Merge branch 'bjorn/compiler/maps'

* bjorn/compiler/maps:
  v3_codegen: Teach the put_map_* instructions to reuse source registers
  beam_validator: Tighten tests of maps
  v3_core: Eliminate the sloppiness-encouraging get_ianno/1 function
  v3_core: Add is_map tests before map instructions
  beam_type: Use the complete register map when calculating liveness
  Introduce '%live' annotations with a complete register map
  beam_validator: Teach bif_type/3 and is_bif_safe/2 about is_map/1
  v3_core: Simplify conversion of map patterns

12 files changed, 138 insertions, 149 deletions

diff --git a/lib/compiler/src/beam_a.erl b/lib/compiler/src/beam_a.erl
index fe4f473846..dd7e03dd28 100644
--- a/lib/compiler/src/beam_a.erl
+++ b/lib/compiler/src/beam_a.erl
@@ -54,6 +54,9 @@ rename_instrs([{call_only,A,F}|Is]) ->
     [{call,A,F},return|rename_instrs(Is)];
 rename_instrs([{call_ext_only,A,F}|Is]) ->
     [{call_ext,A,F},return|rename_instrs(Is)];
+rename_instrs([{'%live',_}|Is]) ->
+    %% When compiling from old .S files.
+    rename_instrs(Is);
 rename_instrs([I|Is]) ->
     [rename_instr(I)|rename_instrs(Is)];
 rename_instrs([]) -> [].
diff --git a/lib/compiler/src/beam_block.erl b/lib/compiler/src/beam_block.erl
index 7d65dc983a..92f09e400c 100644
--- a/lib/compiler/src/beam_block.erl
+++ b/lib/compiler/src/beam_block.erl
@@ -184,7 +184,7 @@ embed_lines([], Acc) -> Acc.
 
 opt_blocks([{block,Bl0}|Is]) ->
     %% The live annotation at the beginning is not useful.
-    [{'%live',_}|Bl] = Bl0,
+    [{'%live',_,_}|Bl] = Bl0,
     [{block,opt_block(Bl)}|opt_blocks(Is)];
 opt_blocks([I|Is]) ->
     [I|opt_blocks(Is)];
@@ -269,7 +269,7 @@ opt([{set,_,_,{line,_}}=Line1,
 opt([{set,Ds0,Ss,Op}|Is0]) ->	
     {Ds,Is} = opt_moves(Ds0, Is0),
     [{set,Ds,Ss,Op}|opt(Is)];
-opt([{'%live',_}=I|Is]) ->
+opt([{'%live',_,_}=I|Is]) ->
     [I|opt(Is)];
 opt([]) -> [].
 
diff --git a/lib/compiler/src/beam_type.erl b/lib/compiler/src/beam_type.erl
index d9713cef0d..26c933481a 100644
--- a/lib/compiler/src/beam_type.erl
+++ b/lib/compiler/src/beam_type.erl
@@ -244,7 +244,7 @@ clearerror([], OrigIs) -> [{set,[],[],fclearerror}|OrigIs].
 %%  Combine two blocks and eliminate any move instructions that assign
 %%  to registers that are killed later in the block.
 %%
-merge_blocks(B1, [{'%live',_}|B2]) ->
+merge_blocks(B1, [{'%live',_,_}|B2]) ->
     merge_blocks_1(B1++[{set,[],[],stop_here}|B2]).
 
 merge_blocks_1([{set,[],_,stop_here}|Is]) -> Is;
@@ -329,27 +329,27 @@ build_alloc(Words, Floats) -> {alloc,[{words,Words},{floats,Floats}]}.
 
 %% flt_liveness([Instruction]) -> [Instruction]
 %%  (Re)calculate the number of live registers for each heap allocation
-%%  function. We base liveness of the number of live registers at
-%%  entry to the instruction sequence.
+%%  function. We base liveness of the number of register map at the
+%%  beginning of the instruction sequence.
 %%
 %%  A 'not_possible' term will be thrown if the set of live registers
 %%  is not continous at an allocation function (e.g. if {x,0} and {x,2}
 %%  are live, but not {x,1}).
 
-flt_liveness([{'%live',Live}=LiveInstr|Is]) ->
-    flt_liveness_1(Is, init_regs(Live), [LiveInstr]).
+flt_liveness([{'%live',_Live,Regs}=LiveInstr|Is]) ->
+    flt_liveness_1(Is, Regs, [LiveInstr]).
 
