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-rw-r--r--lib/hipe/rtl/hipe_tagscheme.erl49
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