org} Free Software Evangelist [EMAIL PROTECTED], gnu.org}
