From 7b10ff77235532923558a30759ed9b5fe6d994a5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Mon, 8 Dec 2014 12:33:12 +0100 Subject: beam_dead: Optimize branches from relational conditionals The BEAM compiler translates code such as: is_hex_digit(D) when $0 =< D, D =< $9 -> true; is_hex_digit(D) when $a =< D, D =< $z -> true; is_hex_digit(D) when $A =< D, D =< $Z -> true; is_hex_digit(_) -> false. to something like this: L0: test is_ge L1 {x,0} 48 test is_ge L1 57 {x,0} move true {x,0} return. L1: test is_ge L2 {x,0} 97 test is_ge L2 122 {x,0} move true {x,0} return L2: test is_ge L3 {x,0} 65 test is_ge L3 90 {x,0} move true {x,0} return L3: move false {x,0} return We can see that tests will be repeated even if they cannot possibly succeed. For instance, if we pass in {x,0} equal to 32, the first test that {x,0} is greater than or equal to 48 at L0 will fail. The control will transfer to L1, where it will be tested whether {x,0} is greater than 97. That test will fail and control will pass to L2, where again the test will fail. The compiler can do better by short-circuiting repeating tests: L0: test is_ge L3 {x,0} 48 test is_ge L1 57 {x,0} move true {x,0} return. L1: test is_ge L2 {x,0} 97 test is_ge L3 122 {x,0} move true {x,0} return L2: test is_ge L3 {x,0} 65 test is_ge L3 90 {x,0} move true {x,0} return L3: move false {x,0} return --- lib/compiler/test/guard_SUITE.erl | 230 +++++++++++++++++++++++++++++++++++++- 1 file changed, 228 insertions(+), 2 deletions(-) (limited to 'lib/compiler/test/guard_SUITE.erl') diff --git a/lib/compiler/test/guard_SUITE.erl b/lib/compiler/test/guard_SUITE.erl index eb205d09a7..689c65f537 100644 --- a/lib/compiler/test/guard_SUITE.erl +++ b/lib/compiler/test/guard_SUITE.erl @@ -30,7 +30,7 @@ old_guard_tests/1, build_in_guard/1,gbif/1, t_is_boolean/1,is_function_2/1, - tricky/1,rel_ops/1,literal_type_tests/1, + tricky/1,rel_ops/1,rel_op_combinations/1,literal_type_tests/1, basic_andalso_orelse/1,traverse_dcd/1, check_qlc_hrl/1,andalso_semi/1,t_tuple_size/1,binary_part/1, bad_constants/1,bad_guards/1]). @@ -47,7 +47,8 @@ groups() -> semicolon,complex_semicolon,comma,or_guard, more_or_guards,complex_or_guards,and_guard,xor_guard, more_xor_guards,build_in_guard,old_guard_tests,gbif, - t_is_boolean,is_function_2,tricky,rel_ops, + t_is_boolean,is_function_2,tricky, + rel_ops,rel_op_combinations, literal_type_tests,basic_andalso_orelse,traverse_dcd, check_qlc_hrl,andalso_semi,t_tuple_size,binary_part, bad_constants,bad_guards]}]. @@ -1122,6 +1123,231 @@ rel_ops(Config) when is_list(Config) -> -undef(TestOp). +rel_op_combinations(Config) when is_list(Config) -> + Digits0 = lists:seq(16#0030, 16#0039) ++ + lists:seq(16#0660, 16#0669) ++ + lists:seq(16#06F0, 16#06F9), + Digits = gb_sets:from_list(Digits0), + rel_op_combinations_1(16#0700, Digits), + + BrokenRange0 = lists:seq(3, 5) ++ + lists:seq(10, 12) ++ lists:seq(14, 20), + BrokenRange = gb_sets:from_list(BrokenRange0), + rel_op_combinations_2(30, BrokenRange), + + Red0 = [{I,2*I} || I <- lists:seq(0, 50)] ++ + [{I,5*I} || I <- lists:seq(51, 80)], + Red = gb_trees:from_orddict(Red0), + rel_op_combinations_3(100, Red). + +rel_op_combinations_1(0, _) -> + ok; +rel_op_combinations_1(N, Digits) -> + Bool = gb_sets:is_member(N, Digits), + Bool = is_digit_1(N), + Bool = is_digit_2(N), + Bool = is_digit_3(N), + Bool = is_digit_4(N), + Bool = is_digit_5(N), + Bool = is_digit_6(N), + Bool = is_digit_7(N), + Bool = is_digit_8(N), + rel_op_combinations_1(N-1, Digits). + +is_digit_1(X) when 16#0660 =< X, X =< 16#0669 -> true; +is_digit_1(X) when 16#0030 =< X, X =< 16#0039 -> true; +is_digit_1(X) when 16#06F0 =< X, X =< 16#06F9 -> true; +is_digit_1(_) -> false. + +is_digit_2(X) when (16#0030-1) < X, X =< 16#0039 -> true; +is_digit_2(X) when (16#0660-1) < X, X =< 16#0669 -> true; +is_digit_2(X) when (16#06F0-1) < X, X =< 16#06F9 -> true; +is_digit_2(_) -> false. + +is_digit_3(X) when 16#0660 =< X, X < (16#0669+1) -> true; +is_digit_3(X) when 16#0030 =< X, X < (16#0039+1) -> true; +is_digit_3(X) when 16#06F0 =< X, X < (16#06F9+1) -> true; +is_digit_3(_) -> false. + +is_digit_4(X) when (16#0660-1) < X, X < (16#0669+1) -> true; +is_digit_4(X) when (16#0030-1) < X, X < (16#0039+1) -> true; +is_digit_4(X) when (16#06F0-1) < X, X < (16#06F9+1) -> true; +is_digit_4(_) -> false. + +is_digit_5(X) when X >= 16#0660, X =< 16#0669 -> true; +is_digit_5(X) when X >= 16#0030, X =< 16#0039 -> true; +is_digit_5(X) when X >= 16#06F0, X =< 16#06F9 -> true; +is_digit_5(_) -> false. + +is_digit_6(X) when X > (16#0660-1), X =< 16#0669 -> true; +is_digit_6(X) when X > (16#0030-1), X =< 16#0039 -> true; +is_digit_6(X) when X > (16#06F0-1), X =< 16#06F9 -> true; +is_digit_6(_) -> false. + +is_digit_7(X) when 16#0660 =< X, X =< 16#0669 -> true; +is_digit_7(X) when 16#0030 =< X, X =< 16#003A, X =/= 16#003A -> true; +is_digit_7(X) when 16#06F0 =< X, X =< 16#06F9 -> true; +is_digit_7(_) -> false. + +is_digit_8(X) when X =< 16#0039, X > (16#0030-1) -> true; +is_digit_8(X) when X =< 16#06F9, X > (16#06F0-1) -> true; +is_digit_8(X) when X =< 16#0669, X > (16#0660-1) -> true; +is_digit_8(16#0670) -> false; +is_digit_8(_) -> false. + +rel_op_combinations_2(0, _) -> + ok; +rel_op_combinations_2(N, Range) -> + Bool = gb_sets:is_member(N, Range), + Bool = broken_range_1(N), + Bool = broken_range_2(N), + Bool = broken_range_3(N), + Bool = broken_range_4(N), + Bool = broken_range_5(N), + Bool = broken_range_6(N), + Bool = broken_range_7(N), + Bool = broken_range_8(N), + Bool = broken_range_9(N), + Bool = broken_range_10(N), + Bool = broken_range_11(N), + Bool = broken_range_12(N), + Bool = broken_range_13(N), + rel_op_combinations_2(N-1, Range). + +broken_range_1(X) when X >= 10, X =< 20, X =/= 13 -> true; +broken_range_1(X) when X >= 3, X =< 5 -> true; +broken_range_1(_) -> false. + +broken_range_2(X) when X >= 10, X =< 12 -> true; +broken_range_2(X) when X >= 14, X =< 20 -> true; +broken_range_2(X) when X >= 3, X =< 5 -> true; +broken_range_2(_) -> false. + +broken_range_3(X) when X >= 10, X =< 12 -> true; +broken_range_3(X) when X >= 14, X < 21 -> true; +broken_range_3(3) -> true; +broken_range_3(4) -> true; +broken_range_3(5) -> true; +broken_range_3(_) -> false. + +broken_range_4(X) when X =< 5, X >= 3 -> true; +broken_range_4(X) when X >= 10, X =< 20, X =/= 13 -> true; +broken_range_4(X) when X =< 100 -> false; +broken_range_4(_) -> false. + +broken_range_5(X) when X >= 10, X =< 20, X =/= 13 -> true; +broken_range_5(X) when X > 2, X =< 5 -> true; +broken_range_5(_) -> false. + +broken_range_6(X) when X >= 10, X =< 20, X =/= 13 -> true; +broken_range_6(X) when X > 2, X < 6 -> true; +broken_range_6(_) -> false. + +broken_range_7(X) when