diff options
Diffstat (limited to 'lib/hipe/icode')
-rw-r--r-- | lib/hipe/icode/hipe_icode.erl | 17 | ||||
-rw-r--r-- | lib/hipe/icode/hipe_icode_ssa_const_prop.erl | 43 |
2 files changed, 42 insertions, 18 deletions
diff --git a/lib/hipe/icode/hipe_icode.erl b/lib/hipe/icode/hipe_icode.erl index 78508dff22..d2d08e0253 100644 --- a/lib/hipe/icode/hipe_icode.erl +++ b/lib/hipe/icode/hipe_icode.erl @@ -438,6 +438,7 @@ if_true_label/1, if_false_label/1, if_args/1, + if_args_update/2, if_pred/1, %% is_if/1, @@ -594,6 +595,7 @@ uses/1, defines/1, is_safe/1, + reduce_unused/1, strip_comments/1, subst/2, subst_uses/2, @@ -713,6 +715,9 @@ if_op_update(IF, NewOp) -> IF#icode_if{op=NewOp}. -spec if_args(#icode_if{}) -> [icode_term_arg()]. if_args(#icode_if{args=Args}) -> Args. +-spec if_args_update(#icode_if{}, [icode_term_arg()]) -> #icode_if{}. +if_args_update(IF, Args) -> IF#icode_if{args=Args}. + -spec if_true_label(#icode_if{}) -> icode_lbl(). if_true_label(#icode_if{true_label=TrueLbl}) -> TrueLbl. @@ -1765,6 +1770,18 @@ is_safe(Instr) -> #icode_end_try{} -> false end. +%% @doc Produces a simplified instruction sequence that is equivalent to [Instr] +%% under the assumption that all results of Instr are unused, or 'false' if +%% there is no such sequence (other than [Instr] itself). + +-spec reduce_unused(icode_instr()) -> false | [icode_instr()]. + +reduce_unused(Instr) -> + case is_safe(Instr) of + true -> []; + false -> false + end. + %%----------------------------------------------------------------------- -spec highest_var(icode_instrs()) -> non_neg_integer(). diff --git a/lib/hipe/icode/hipe_icode_ssa_const_prop.erl b/lib/hipe/icode/hipe_icode_ssa_const_prop.erl index 4ab4d7e95d..5d3d5413bc 100644 --- a/lib/hipe/icode/hipe_icode_ssa_const_prop.erl +++ b/lib/hipe/icode/hipe_icode_ssa_const_prop.erl @@ -97,11 +97,13 @@ visit_expression(Instruction, Environment) -> visit_begin_handler (Instruction, EvaluatedArguments, Environment); #icode_begin_try{} -> visit_begin_try (Instruction, EvaluatedArguments, Environment); - #icode_fail{} -> + #icode_fail{} -> visit_fail (Instruction, EvaluatedArguments, Environment); - _ -> - %% label, end_try, comment, return, - {[], [], Environment} + #icode_comment{} -> {[], [], Environment}; + #icode_end_try{} -> {[], [], Environment}; + #icode_enter{} -> {[], [], Environment}; + #icode_label{} -> {[], [], Environment}; + #icode_return{} -> {[], [], Environment} end. %%----------------------------------------------------------------------------- @@ -463,11 +465,15 @@ update_instruction(Instruction, Environment) -> update_type(Instruction, Environment); #icode_switch_tuple_arity{} -> update_switch_tuple_arity(Instruction, Environment); - _ -> - %% goto, comment, label, return, begin_handler, end_try, - %% begin_try, fail - %% We could but don't handle: catch?, fail? - [Instruction] + %% We could but don't handle: catch?, fail? + #icode_begin_handler{} -> [Instruction]; + #icode_begin_try{} -> [Instruction]; + #icode_comment{} -> [Instruction]; + #icode_end_try{} -> [Instruction]; + #icode_fail{} -> [Instruction]; + #icode_goto{} -> [Instruction]; + #icode_label{} -> [Instruction]; + #icode_return{} -> [Instruction] end. %%----------------------------------------------------------------------------- @@ -502,14 +508,12 @@ update_call(Instruction, Environment) -> [Instruction, NewInstructions]), NewInstructions end; -%% %% [] -> %% No destination; we don't touch this -%% [] -> -%% NewArguments = update_arguments(hipe_icode:call_args(Instruction), -%% Environment), -%% [hipe_icode:call_args_update(Instruction, NewArguments)]; + %% [] -> %% No destination; we don't touch this %% List-> %% Means register allocation; not implemented at this point _ -> - [Instruction] + NewArguments = update_arguments(hipe_icode:call_args(Instruction), + Environment), + [hipe_icode:call_args_update(Instruction, NewArguments)] end. %%----------------------------------------------------------------------------- @@ -574,7 +578,9 @@ update_if(Instruction, Environment) -> %% Convert the if-test to a type test if possible. Op = hipe_icode:if_op(Instruction), case Op =:= '=:=' orelse Op =:= '=/=' of - false -> [Instruction]; + false -> + [hipe_icode:if_args_update( + Instruction, update_arguments(Args, Environment))]; true -> [Arg1, Arg2] = Args, case EvaluatedArguments of @@ -604,8 +610,9 @@ conv_if_to_type(I, Const, Arg) when is_atom(Const); NewI = hipe_icode:mk_type([Arg], Test, T, F), ?CONST_PROP_MSG("if: ~w ---> type ~w\n", [I, NewI]), [NewI]; -conv_if_to_type(I, _, _) -> - [I]. +conv_if_to_type(I, Const, Arg) -> + %% Note: we are potentially commuting the (equality) comparison here + [hipe_icode:if_args_update(I, [Arg, hipe_icode:mk_const(Const)])]. %%----------------------------------------------------------------------------- |