diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/hipe/rtl/hipe_tagscheme.erl | 49 |
1 files changed, 32 insertions, 17 deletions
diff --git a/lib/hipe/rtl/hipe_tagscheme.erl b/lib/hipe/rtl/hipe_tagscheme.erl index 305aacb571..1d9861da7a 100644 --- a/lib/hipe/rtl/hipe_tagscheme.erl +++ b/lib/hipe/rtl/hipe_tagscheme.erl @@ -509,33 +509,48 @@ unsafe_fixnum_sub(Arg1, Arg2, Res) -> %%% (16X+tag)+((16Y+tag)-tag) = 16X+tag+16Y = 16(X+Y)+tag %%% (16X+tag)-((16Y+tag)-tag) = 16X+tag-16Y = 16(X-Y)+tag -fixnum_addsub(AluOp, Arg1, Arg2, Res, OtherLab) -> +fixnum_addsub(AluOp, Arg1, Arg2, FinalRes, OtherLab) -> NoOverflowLab = hipe_rtl:mk_new_label(), %% XXX: Consider moving this test to the users of fixnum_addsub. - case Arg1 =/= Res andalso Arg2 =/= Res of - true -> - %% Args differ from res. + {Res, Tail} = + case Arg1 =/= FinalRes andalso Arg2 =/= FinalRes of + true -> + %% Args differ from res. + {FinalRes, [NoOverflowLab]}; + false -> + %% At least one of the arguments is the same as Res. + Tmp = hipe_rtl:mk_new_reg_gcsafe(), + {Tmp, [NoOverflowLab, hipe_rtl:mk_move(FinalRes, Tmp)]} + end, + case (hipe_rtl:is_imm(Arg1) andalso AluOp =:= 'add') + orelse hipe_rtl:is_imm(Arg2) + of + true -> + %% Pre-compute the untagged immediate. The optimisers won't do this for us + %% since they don't know that the untag never underflows. + {Var, Imm0} = + case hipe_rtl:is_imm(Arg2) of + true -> {Arg1, Arg2}; + false -> {Arg2, Arg1} + end, + Imm = hipe_rtl:mk_imm(hipe_rtl:imm_value(Imm0) - ?TAG_IMMED1_SMALL), + [hipe_rtl:mk_alub(Res, Var, AluOp, Imm, not_overflow, + hipe_rtl:label_name(NoOverflowLab), + hipe_rtl:label_name(OtherLab), 0.99) + |Tail]; + false -> %% Commute add to save a move on x86 {UntagFirst, Lhs, Rhs} = case AluOp of 'add' -> {Arg1, Res, Arg2}; 'sub' -> {Arg2, Arg1, Res} end, - [hipe_rtl:mk_alu(Res, UntagFirst, sub, hipe_rtl:mk_imm(?TAG_IMMED1_SMALL)), + [hipe_rtl:mk_alu(Res, UntagFirst, sub, + hipe_rtl:mk_imm(?TAG_IMMED1_SMALL)), hipe_rtl:mk_alub(Res, Lhs, AluOp, Rhs, not_overflow, hipe_rtl:label_name(NoOverflowLab), - hipe_rtl:label_name(OtherLab), 0.99), - NoOverflowLab]; - false -> - %% At least one of the arguments is the same as Res. - Tmp = hipe_rtl:mk_new_reg_gcsafe(), - Tmp2 = hipe_rtl:mk_new_var(), % XXX: shouldn't this var be a reg? - [hipe_rtl:mk_alu(Tmp, Arg2, sub, hipe_rtl:mk_imm(?TAG_IMMED1_SMALL)), - hipe_rtl:mk_alub(Tmp2, Arg1, AluOp, Tmp, not_overflow, - hipe_rtl:label_name(NoOverflowLab), - hipe_rtl:label_name(OtherLab), 0.99), - NoOverflowLab, - hipe_rtl:mk_move(Res, Tmp2)] + hipe_rtl:label_name(OtherLab), 0.99) + |Tail] end. %%% ((16X+tag) div 16) * ((16Y+tag)-tag) + tag = X*16Y+tag = 16(XY)+tag |