X > 2, X < 6 -> true; +broken_range_7(X) when X >= 10, X =< 20, X =/= 13 -> true; +broken_range_7(X) when X > 30 -> false; +broken_range_7(_) -> false. + +broken_range_8(X) when X >= 10, X =< 20, X =/= 13 -> true; +broken_range_8(X) when X =:= 3 -> true; +broken_range_8(X) when X >= 3, X =< 5 -> true; +broken_range_8(_) -> false. + +broken_range_9(X) when X >= 10, X =< 20, X =/= 13 -> true; +broken_range_9(X) when X =:= 13 -> false; +broken_range_9(X) when X >= 3, X =< 5 -> true; +broken_range_9(_) -> false. + +broken_range_10(X) when X >= 3, X =< 5 -> true; +broken_range_10(X) when X >= 10, X =< 20, X =/= 13 -> true; +broken_range_10(X) when X =/= 13 -> false; +broken_range_10(_) -> false. + +broken_range_11(X) when X >= 10, X =< 20, X =/= 13 -> true; +broken_range_11(X) when is_tuple(X), X =:= 10 -> true; +broken_range_11(X) when X >= 3, X =< 5 -> true; +broken_range_11(_) -> false. + +broken_range_12(X) when X >= 3, X =< 5 -> true; +broken_range_12(X) when X >= 10, X =< 20, X =/= 13 -> true; +broken_range_12(X) when X < 30, X > 20 -> false; +broken_range_12(_) -> false. + +broken_range_13(X) when X >= 10, X =< 20, 13 =/= X -> true; +broken_range_13(X) when X >= 3, X =< 5 -> true; +broken_range_13(_) -> false. + +rel_op_combinations_3(0, _) -> + ok; +rel_op_combinations_3(N, Red) -> + Val = case gb_trees:lookup(N, Red) of + none -> none; + {value,V} -> V + end, + Val = redundant_1(N), + Val = redundant_2(N), + Val = redundant_3(N), + Val = redundant_4(N), + Val = redundant_5(N), + Val = redundant_6(N), + Val = redundant_7(N), + Val = redundant_8(N), + Val = redundant_9(N), + Val = redundant_10(N), + Val = redundant_11(N), + rel_op_combinations_3(N-1, Red). + +redundant_1(X) when X >= 51, X =< 80 -> 5*X; +redundant_1(X) when X < 51 -> 2*X; +redundant_1(_) -> none. + +redundant_2(X) when X < 51 -> 2*X; +redundant_2(X) when X >= 51, X =< 80 -> 5*X; +redundant_2(_) -> none. + +redundant_3(X) when X < 51 -> 2*X; +redundant_3(X) when X =< 80, X >= 51 -> 5*X; +redundant_3(X) when X =/= 100 -> none; +redundant_3(_) -> none. + +redundant_4(X) when X < 51 -> 2*X; +redundant_4(X) when X =< 80, X > 50 -> 5*X; +redundant_4(X) when X =/= 100 -> none; +redundant_4(_) -> none. + +redundant_5(X) when X < 51 -> 2*X; +redundant_5(X) when X > 50, X < 81 -> 5*X; +redundant_5(X) when X =< 10 -> none; +redundant_5(_) -> none. + +redundant_6(X) when X > 50, X =< 80 -> 5*X; +redundant_6(X) when X < 51 -> 2*X; +redundant_6(_) -> none. + +redundant_7(X) when is_integer(X), X >= 51, X =< 80 -> 5*X; +redundant_7(X) when is_integer(X), X < 51 -> 2*X; +redundant_7(_) -> none. + +redundant_8(X) when X >= 51, X =< 80 -> 5*X; +redundant_8(X) when X < 51 -> 2*X; +redundant_8(_) -> none. + +redundant_9(X) when X >= 51, X =< 80 -> 5*X; +redundant_9(X) when X < 51 -> 2*X; +redundant_9(90) -> none; +redundant_9(X) when X =/= 90 -> none; +redundant_9(_) -> none. + +redundant_10(X) when X >= 51, X =< 80 -> 5*X; +redundant_10(X) when X < 51 -> 2*X; +redundant_10(90) -> none; +redundant_10(X) when X =:= 90 -> none; +redundant_10(_) -> none. + +redundant_11(X) when X < 51 -> 2*X; +redundant_11(X) when X =:= 10 -> 2*X; +redundant_11(X) when X >= 51, X =< 80 -> 5*X; +redundant_11(_) -> none. %% Test type tests on literal values. (From emulator test suites.) literal_type_tests(Config) when is_list(Config) -> -- cgit v1.2.3