-flt_liveness_1([{set,Ds,Ss,{alloc,_,Alloc}}|Is], Regs0, Acc) ->
-    Live = live_regs(Regs0),
+flt_liveness_1([{set,Ds,Ss,{alloc,Live0,Alloc}}|Is], Regs0, Acc) ->
+    Live = min(Live0, live_regs(Regs0)),
     I = {set,Ds,Ss,{alloc,Live,Alloc}},
-    Regs = foldl(fun(R, A) -> set_live(R, A) end, Regs0, Ds),
+    Regs1 = init_regs(Live),
+    Regs = x_live(Ds, Regs1),
     flt_liveness_1(Is, Regs, [I|Acc]);
 flt_liveness_1([{set,Ds,_,_}=I|Is], Regs0, Acc) ->
-    Regs = foldl(fun(R, A) -> set_live(R, A) end, Regs0, Ds),
+    Regs = x_live(Ds, Regs0),
     flt_liveness_1(Is, Regs, [I|Acc]);
-flt_liveness_1([{'%live',_}=I|Is], Regs, Acc) ->
-    flt_liveness_1(Is, Regs, [I|Acc]);
-flt_liveness_1([], _Regs, Acc) -> reverse(Acc).
+flt_liveness_1([{'%live',_,_}], _Regs, Acc) ->
+    reverse(Acc).
 
 init_regs(Live) ->
     (1 bsl Live) - 1.
@@ -364,14 +364,15 @@ live_regs_1(R, N) ->
 	1 -> live_regs_1(R bsr 1, N+1)
     end.
 
-set_live({x,X}, Regs) -> Regs bor (1 bsl X);
-set_live(_, Regs) -> Regs.
+x_live([{x,N}|Rs], Regs) -> x_live(Rs, Regs bor (1 bsl N));
+x_live([_|Rs], Regs) -> x_live(Rs, Regs);
+x_live([], Regs) -> Regs.
 
 %% update(Instruction, TypeDb) -> NewTypeDb
 %%  Update the type database to account for executing an instruction.
 %%
 %%  First the cases for instructions inside basic blocks.
-update({'%live',_}, Ts) -> Ts;
+update({'%live',_,_}, Ts) -> Ts;
 update({set,[D],[S],move}, Ts) ->
     tdb_copy(S, D, Ts);
 update({set,[D],[{integer,I},Reg],{bif,element,_}}, Ts0) ->
diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl
index 3249024854..7704690f86 100644
--- a/lib/compiler/src/beam_utils.erl
+++ b/lib/compiler/src/beam_utils.erl
@@ -196,7 +196,7 @@ is_pure_test({test,Op,_,Ops}) ->
 %%  Go through the instruction sequence in reverse execution
 %%  order, keep track of liveness and remove 'move' instructions
 %%  whose destination is a register that will not be used.
-%%  Also insert {'%live',Live} annotations at the beginning
+%%  Also insert {'%live',Live,Regs} annotations at the beginning
 %%  and end of each block.
 %%
 live_opt(Is0) ->
@@ -217,7 +217,7 @@ delete_live_annos([{block,Bl0}|Is]) ->
 	[] -> delete_live_annos(Is);
 	[_|_]=Bl -> [{block,Bl}|delete_live_annos(Is)]
     end;
-delete_live_annos([{'%live',_}|Is]) ->
+delete_live_annos([{'%live',_,_}|Is]) ->
     delete_live_annos(Is);
 delete_live_annos([I|Is]) ->
     [I|delete_live_annos(Is)];
@@ -366,11 +366,6 @@ check_liveness(R, [{apply,Args}|Is], St) ->
 	{x,_} -> {killed,St};
 	{y,_} -> check_liveness(R, Is, St)
     end;
-check_liveness({x,R}, [{'%live',Live}|Is], St) ->
-    if
-	R < Live -> check_liveness(R, Is, St);
-	true -> {killed,St}
-    end;
 check_liveness(R, [{bif,Op,{f,Fail},Ss,D}|Is], St0) ->
     case check_liveness_fail(R, Op, Ss, Fail, St0) of
 	{killed,St} = Killed ->
@@ -554,7 +549,7 @@ check_killed_block(R, [{set,Ds,Ss,_Op}|Is]) ->
 		false -> check_killed_block(R, Is)
 	    end
     end;
-check_killed_block(R, [{'%live',Live}|Is]) ->
+check_killed_block(R, [{'%live',Live,_}|Is]) ->
     case R of
 	{x,X} when X >= Live -> killed;
 	_ -> check_killed_block(R, Is)
@@ -577,7 +572,7 @@ check_used_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], St) ->
     end;
 check_used_block(R, [{set,Ds,Ss,Op}|Is], St) ->
     check_used_block_1(R, Ss, Ds, Op, Is, St);
-check_used_block(R, [{'%live',Live}|Is], St) ->
+check_used_block(R, [{'%live',Live,_}|Is], St) ->
     case R of
 	{x,X} when X >= Live -> {killed,St};
 	_ -> check_used_block(R, Is, St)
@@ -678,9 +673,9 @@ live_opt([{test,bs_start_match2,Fail,Live,[Src,_],_}=I|Is], _, D, Acc) ->
 
