Added elimination of maps:is_key/2 calls to HiPE

 * Implemented removal of maps:is_key/2 calls of which the result is
   known in a new pass during the typed phase, called
   hipe_icode_call_elim.
 * Added the option icode_call_elim that enables the
   hipe_icode_call_elim pass, and made it default for o2.

2 files changed, 79 insertions, 1 deletions

diff --git a/lib/hipe/icode/Makefile b/lib/hipe/icode/Makefile
index a5edb10d90..c86562a981 100644
--- a/lib/hipe/icode/Makefile
+++ b/lib/hipe/icode/Makefile
@@ -59,7 +59,7 @@ DOC_MODULES = hipe_beam_to_icode \
 	hipe_icode_pp hipe_icode_primops \
 	hipe_icode_range \
 	hipe_icode_split_arith \
-	hipe_icode_ssa hipe_icode_ssa_const_prop \
+	hipe_icode_ssa hipe_icode_ssa_const_prop hipe_icode_call_elim \
 	hipe_icode_ssa_copy_prop hipe_icode_ssa_struct_reuse \
 	hipe_icode_type $(HIPE_MODULES)
 
diff --git a/lib/hipe/icode/hipe_icode_call_elim.erl b/lib/hipe/icode/hipe_icode_call_elim.erl
new file mode 100644
index 0000000000..6a22133962
--- /dev/null
+++ b/lib/hipe/icode/hipe_icode_call_elim.erl
@@ -0,0 +1,78 @@
+%% -*- erlang-indent-level: 2 -*-
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2016. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+%%----------------------------------------------------------------------
+%% File    : hipe_icode_call_elim.erl
+%% Authors : Daniel S. McCain <[email protected]>,
+%%           Magnus Lång <[email protected]>
+%% Created : 14 Apr 2014 by Magnus Lång <[email protected]>
+%% Purpose : Eliminate calls to BIFs that are side-effect free only when
+%%           executed on some argument types.
+%%----------------------------------------------------------------------
+-module(hipe_icode_call_elim).
+-export([cfg/1]).
+
+-include("hipe_icode.hrl").
+-include("../flow/cfg.hrl").
+
+-spec cfg(cfg()) -> cfg().
+
+cfg(IcodeSSA) ->
+  lists:foldl(fun (Lbl, CFG1) ->
+		  BB1 = hipe_icode_cfg:bb(CFG1, Lbl),
+		  Code1 = hipe_bb:code(BB1),
+		  Code2 = lists:map(fun elim_insn/1, Code1),
+		  BB2 = hipe_bb:code_update(BB1, Code2),
+		  hipe_icode_cfg:bb_add(CFG1, Lbl, BB2)
+	      end, IcodeSSA, hipe_icode_cfg:labels(IcodeSSA)).
+
+-spec elim_insn(icode_instr()) -> icode_instr().
+elim_insn(Insn=#icode_call{'fun'={_,_,_}=MFA, args=Args, type=remote,
+			   dstlist=[Dst=#icode_variable{
+				      annotation={type_anno, RetType, _}}]}) ->
+  Opaques = 'universe',
+  case erl_types:t_is_singleton(RetType, Opaques) of
+    true ->
+      ArgTypes = [case Arg of
+		    #icode_variable{annotation={type_anno, Type, _}} -> Type;
+		    #icode_const{} ->
+		      erl_types:t_from_term(hipe_icode:const_value(Arg))
+		  end || Arg <- Args],
+      case can_be_eliminated(MFA, ArgTypes) of
+	true ->
+	  Const = hipe_icode:mk_const(
+		    erl_types:t_singleton_to_term(RetType, Opaques)),
+	  #icode_move{dst=Dst, src=Const};
+	false -> Insn
+      end;
+    false -> Insn
+  end;
+elim_insn(Insn) -> Insn.
+
+
+%% A function can be eliminated for some argument types if it has no side
+%% effects when run on arguments of those types.
+
+-spec can_be_eliminated(mfa(), [erl_types:erl_type()]) -> boolean().
+
+can_be_eliminated({maps, is_key, 2}, [_K, M]) ->
+  erl_types:t_is_map(M);
+can_be_eliminated(_, _) ->
+  false.