File 2072-beam_ssa_dead-Extend-combining-of-switches-to-also-i.patch of Package erlang
From 7895cde3bb34a336fe14e28c48f505a26ee6af0d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 26 May 2020 13:01:25 +0200
Subject: [PATCH 2/3] beam_ssa_dead: Extend combining of switches to also
include is_boolean tests
---
lib/compiler/src/beam_ssa_dead.erl | 65 ++++++++++++++++++++----------
lib/compiler/test/guard_SUITE.erl | 50 +++++++++++++++++++++--
2 files changed, 89 insertions(+), 26 deletions(-)
diff --git a/lib/compiler/src/beam_ssa_dead.erl b/lib/compiler/src/beam_ssa_dead.erl
index b4710d6797..cf0132ebb1 100644
--- a/lib/compiler/src/beam_ssa_dead.erl
+++ b/lib/compiler/src/beam_ssa_dead.erl
@@ -852,7 +852,7 @@ eval_type_test_1(Test, Arg) ->
erlang:Test(Arg).
%%%
-%%% Combine bif:'=:=' and switch instructions
+%%% Combine bif:'=:=', is_boolean/1 tests, and switch instructions
%%% to switch instructions.
%%%
%%% Consider this code:
@@ -904,10 +904,11 @@ combine_eqs_1([L|Ls], #st{bs=Blocks0}=St0) ->
none ->
combine_eqs_1(Ls, St0);
{_,Arg,_,Fail0,List0} ->
+ %% Look for a switch instruction at the fail label
case comb_get_sw(Fail0, St0) of
{true,Arg,Fail1,Fail,List1} ->
%% Another switch/br with the same arguments was
- %% found. Try combining them.
+ %% found at the fail label. Try combining them.
case combine_lists(Fail1, List0, List1, Blocks0) of
none ->
%% Different types of literals in the lists,
@@ -916,30 +917,46 @@ combine_eqs_1([L|Ls], #st{bs=Blocks0}=St0) ->
%% (increasing code size and repeating tests).
combine_eqs_1(Ls, St0);
List ->
- %% Everything OK! Combine the lists.
- Sw0 = #b_switch{arg=Arg,fail=Fail,list=List},
- Sw = beam_ssa:normalize(Sw0),
- Blk0 = map_get(L, Blocks0),
- Blk = Blk0#b_blk{last=Sw},
- Blocks = Blocks0#{L:=Blk},
- St = St0#st{bs=Blocks},
+ %% The lists were successfully combined.
+ St = combine_build_sw(L, Arg, Fail, List, St0),
combine_eqs_1(Ls, St)
end;
- {true,_OtherArg,_,_,_} ->
- %% The other switch/br uses a different Arg.
- combine_eqs_1(Ls, St0);
- {false,_,_,_,_} ->
- %% Not safe: Bindings of variables that will be used
- %% or execution of instructions with potential
- %% side effects will be skipped.
- combine_eqs_1(Ls, St0);
- none ->
- %% No switch/br at this label.
- combine_eqs_1(Ls, St0)
+ _ ->
+ %% There was no switch of the correct kind found at the
+ %% fail label. Look for a switch at the first success label.
+ [{_,Succ}|_] = List0,
+ case comb_get_sw(Succ, St0) of
+ {true,Arg,_,_,_} ->
+ %% Since we found a switch at the success
+ %% label, the switch for this block (L)
+ %% must have been constructed out of a
+ %% is_boolean test or a two-way branch
+ %% instruction (if the switch at L had
+ %% been present when the shortcut_opt/1
+ %% pass was run, its success branches
+ %% would have been cut short and no longer
+ %% point at the switch at the fail label).
+ %%
+ %% Therefore, keep this constructed
+ %% switch. It will be further optimized
+ %% the next time shortcut_opt/1 is run.
+ St = combine_build_sw(L, Arg, Fail0, List0, St0),
+ combine_eqs_1(Ls, St);
+ _ ->
+ combine_eqs_1(Ls, St0)
+ end
end
end;
combine_eqs_1([], St) -> St.
+combine_build_sw(From, Arg, Fail, List, #st{bs=Blocks0}=St) ->
+ Sw0 = #b_switch{arg=Arg,fail=Fail,list=List},
+ Sw = beam_ssa:normalize(Sw0),
+ Blk0 = map_get(From, Blocks0),
+ Blk = Blk0#b_blk{last=Sw},
+ Blocks = Blocks0#{From := Blk},
+ St#st{bs=Blocks}.
