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-rw-r--r--lib/hipe/rtl/hipe_rtl_lcm.erl107
1 files changed, 56 insertions, 51 deletions
diff --git a/lib/hipe/rtl/hipe_rtl_lcm.erl b/lib/hipe/rtl/hipe_rtl_lcm.erl
index 9dcdd05fb1..af39c9a0a4 100644
--- a/lib/hipe/rtl/hipe_rtl_lcm.erl
+++ b/lib/hipe/rtl/hipe_rtl_lcm.erl
@@ -182,42 +182,41 @@ delete_exprs(Code, _, _, []) ->
Code;
delete_exprs(Code, ExprMap, IdMap, [ExprId|Exprs]) ->
Expr = expr_id_map_get_expr(IdMap, ExprId),
- %% Perform a foldl that goes through the code and deletes all
- %% occurences of the expression.
- NewCode =
- lists:reverse
- (lists:foldl(fun(CodeExpr, Acc) ->
- case is_expr(CodeExpr) of
- true ->
- case expr_clear_dst(CodeExpr) =:= Expr of
- true ->
- pp_debug(" Deleting: ", []),
- pp_debug_instr(CodeExpr),
- %% Lookup expression entry.
- Defines =
- case expr_map_lookup(ExprMap, Expr) of
- {value, {_, _, Defs}} ->
- Defs;
- none ->
- exit({?MODULE, expr_map_lookup,
- "expression missing"})
- end,
- MoveCode =
- mk_expr_move_instr(hipe_rtl:defines(CodeExpr),
- Defines),
- pp_debug(" Replacing with: ", []),
- pp_debug_instr(MoveCode),
- [MoveCode|Acc];
- false ->
- [CodeExpr|Acc]
- end;
- false ->
- [CodeExpr|Acc]
- end
- end,
- [], Code)),
+ %% Lookup expression entry.
+ {value, {_, _, Defines}} = expr_map_lookup(ExprMap, Expr),
+ %% Go through the code and deletes all occurences of the expression.
+ NewCode = delete_expr(Code, Expr, Defines, []),
delete_exprs(NewCode, ExprMap, IdMap, Exprs).
+delete_expr([], _Expr, _Defines, Acc) -> lists:reverse(Acc);
+delete_expr([CodeExpr|Code], Expr, Defines, Acc) ->
+ case exp_kill_expr(CodeExpr, [Expr]) of
+ [] -> % Expr was killed; deleting stops here
+ pp_debug(" Stopping before: ", []),
+ pp_debug_instr(CodeExpr),
+ lists:reverse(Acc, [CodeExpr|Code]);
+ [Expr] ->
+ NewCodeExpr =
+ case is_expr(CodeExpr) of
+ true ->
+ case expr_clear_dst(CodeExpr) =:= Expr of
+ true ->
+ pp_debug(" Deleting: ", []),
+ pp_debug_instr(CodeExpr),
+ MoveCode = mk_expr_move_instr(hipe_rtl:defines(CodeExpr),
+ Defines),
+ pp_debug(" Replacing with: ", []),
+ pp_debug_instr(MoveCode),
+ MoveCode;
+ false ->
+ CodeExpr
+ end;
+ false ->
+ CodeExpr
+ end,
+ delete_expr(Code, Expr, Defines, [NewCodeExpr|Acc])
+ end.
+
%%=============================================================================
%% Goes through the given list of expressions and inserts them at
%% appropriate places in the code.
@@ -226,13 +225,12 @@ insert_exprs(CFG, _, _, _, _, BetweenMap, []) ->
insert_exprs(CFG, Pred, Succ, ExprMap, IdMap, BetweenMap, [ExprId|Exprs]) ->
Expr = expr_id_map_get_expr(IdMap, ExprId),
Instr = expr_map_get_instr(ExprMap, Expr),
- case hipe_rtl_cfg:succ(CFG, Pred) of
- [_] ->
+ case try_insert_expr_last(CFG, Pred, Instr) of
+ {ok, NewCFG} ->
pp_debug(" Inserted last: ", []),
pp_debug_instr(Instr),
- NewCFG = insert_expr_last(CFG, Pred, Instr),
insert_exprs(NewCFG, Pred, Succ, ExprMap, IdMap, BetweenMap, Exprs);
- _ ->
+ not_safe ->
case hipe_rtl_cfg:pred(CFG, Succ) of
[_] ->
pp_debug(" Inserted first: ", []),
@@ -252,25 +250,31 @@ insert_exprs(CFG, Pred, Succ, ExprMap, IdMap, BetweenMap, [ExprId|Exprs]) ->
%% Recursively goes through the code in a block and returns a new block
%% with the new code inserted second to last (assuming the last expression
%% is a branch operation).
-insert_expr_last(CFG0, Label, Instr) ->
- Code0 = hipe_bb:code(hipe_rtl_cfg:bb(CFG0, Label)),
- %% FIXME: Use hipe_bb:butlast() instead?
- Code1 = insert_expr_last_work(Label, Instr, Code0),
- hipe_rtl_cfg:bb_add(CFG0, Label, hipe_bb:mk_bb(Code1)).
+try_insert_expr_last(CFG0, Label, Instr) ->
+ case hipe_rtl_cfg:succ(CFG0, Label) of
+ [_] ->
+ Code0 = hipe_bb:code(hipe_rtl_cfg:bb(CFG0, Label)),
+ case insert_expr_last_work(Instr, Code0) of
+ not_safe -> not_safe;
+ Code1 ->
+ {ok, hipe_rtl_cfg:bb_add(CFG0, Label, hipe_bb:mk_bb(Code1))}
+ end;
+ _ -> not_safe
+ end.
%%=============================================================================
%% Recursively goes through the code in a block and returns a new block
%% with the new code inserted second to last (assuming the last expression
%% is a branch operation).
-insert_expr_last_work(_, Instr, []) ->
- %% This case should not happen since this means that block was completely
- %% empty when the function was called. For compatibility we insert it last.
- [Instr];
-insert_expr_last_work(_, Instr, [Code1]) ->
+insert_expr_last_work(_Instr, [#call{}]) ->
+ %% Call instructions clobber all expressions; we musn't insert the expression
+ %% before it
+ not_safe;
+insert_expr_last_work(Instr, [Code1]) ->
%% We insert the code next to last.
[Instr, Code1];
-insert_expr_last_work(Label, Instr, [Code|Codes]) ->
- [Code|insert_expr_last_work(Label, Instr, Codes)].
+insert_expr_last_work(Instr, [Code|Codes]) ->
+ [Code|insert_expr_last_work(Instr, Codes)].
%%=============================================================================
%% Inserts expression first in the block for the given label.
@@ -305,7 +309,8 @@ insert_expr_between(CFG0, BetweenMap, Pred, Succ, Instr) ->
{value, Label} ->
pp_debug(" Using existing new bb for edge (~w,~w) with label ~w~n",
[Pred, Succ, Label]),
- {insert_expr_last(CFG0, Label, Instr), BetweenMap}
+ {ok, NewCfg} = try_insert_expr_last(CFG0, Label, Instr),
+ {NewCfg, BetweenMap}
end.
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