On Fri, Apr 07, 2017 at 04:34:44PM +0200, Ulrich Weigand wrote: > > +; Peephole to combine a load-and-test from volatile memory which combine > > does > > +; not do. > > +(define_peephole2 > > + [(set (match_operand:GPR 0 "register_operand") > > + (match_operand:GPR 2 "memory_operand")) > > + (set (reg CC_REGNUM) > > + (compare (match_dup 0) (match_operand:GPR 1 "const0_operand")))] > > + "s390_match_ccmode(insn, CCSmode) && TARGET_EXTIMM > > + && GENERAL_REG_P (operands[0]) > > + && satisfies_constraint_T (operands[2])" > > + [(parallel > > + [(set (reg:CCS CC_REGNUM) > > + (compare:CCS (match_dup 2) (match_dup 1))) > > + (set (match_dup 0) (match_dup 2))])]) > > Still wondering why this is necessary.
It's necessary vecause Combine refuses to match anything that contains a volatile memory reference, using a global flag for Recog. > > @@ -6518,13 +6533,30 @@ > > [(parallel > > [(set (match_operand:SI 0 "register_operand" "") > > (match_operator:SI 1 "s390_eqne_operator" > > - [(match_operand:CCZ1 2 "register_operand") > > + [(match_operand 2 "cc_reg_operand") > > (match_operand 3 "const0_operand")])) > > (clobber (reg:CC CC_REGNUM))])] > > "" > > - "emit_insn (gen_sne (operands[0], operands[2])); > > - if (GET_CODE (operands[1]) == EQ) > > - emit_insn (gen_xorsi3 (operands[0], operands[0], const1_rtx)); > > + "machine_mode mode = GET_MODE (operands[2]); > > + if (TARGET_Z196) > > + { > > + rtx cond, ite; > > + > > + if (GET_CODE (operands[1]) == NE) > > + cond = gen_rtx_NE (VOIDmode, operands[2], const0_rtx); > > + else > > + cond = gen_rtx_EQ (VOIDmode, operands[2], const0_rtx); > > + ite = gen_rtx_IF_THEN_ELSE (SImode, cond, const1_rtx, const0_rtx); > > + emit_insn (gen_rtx_SET (operands[0], ite)); > > + } > > + else > > + { > > + if (mode != CCZ1mode) > > + FAIL; > > + emit_insn (gen_sne (operands[0], operands[2])); > > + if (GET_CODE (operands[1]) == EQ) > > + emit_insn (gen_xorsi3 (operands[0], operands[0], const1_rtx)); > > + } > > DONE;") > > >From what I can see in the rest of the patch, none of the CS changes now > actually *rely* on this change to cstorecc4 ... s390_expand_cs_tdsi only > calls cstorecc4 on !TARGET_Z196, where the above change is a no-op, and > in the TARGET_Z196 case it deliberates does *not* use cstorecc4. You're right. After all the refactoring, this part of the patch has become unused. > Now, in general this improvement to cstorecc4 is of course valuable > in itself. But I think at this point it might be better to separate > this out into an independent patch (and measure its effect separately). Ciao Dominik ^_^ ^_^ -- Dominik Vogt IBM Germany