 %% Other instructions.
 live_opt([{block,Bl0}|Is], Regs0, D, Acc) ->
-    Live0 = {'%live',live_regs(Regs0)},
+    Live0 = {'%live',live_regs(Regs0),Regs0},
     {Bl,Regs} = live_opt_block(reverse(Bl0), Regs0, D, [Live0]),
-    Live = {'%live',live_regs(Regs)},
+    Live = {'%live',live_regs(Regs),Regs},
     live_opt(Is, Regs, D, [{block,[Live|Bl]}|Acc]);
 live_opt([{label,L}=I|Is], Regs, D0, Acc) ->
     D = gb_trees:insert(L, Regs, D0),
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index e60184c929..4d4536b79c 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -361,9 +361,6 @@ valfun_1({recv_mark,{f,Fail}}, Vst) when is_integer(Fail) ->
 valfun_1({recv_set,{f,Fail}}, Vst) when is_integer(Fail) ->
     Vst;
 %% Misc.
-valfun_1({'%live',Live}, Vst) ->
-    verify_live(Live, Vst),
-    Vst;
 valfun_1(remove_message, Vst) ->
     Vst;
 valfun_1({'%',_}, Vst) ->
@@ -669,9 +666,17 @@ valfun_4({test,test_arity,{f,Lbl},[Tuple,Sz]}, Vst) when is_integer(Sz) ->
     assert_type(tuple, Tuple, Vst),
     set_type_reg({tuple,Sz}, Tuple, branch_state(Lbl, Vst));
 valfun_4({test,has_map_fields,{f,Lbl},Src,{list,List}}, Vst) ->
-    validate_src([Src], Vst),
+    assert_type(map, Src, Vst),
     assert_strict_literal_termorder(List),
     branch_state(Lbl, Vst);
+valfun_4({test,is_map,{f,Lbl},[Src]}, Vst0) ->
+    Vst = branch_state(Lbl, Vst0),
+    case Src of
+	{Tag,_} when Tag =:= x; Tag =:= y ->
+	    set_type_reg(map, Src, Vst);
+	_ ->
+	    Vst
+    end;
 valfun_4({test,_Op,{f,Lbl},Src}, Vst) ->
     validate_src(Src, Vst),
     branch_state(Lbl, Vst);
@@ -766,7 +771,7 @@ valfun_4(_, _) ->
     error(unknown_instruction).
 
 verify_get_map(Fail, Src, List, Vst0) ->
-    assert_term(Src, Vst0),
+    assert_type(map, Src, Vst0),
     Vst1 = branch_state(Fail, Vst0),
     Keys = extract_map_keys(List),
     assert_strict_literal_termorder(Keys),
@@ -782,14 +787,14 @@ verify_get_map_pair([Src,Dst|Vs],Vst0,Vsti) ->
     verify_get_map_pair(Vs,Vst0,set_type_reg(term,Dst,Vsti)).
 
 verify_put_map(Fail, Src, Dst, Live, List, Vst0) ->
+    assert_type(map, Src, Vst0),
     verify_live(Live, Vst0),
     verify_y_init(Vst0),
     foreach(fun (Term) -> assert_term(Term, Vst0) end, List),
-    assert_term(Src, Vst0),
     Vst1 = heap_alloc(0, Vst0),
     Vst2 = branch_state(Fail, Vst1),
     Vst = prune_x_regs(Live, Vst2),
-    set_type_reg(term, Dst, Vst).
+    set_type_reg(map, Dst, Vst).
 
 %%
 %% Common code for validating bs_get* instructions.
@@ -1223,7 +1228,8 @@ assert_term(Src, Vst) ->
 %%
 %% number		Integer or Float of unknown value
 %%
-
+%% map			Map.
+%%
 