+
comb_get_sw(L, #st{bs=Blocks,skippable=Skippable}) ->
#b_blk{is=Is,last=Last} = map_get(L, Blocks),
Safe0 = is_map_key(L, Skippable),
@@ -948,10 +965,14 @@ comb_get_sw(L, #st{bs=Blocks,skippable=Skippable}) ->
none;
#b_br{bool=#b_var{}=Bool,succ=Succ,fail=Fail} ->
case comb_is(Is, Bool, Safe0) of
- {none,_} ->
- none;
+ {none,Safe} ->
+ {Safe,Bool,L,Fail,[{#b_literal{val=true},Succ}]};
{#b_set{op={bif,'=:='},args=[#b_var{}=Arg,#b_literal{}=Lit]},Safe} ->
{Safe,Arg,L,Fail,[{Lit,Succ}]};
+ {#b_set{op={bif,is_boolean},args=[#b_var{}=Arg]},Safe} ->
+ SwList = [{#b_literal{val=false},Succ},
+ {#b_literal{val=true},Succ}],
+ {Safe,Arg,L,Fail,SwList};
{#b_set{},_} ->
none
end;
diff --git a/lib/compiler/test/guard_SUITE.erl b/lib/compiler/test/guard_SUITE.erl
index 0558b8f300..05ec491efc 100644
--- a/lib/compiler/test/guard_SUITE.erl
+++ b/lib/compiler/test/guard_SUITE.erl
@@ -1084,15 +1084,50 @@ on(V) when number(V) -> number;
on(_) -> not_number.
complex_guard(_Config) ->
- _ = [true = do_complex_guard(X, Y, Z) ||
+ _ = [true = do_complex_guard_1(X, Y, Z) ||
X <- [4,5], Y <- [4,5], Z <- [4,5]],
- _ = [true = do_complex_guard(X, Y, Z) ||
+ _ = [true = do_complex_guard_1(X, Y, Z) ||
X <- [1,2,3], Y <- [1,2,3], Z <- [1,2,3]],
- _ = [catch do_complex_guard(X, Y, Z) ||
+ _ = [catch do_complex_guard_1(X, Y, Z) ||
X <- [1,2,3,4,5], Y <- [0,6], Z <- [1,2,3,4,5]],
+
+ b = do_complex_guard_2(false, false, true),
+ c = do_complex_guard_2(false, false, false),
+ c = do_complex_guard_2(false, true, true),
+ a = do_complex_guard_2(false, true, false),
+
+ c = do_complex_guard_2(true, false, true),
+ a = do_complex_guard_2(true, false, false),
+ c = do_complex_guard_2(true, true, true),
+ a = do_complex_guard_2(true, true, false),
+
+ c = do_complex_guard_2(other, false, true),
+ c = do_complex_guard_2(other, false, false),
+ c = do_complex_guard_2(other, true, true),
+ c = do_complex_guard_2(other, true, false),
+
+ c = do_complex_guard_2(false, other, true),
+ c = do_complex_guard_2(false, other, false),
+ c = do_complex_guard_2(true, other, true),
+ a = do_complex_guard_2(true, other, false),
+
+ c = do_complex_guard_2(false, false, other),
+ c = do_complex_guard_2(false, true, other),
+ c = do_complex_guard_2(true, false, other),
+ c = do_complex_guard_2(true, true, other),
+
+ c = do_complex_guard_2(false, other, other),
+ c = do_complex_guard_2(true, other, other),
+ c = do_complex_guard_2(other, other, true),
+ c = do_complex_guard_2(other, other, false),
+ c = do_complex_guard_2(other, false, other),
+ c = do_complex_guard_2(other, true, other),
+
+ c = do_complex_guard_2(other, other, other),
+
ok.
-do_complex_guard(X1, Y1, Z1) ->
+do_complex_guard_1(X1, Y1, Z1) ->
if
((X1 =:= 4) or (X1 =:= 5)) and
((Y1 =:= 4) or (Y1 =:= 5)) and
@@ -1103,6 +1138,13 @@ do_complex_guard(X1, Y1, Z1) ->
true
end.
+do_complex_guard_2(X, Y, Z) ->
+ if
+ (X orelse Y) andalso (not Z) -> a;
+ Z andalso (not (X orelse Y)) -> b;
+ true -> c
+ end.
+
gbif(Config) when is_list(Config) ->
error = gbif_1(1, {false,true}),
ok = gbif_1(2, {false,true}),
--
2.26.2
