Ian Lance Taylor <i...@google.com> wrote on 2010/04/25 20:07:03: > > Joakim Tjernlund <joakim.tjernl...@transmode.se> writes: > > > Noticed that gcc 4.3.4 doesn't optimize "add with carry" properly:
BTW, I can see in gcc src: (define_insn "" [(set (match_operand:CC 0 "cc_reg_operand" "=x,?y") (compare:CC (plus:SI (gt:SI (match_operand:SI 1 "gpc_reg_operand" "r,r") (const_int 0)) (match_operand:SI 2 "gpc_reg_operand" "r,r")) (const_int 0))) (clobber (match_scratch:SI 3 "=&r,&r"))] "TARGET_32BIT" "@ {a|addc} %3,%1,%1\;{sfe|subfe} %3,%1,%3\;{aze.|addze.} %3,%2 #" [(set_attr "type" "compare") (set_attr "length" "12,16")]) so there seems to be possible for gcc to emit them but how do I make gcc do that? Jocke