 assert_type(WantedType, Term, Vst) ->
     assert_type(WantedType, get_term_type(Term, Vst)).
@@ -1305,6 +1311,7 @@ get_term_type_1(nil=T, _) -> T;
 get_term_type_1({atom,A}=T, _) when is_atom(A) -> T;
 get_term_type_1({float,F}=T, _) when is_float(F) -> T;
 get_term_type_1({integer,I}=T, _) when is_integer(I) -> T;
+get_term_type_1({literal,Map}, _) when is_map(Map) -> map;
 get_term_type_1({literal,_}=T, _) -> T;
 get_term_type_1({x,X}=Reg, #vst{current=#st{x=Xs}}) when is_integer(X) ->
     case gb_trees:lookup(X, Xs) of
@@ -1554,6 +1561,7 @@ bif_type(is_float, [_], _) -> bool;
 bif_type(is_function, [_], _) -> bool;
 bif_type(is_integer, [_], _) -> bool;
 bif_type(is_list, [_], _) -> bool;
+bif_type(is_map, [_], _) -> bool;
 bif_type(is_number, [_], _) -> bool;
 bif_type(is_pid, [_], _) -> bool;
 bif_type(is_port, [_], _) -> bool;
@@ -1583,6 +1591,7 @@ is_bif_safe(is_float, 1) -> true;
 is_bif_safe(is_function, 1) -> true;
 is_bif_safe(is_integer, 1) -> true;
 is_bif_safe(is_list, 1) -> true;
+is_bif_safe(is_map, 1) -> true;
 is_bif_safe(is_number, 1) -> true;
 is_bif_safe(is_pid, 1) -> true;
 is_bif_safe(is_port, 1) -> true;
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl
index 2618f7adba..ea1959d0f8 100644
--- a/lib/compiler/src/sys_core_fold.erl
+++ b/lib/compiler/src/sys_core_fold.erl
@@ -1603,6 +1603,7 @@ eval_case(#c_case{arg=E,clauses=[#c_clause{pats=Ps0,
 	    %% is correct, the clause will always match at run-time.
 	    Case;
 	{true,Bs} ->
+	    eval_case_warn(B),
 	    {Ps,As} = unzip(Bs),
 	    InnerLet = cerl:c_let(Ps, core_lib:make_values(As), B),
 	    Let = cerl:c_let(Vs, E, InnerLet),
@@ -1610,6 +1611,19 @@ eval_case(#c_case{arg=E,clauses=[#c_clause{pats=Ps0,
     end;
 eval_case(Case, _) -> Case.
 
+eval_case_warn(#c_primop{anno=Anno,
+			 name=#c_literal{val=match_fail},
+			 args=[#c_literal{val=Reason}]}=Core)
+  when is_atom(Reason) ->
+    case member(eval_failure, Anno) of
+	false ->
+	    ok;
+	true ->
+	    %% Example: M = not_map, M#{k:=v}
+	    add_warning(Core, {eval_failure,Reason})
+    end;
+eval_case_warn(_) -> ok.
+
 %% case_opt(CaseArg, [Clause]) -> {CaseArg,[Clause]}.
 %%  Try and optimise a case by avoid building tuples or lists
 %%  in the case expression. Instead combine the variable parts
diff --git a/lib/compiler/src/v3_codegen.erl b/lib/compiler/src/v3_codegen.erl
index 8c1a0c08ac..cbe50b93b0 100644
--- a/lib/compiler/src/v3_codegen.erl
+++ b/lib/compiler/src/v3_codegen.erl
@@ -1523,9 +1523,11 @@ set_cg([{var,R}], {map,Op,Map,[{map_pair,{var,_}=K,V}]}, Le, Vdb, Bef,
     List = [cg_reg_arg(K,Int0),cg_reg_arg(V,Int0)],
 
     Live = max_reg(Bef#sr.reg),
-    Int1 = Int0#sr{reg=put_reg(R, Int0#sr.reg)},
-    Aft = clear_dead(Int1, Le#l.i, Vdb),
-    Target = fetch_reg(R, Int1#sr.reg),
+
+    %% The target register can reuse one of the source registers.
+    Aft0 = clear_dead(Int0, Le#l.i, Vdb),
+    Aft = Aft0#sr{reg=put_reg(R, Aft0#sr.reg)},
+    Target = fetch_reg(R, Aft#sr.reg),
 
     I = case Op of
 	assoc -> put_map_assoc;
@@ -1557,9 +1559,11 @@ set_cg([{var,R}], {map,Op,Map,Es}, Le, Vdb, Bef,
     List = flatmap(fun({K,V}) -> [K,cg_reg_arg(V,Int0)] end, Pairs),
 
     Live = max_reg(Bef#sr.reg),
-    Int1 = Int0#sr{reg=put_reg(R, Int0#sr.reg)},
-    Aft = clear_dead(Int1, Le#l.i, Vdb),
-    Target = fetch_reg(R, Int1#sr.reg),
+
+    %% The target register can reuse one of the source registers.
+    Aft0 = clear_dead(Int0, Le#l.i, Vdb),
+    Aft = Aft0#sr{reg=put_reg(R, Aft0#sr.reg)},
+    Target = fetch_reg(R, Aft#sr.reg),
 
     I = case Op of
 	assoc -> put_map_assoc;
diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl
index 9dd6b319a3..3c19a209c0 100644
--- a/lib/compiler/src/v3_core.erl
+++ b/lib/compiler/src/v3_core.erl
@@ -758,30 +758,28 @@ make_bool_switch_guard(L, E, V, T, F) ->
       {clause,NegL,[V],[],[V]}
      ]}.
 
-expr_map(M0,Es0,A,St0) ->
-    {M1,Mps,St1} = safe(M0, St0),
+expr_map(M0, Es0, A, St0) ->
+    {M1,Eps0,St1} = safe(M0, St0),
     case is_valid_map_src(M1) of
 	true ->
-	    case {M1,Es0} of
-		{#c_var{}, []} ->
-		    %% transform M#{} to is_map(M)
-		    {Vpat,St2} = new_var(St1),
-		    {Fpat,St3} = new_var(St2),
-		    Cs = [#iclause{
-			   anno=A,
-			   pats=[Vpat],
-			   guard=[#icall{anno=#a{anno=A},
+	    {M2,Eps1,St2} = map_build_pairs(M1, Es0, A, St1),
+	    M3 = case Es0 of
+		     [] -> M1;
+		     [_|_] -> M2
+		 end,
+	    Cs = [#iclause{
+		     anno=#a{anno=[compiler_generated|A]},
+		     pats=[],
+		     guard=[#icall{anno=#a{anno=A},
 				   module=#c_literal{anno=A,val=erlang},
 			           name=#c_literal{anno=A,val=is_map},
-				   args=[Vpat]}],
-			   body=[Vpat]}],
-		    Fc = fail_clause([Fpat], A, #c_literal{val=badarg}),
-		    {#icase{anno=#a{anno=A},args=[M1],clauses=Cs,fc=Fc},Mps,St3};
-		{_,_} ->
-		    {M2,Eps,St2} = map_build_pairs(M1, Es0, A, St1),
-		    {M2,Mps++Eps,St2}
-	    end;
-	false -> throw({bad_map,bad_map})
+				   args=[M1]}],
+		     body=[M3]}],
+	    Fc = fail_clause([], [eval_failure|A], #c_literal{val=badarg}),
+	    Eps = Eps0 ++ Eps1,
+	    {#icase{anno=#a{anno=A},args=[],clauses=Cs,fc=Fc},Eps,St2};
+	false ->
+	    throw({bad_map,bad_map})
     end.
 
 map_build_pairs(Map, Es0, Ann, St0) ->
@@ -1623,49 +1621,30 @@ pattern_map_pairs(Ps, St) ->
 		{CMapPair,EpsP,Sti1} = pattern_map_pair(P,Sti0),
 		{CMapPair, {EpsM++EpsP,Sti1}}
 	end, {[],St}, Ps),
-    {pat_alias_map_pairs(CMapPairs,[]),Eps,St1}.
-
-%% remove cluddering annotations
-pattern_map_clean_key(#c_literal{val=V}) -> {literal,V};
-pattern_map_clean_key(#c_var{name=V}) -> {var,V}.
-
-pat_alias_map_pairs(Ps1,Ps2) ->
-    Ps = Ps1 ++ Ps2,
-    F = fun(#c_map_pair{key=Ck,val=Cv},Dbi) ->
-		K = pattern_map_clean_key(Ck),
-		case dict:find(K,Dbi) of
-		    {ok,Cvs} -> dict:store(K,[Cv|Cvs],Dbi);
-		    _        -> dict:store(K,[Cv],Dbi)
-		end
-	end,
-    Kdb = lists:foldl(F,dict:new(),Ps),
-    pat_alias_map_pairs(Ps,Kdb,sets:new()).
-
-pat_alias_map_pairs([],_,_) -> [];
-pat_alias_map_pairs([#c_map_pair{key=Ck}=Pair|Pairs],Kdb,Set) ->
-    K = pattern_map_clean_key(Ck),
-    case sets:is_element(K,Set) of
-	true ->
-	    pat_alias_map_pairs(Pairs,Kdb,Set);
-	false ->
-	    Cvs = dict:fetch(K,Kdb),
-	    Cv = pat_alias_map_pair_values(Cvs),
-	    Set1 = sets:add_element(K,Set),
-	    [Pair#c_map_pair{val=Cv}|pat_alias_map_pairs(Pairs,Kdb,Set1)]
-    end.
-
-pat_alias_map_pair_values([Cv]) -> Cv;
-pat_alias_map_pair_values([Cv1,Cv2|Cvs]) ->
-    pat_alias_map_pair_values([pat_alias(Cv1,Cv2)|Cvs]).
+    {pat_alias_map_pairs(CMapPairs),Eps,St1}.
 
 pattern_map_pair({map_field_exact,L,K,V}, St0) ->
-    {Ck,EpsK,St1} = safe_pattern_expr(K,St0),
+    {Ck,EpsK,St1} = safe_pattern_expr(K, St0),
     {Cv,EpsV,St2} = pattern(V, St1),
-    {#c_map_pair{anno=lineno_anno(L,St2),
+    {#c_map_pair{anno=lineno_anno(L, St2),
 		 op=#c_literal{val=exact},
 		 key=Ck,
 		 val=Cv},EpsK++EpsV,St2}.
 
+pat_alias_map_pairs(Ps) ->
+    D = foldl(fun(#c_map_pair{key=K0}=Pair, D0) ->
+		      K = cerl:set_ann(K0, []),
+		      dict:append(K, Pair, D0)
+	      end, dict:new(), Ps),
+    pat_alias_map_pairs_1(dict:to_list(D)).
+
+pat_alias_map_pairs_1([{_,[#c_map_pair{val=V0}=Pair|Vs]}|T]) ->
+    V = foldl(fun(#c_map_pair{val=V}, Pat) ->
+		      pat_alias(V, Pat)
+	      end, V0, Vs),
+    [Pair#c_map_pair{val=V}|pat_alias_map_pairs_1(T)];
+pat_alias_map_pairs_1([]) -> [].
+
 %% pat_bin([BinElement], State) -> [BinSeg].
 
 pat_bin(Ps, St) -> [pat_segment(P, St) || P <- Ps].
@@ -1707,7 +1686,7 @@ pat_alias(#c_tuple{anno=Anno,es=Es1}, #c_tuple{es=Es2}) ->
 %% alias maps
 %% There are no literals in maps patterns (patterns are always abstract)
 pat_alias(#c_map{es=Es1}=M,#c_map{es=Es2}) ->
-    M#c_map{es=pat_alias_map_pairs(Es1,Es2)};
+    M#c_map{es=pat_alias_map_pairs(Es1++Es2)};
 
 pat_alias(#c_alias{var=V1,pat=P1},
 	  #c_alias{var=V2,pat=P2}) ->
@@ -1819,7 +1798,7 @@ uclauses(Lcs, Ks, St0) ->
 
 uclause(Cl0, Ks, St0) ->
     {Cl1,_Pvs,Used,New,St1} = uclause(Cl0, Ks, Ks, St0),
-    A0 = get_ianno(Cl1),
+    A0 = get_anno(Cl1),
     A = A0#a{us=Used,ns=New},
     {Cl1#iclause{anno=A},St1}.
 
@@ -2006,7 +1985,7 @@ ufun_clauses(Lcs, Ks, St0) ->
 
 ufun_clause(Cl0, Ks, St0) ->
     {Cl1,Pvs,Used,_,St1} = uclause(Cl0, [], Ks, St0),
-    A0 = get_ianno(Cl1),
+    A0 = get_anno(Cl1),
     A = A0#a{us=subtract(intersection(Used, Ks), Pvs),ns=[]},
     {Cl1#iclause{anno=A},St1}.
 
@@ -2354,12 +2333,6 @@ lineno_anno(L, St) ->
 	    [Line] ++ St#core.file
     end.
 
-get_ianno(Ce) ->
-    case get_anno(Ce) of
-	#a{}=A -> A;
-	A when is_list(A) -> #a{anno=A}
-    end.
-
 get_lineno_anno(Ce) ->
     case get_anno(Ce) of
 	#a{anno=A} -> A;
diff --git a/lib/compiler/src/v3_kernel.erl b/lib/compiler/src/v3_kernel.erl
index 08e84efc1b..0ac1aaf158 100644
--- a/lib/compiler/src/v3_kernel.erl
+++ b/lib/compiler/src/v3_kernel.erl
@@ -273,17 +273,7 @@ expr(#c_tuple{anno=A,es=Ces}, Sub, St0) ->
     {Kes,Ep,St1} = atomic_list(Ces, Sub, St0),
     {#k_tuple{anno=A,es=Kes},Ep,St1};
 expr(#c_map{anno=A,arg=Var,es=Ces}, Sub, St0) ->
-    try expr_map(A,Var,Ces,Sub,St0) of
-	{_,_,_}=Res -> Res
-    catch
-	throw:bad_map ->
-	    St1 = add_warning(get_line(A), bad_map, A, St0),
-	    Erl = #c_literal{val=erlang},
-	    Name = #c_literal{val=error},
-	    Args = [#c_literal{val=badarg}],
-	    Error = #c_call{anno=A,module=Erl,name=Name,args=Args},
-	    expr(Error, Sub, St1)
-    end;
+    expr_map(A, Var, Ces, Sub, St0);
 expr(#c_binary{anno=A,segments=Cv}, Sub, St0) ->
     try atomic_bin(Cv, Sub, St0) of
 	{Kv,Ep,St1} ->
@@ -506,19 +496,9 @@ translate_fc(Args) ->
     [#c_literal{val=function_clause},make_list(Args)].
 
 expr_map(A,Var0,Ces,Sub,St0) ->
-    %% An extra pass of validation of Map src because of inlining
     {Var,Mps,St1} = expr(Var0, Sub, St0),
-    case is_valid_map_src(Var) of
-	true ->
-	    {Km,Eps,St2} = map_split_pairs(A, Var, Ces, Sub, St1),
-	    {Km,Eps++Mps,St2};
-	false -> throw(bad_map)
-    end.
-
-is_valid_map_src(#k_map{}) -> true;
-is_valid_map_src(#k_literal{val=M}) when is_map(M) -> true;
-is_valid_map_src(#k_var{}) -> true;
-is_valid_map_src(_) -> false.
+    {Km,Eps,St2} = map_split_pairs(A, Var, Ces, Sub, St1),
+    {Km,Eps++Mps,St2}.
 
 map_split_pairs(A, Var, Ces, Sub, St0) ->
     %% 1. Force variables.
@@ -2024,9 +2004,7 @@ format_error(nomatch_shadow) ->
 format_error(bad_call) ->
     "invalid module and/or function name; this call will always fail";
 format_error(bad_segment_size) ->
-    "binary construction will fail because of a type mismatch";
-format_error(bad_map) ->
-    "map construction will fail because of a type mismatch".
+    "binary construction will fail because of a type mismatch".
 
 add_warning(none, Term, Anno, #kern{ws=Ws}=St) ->
     File = get_file(Anno),
diff --git a/lib/compiler/test/beam_validator_SUITE.erl b/lib/compiler/test/beam_validator_SUITE.erl
index c441f9f284..1b1c7db0e8 100644
--- a/lib/compiler/test/beam_validator_SUITE.erl
+++ b/lib/compiler/test/beam_validator_SUITE.erl
@@ -122,7 +122,7 @@ yrange(Config) when is_list(Config) ->
 	  {{move,{x,1},{y,-1}},5,
 	   {invalid_store,{y,-1},term}}},
 	 {{t,sum_2,2},
-	  {{bif,'+',{f,0},[{x,0},{y,1024}],{x,0}},8,
+	  {{bif,'+',{f,0},[{x,0},{y,1024}],{x,0}},7,
 	   {uninitialized_reg,{y,1024}}}},
 	 {{t,sum_3,2},
 	  {{move,{x,1},{y,1024}},5,limit}},
@@ -133,11 +133,11 @@ yrange(Config) when is_list(Config) ->
 
 stack(Config) when is_list(Config) ->
     Errors = do_val(stack, Config),
-    [{{t,a,2},{return,11,{stack_frame,2}}},
+    [{{t,a,2},{return,9,{stack_frame,2}}},
      {{t,b,2},{{deallocate,2},4,{allocated,none}}},
      {{t,bad_1,0},{{allocate_zero,2,10},4,{{x,9},not_live}}},
      {{t,bad_2,0},{{move,{y,0},{x,0}},5,{unassigned,{y,0}}}},
-     {{t,c,2},{{deallocate,2},12,{allocated,none}}},
+     {{t,c,2},{{deallocate,2},10,{allocated,none}}},
      {{t,d,2},
       {{allocate,2,2},5,{existing_stack_frame,{size,2}}}},
      {{t,e,2},{{deallocate,5},6,{allocated,2}}}] = Errors,
@@ -145,18 +145,18 @@ stack(Config) when is_list(Config) ->
 
 call_last(Config) when is_list(Config) ->
     Errors = do_val(call_last, Config),
-    ?line [{{t,a,1},{{call_last,1,{f,8},2},11,{allocated,1}}},
-	   {{t,b,1},
-	    {{call_ext_last,2,{extfunc,lists,seq,2},2},
-	     11,
-	     {allocated,1}}}] = Errors,
+    [{{t,a,1},{{call_last,1,{f,8},2},9,{allocated,1}}},
+     {{t,b,1},
+      {{call_ext_last,2,{extfunc,lists,seq,2},2},
+       10,
+       {allocated,1}}}] = Errors,
     ok.
 
 merge_undefined(Config) when is_list(Config) ->
     Errors = do_val(merge_undefined, Config),
     [{{t,handle_call,2},
       {{call_ext,2,{extfunc,debug,filter,2}},
-       23,
+       22,
        {uninitialized_reg,{y,0}}}}] = Errors,
     ok.
 
@@ -166,10 +166,10 @@ uninit(Config) when is_list(Config) ->
 	[{{t,sum_1,2},
 	  {{move,{y,0},{x,0}},5,{uninitialized_reg,{y,0}}}},
 	 {{t,sum_2,2},
-	  {{call,1,{f,8}},6,{uninitialized_reg,{y,0}}}},
+	  {{call,1,{f,8}},5,{uninitialized_reg,{y,0}}}},
 	 {{t,sum_3,2},
 	  {{bif,'+',{f,0},[{x,0},{y,0}],{x,0}},
-	   7,
+	   6,
 	   {unassigned,{y,0}}}}] = Errors,
     ok.
 
@@ -198,7 +198,7 @@ overwrite_trytag(Config) when is_list(Config) ->
     Errors = do_val(overwrite_trytag, Config),
     ?line
 	[{{overwrite_trytag,foo,1},
-	  {{kill,{y,2}},9,{trytag,_}}}] = Errors,
+	  {{kill,{y,2}},8,{trytag,_}}}] = Errors,
     ok.
 
 accessing_tags(Config) when is_list(Config) ->
@@ -335,7 +335,7 @@ state_after_fault_in_catch(Config) when is_list(Config) ->
 no_exception_in_catch(Config) when is_list(Config) ->
     Errors = do_val(no_exception_in_catch, Config),
     [{{no_exception_in_catch,nested_of_1,4},
-      {{move,{x,3},{x,0}},91,{uninitialized_reg,{x,3}}}}] = Errors,
+      {{move,{x,3},{x,0}},88,{uninitialized_reg,{x,3}}}}] = Errors,
     ok.
 
 undef_label(Config) when is_list(Config) ->
diff --git a/lib/compiler/test/guard_SUITE.erl b/lib/compiler/test/guard_SUITE.erl
index 8db47ffa40..08279d9408 100644
--- a/lib/compiler/test/guard_SUITE.erl
+++ b/lib/compiler/test/guard_SUITE.erl
@@ -1802,6 +1802,12 @@ bad_guards(Config) when is_list(Config) ->
     fc(catch bad_guards_2(#{a=>0,b=>0}, [x])),
     fc(catch bad_guards_2(not_a_map, [x])),
     fc(catch bad_guards_2(42, [x])),
+
+    fc(catch bad_guards_3(#{a=>0,b=>0}, [])),
+    fc(catch bad_guards_3(#{a=>0,b=>0}, [x])),
+    fc(catch bad_guards_3(not_a_map, [x])),
+    fc(catch bad_guards_3(42, [x])),
+
     ok.
 
 %% beam_bool used to produce GC BIF instructions whose
@@ -1813,6 +1819,12 @@ bad_guards_1(X, [_]) when {{X}}, -X ->
 bad_guards_2(M, [_]) when M#{a := 0, b => 0}, map_size(M) ->
     ok.
 
+%% beam_type used to produce an GC BIF instruction whose Live operand
+%% included uninitialized registers.
+
+bad_guards_3(M, [_]) when is_map(M) andalso M#{a := 0, b => 0}, length(M) ->
+    ok.
+
 %% Call this function to turn off constant propagation.
 id(I) -> I.
 
diff --git a/lib/compiler/test/warnings_SUITE.erl b/lib/compiler/test/warnings_SUITE.erl
index 6663985ad7..dcd3910926 100644
--- a/lib/compiler/test/warnings_SUITE.erl
+++ b/lib/compiler/test/warnings_SUITE.erl
@@ -580,11 +580,11 @@ maps(Config) when is_list(Config) ->
            <<"
              t() ->
 		 M = {a,[]},
-		 {'EXIT',{badarg,_}} = (catch(M#{ a => 1})),
+		 {'EXIT',{badarg,_}} = (catch(M#{ a => 1 })),
 		 ok.
            ">>,
            [],
-	   {warnings,[{4,v3_kernel,bad_map}]}},
+	   {warnings,[{4,sys_core_fold,{eval_failure,badarg}}]}},
 	   {bad_map_src2,
            <<"
              t() ->
@@ -594,7 +594,7 @@ maps(Config) when is_list(Config) ->
 	     id(I) -> I.
            ">>,
 	   [inline],
-	   {warnings,[{4,v3_kernel,bad_map}]}},
+	    []},
 	   {bad_map_src3,
            <<"
              t() ->