> I emit (clobber (reg:CC CCreg)) with every instruction that can set > condition codes, but it appears that nearly all of them are removed before > we reach reorg where mark_referenced_resources() or mark_set_resources() > would detect a conflict of the CCreg's.
Clobbers shouldn't be removed if they are needed for an insn to match so... > The define_expand pattern for add looks like > > (define_expand "add<S:mode>3" > [(set (match_operand:S 0 "nonimmediate_operand") > (plus:S (match_operand:S 1 "general_operand") > (match_operand:S 2 "general_operand"))) > (clobber (reg:CC CC_REGNUM))] > "" > ..... > }) > has corresponding define_insn's are > > > (define_insn "*addsi" > [(set (match_operand:SI 0 "nonimmediate_operand" "=rm,rm,rS,rm") > (plus:SI (match_operand:SI 1 "nonimmediate_operand" "%0, 0, 0,rm") > (match_operand:SI 2 "general_operand" "QI, K,i,rm")))] ,........ > ) ... why is there no clobber in the pattern if the instruction clobbers CC? -- Eric Botcazou
