diff options
| -rw-r--r-- | lib/hipe/rtl/hipe_rtl_lcm.erl | 40 |
1 files changed, 23 insertions, 17 deletions
diff --git a/lib/hipe/rtl/hipe_rtl_lcm.erl b/lib/hipe/rtl/hipe_rtl_lcm.erl index 9dcdd05fb1..b0ec86eef7 100644 --- a/lib/hipe/rtl/hipe_rtl_lcm.erl +++ b/lib/hipe/rtl/hipe_rtl_lcm.erl @@ -226,13 +226,12 @@ 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 +251,31 @@ 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 +310,8 @@ 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. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |