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authorBjörn Gustavsson <[email protected]>2015-01-23 13:12:09 +0100
committerBjörn Gustavsson <[email protected]>2015-02-03 09:39:32 +0100
commit4babd738633953a09ce3314ed89d0933063b4ef7 (patch)
tree4975109d3d64e76fdc4ba5a7e7e3ecdef586ef11 /lib/compiler/test
parentcd1eaf0116190ab72f3a792b74be99eda5dd31eb (diff)
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Teach case_opt/3 to avoid unnecessary building
Given this code: f(S) -> F0 = F1 = {S,S}, [F0,F1]. case_opt/3 would "optimize" it like this: f(S) -> F1 = {S,S}, F0 = {S,S}, [F0,F1]. Similarly, this code: g({a,_,_}=T) -> {b, [_,_] = [T,none], x}. would be rewritten to: g({a,Tmp1,Tmp2}=T) -> Tmp3 = {a,Tmp1,Tmp2}, {b, [Tmp3,none], x}. where the tuple is rebuilt instead of using the T variable. Rewrite case_opt/3 to be more careful while optimizing.
Diffstat (limited to 'lib/compiler/test')
-rw-r--r--lib/compiler/test/core_fold_SUITE.erl31
-rw-r--r--lib/compiler/test/test_lib.erl4
2 files changed, 32 insertions, 3 deletions
diff --git a/lib/compiler/test/core_fold_SUITE.erl b/lib/compiler/test/core_fold_SUITE.erl
index bca8afb1b0..b45874433c 100644
--- a/lib/compiler/test/core_fold_SUITE.erl
+++ b/lib/compiler/test/core_fold_SUITE.erl
@@ -23,7 +23,8 @@
t_element/1,setelement/1,t_length/1,append/1,t_apply/1,bifs/1,
eq/1,nested_call_in_case/1,guard_try_catch/1,coverage/1,
unused_multiple_values_error/1,unused_multiple_values/1,
- multiple_aliases/1,redundant_boolean_clauses/1,mixed_matching_clauses/1]).
+ multiple_aliases/1,redundant_boolean_clauses/1,
+ mixed_matching_clauses/1,unnecessary_building/1]).
-export([foo/0,foo/1,foo/2,foo/3]).
@@ -40,7 +41,8 @@ groups() ->
[t_element,setelement,t_length,append,t_apply,bifs,
eq,nested_call_in_case,guard_try_catch,coverage,
unused_multiple_values_error,unused_multiple_values,
- multiple_aliases,redundant_boolean_clauses,mixed_matching_clauses]}].
+ multiple_aliases,redundant_boolean_clauses,
+ mixed_matching_clauses,unnecessary_building]}].
init_per_suite(Config) ->
@@ -403,4 +405,29 @@ mixed_matching_clauses(Config) when is_list(Config) ->
end,
ok.
+unnecessary_building(Config) when is_list(Config) ->
+ Term1 = do_unnecessary_building_1(test_lib:id(a)),
+ [{a,a},{a,a}] = Term1,
+ 7 = erts_debug:size(Term1),
+
+ %% The Input term should not be rebuilt (thus, it should
+ %% only be counted once in the size of the combined term).
+ Input = test_lib:id({a,b,c}),
+ Term2 = test_lib:id(do_unnecessary_building_2(Input)),
+ {b,[{a,b,c},none],x} = Term2,
+ 4+4+4+2 = erts_debug:size([Term2|Input]),
+
+ ok.
+
+do_unnecessary_building_1(S) ->
+ %% The tuple must only be built once.
+ F0 = F1 = {S,S},
+ [F0,F1].
+
+do_unnecessary_building_2({a,_,_}=T) ->
+ %% The T term should not be rebuilt.
+ {b,
+ [_,_] = [T,none],
+ x}.
+
id(I) -> I.
diff --git a/lib/compiler/test/test_lib.erl b/lib/compiler/test/test_lib.erl
index e06e42276a..e8f469c5b4 100644
--- a/lib/compiler/test/test_lib.erl
+++ b/lib/compiler/test/test_lib.erl
@@ -20,9 +20,11 @@
-include("test_server.hrl").
-compile({no_auto_import,[binary_part/2]}).
--export([recompile/1,parallel/0,uniq/0,opt_opts/1,get_data_dir/1,
+-export([id/1,recompile/1,parallel/0,uniq/0,opt_opts/1,get_data_dir/1,
smoke_disasm/1,p_run/2,binary_part/2]).
+id(I) -> I.
+
recompile(Mod) when is_atom(Mod) ->
case whereis(cover_server) of
undefined -> ok;