From f9a323d10a9f5da305cbdec632d6bdf7ad4770b5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Muska=C5=82a?= Date: Sat, 26 Aug 2017 15:15:01 +0200 Subject: Optimise equality comparisons * In both loader and compiler, make sure constants are always the second operand - many passes of the compiler assume that's always the case. * In loader rewrite is_eq_exact with same arguments to skip the instruction and with different constants move one to an x register to maintain the properly outlined above. * The same (but in reverse) is done with the is_ne_exact, where we rewrite to an unconditional jump or add a move to an x register. * All of the above allow to replace is_eq_exact_fss with is_eq_exact_fyy and is_ne_exact_fss with is_ne_exact_fSS as those are the only possibilities left. --- erts/emulator/beam/ops.tab | 17 +++++++++++++---- lib/compiler/src/beam_utils.erl | 15 +++++++++++++++ lib/compiler/test/guard_SUITE.erl | 4 ++++ 3 files changed, 32 insertions(+), 4 deletions(-) diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab index b6e995fdbe..ba0aa005c9 100644 --- a/erts/emulator/beam/ops.tab +++ b/erts/emulator/beam/ops.tab @@ -413,9 +413,18 @@ send # Optimized comparisons with one immediate/literal operand. # -is_eq_exact Lbl R=xy C=ian => i_is_eq_exact_immed Lbl R C +is_eq_exact Lbl S S => +is_eq_exact Lbl C1=c C2=c => move C1 x | is_eq_exact Lbl x C2 +is_eq_exact Lbl C=c R=xy => is_eq_exact Lbl R C + +is_eq_exact Lbl R=xy n => is_nil Lbl R +is_eq_exact Lbl R=xy C=ia => i_is_eq_exact_immed Lbl R C is_eq_exact Lbl R=xy C=q => i_is_eq_exact_literal Lbl R C +is_ne_exact Lbl S S => jump Lbl +is_ne_exact Lbl C1=c C2=c => move C1 x | is_ne_exact Lbl x C2 +is_ne_exact Lbl C=c R=xy => is_ne_exact Lbl R C + is_ne_exact Lbl R=xy C=ian => i_is_ne_exact_immed Lbl R C is_ne_exact Lbl R=xy C=q => i_is_ne_exact_literal Lbl R C @@ -429,7 +438,9 @@ i_is_ne_exact_literal f xy c is_eq_exact Lbl Y=y X=x => is_eq_exact Lbl X Y is_eq_exact f x xy -is_eq_exact f s s +is_eq_exact f y y + +is_ne_exact f S S is_lt f x x is_lt f x c @@ -445,8 +456,6 @@ is_ge f c x is_ge f s s %hot -is_ne_exact f s s - is_eq f s s is_ne f s s diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl index 52ed1c7ca0..a4c65397df 100644 --- a/lib/compiler/src/beam_utils.erl +++ b/lib/compiler/src/beam_utils.erl @@ -32,6 +32,11 @@ -import(lists, [map/2,member/2,sort/1,reverse/1,splitwith/2]). +-define(is_const(Val), (element(1, Val) =:= integer orelse + element(1, Val) =:= float orelse + element(1, Val) =:= atom orelse + element(1, Val) =:= literal)). + %% instruction() describes all instructions that are used during optimzation %% (from beam_a to beam_z). -type instruction() :: atom() | tuple(). @@ -197,10 +202,20 @@ bif_to_test('>', [A,B], Fail) -> {test,is_lt,Fail,[B,A]}; bif_to_test('<', [_,_]=Ops, Fail) -> {test,is_lt,Fail,Ops}; bif_to_test('>=', [_,_]=Ops, Fail) -> {test,is_ge,Fail,Ops}; bif_to_test('==', [A,nil], Fail) -> {test,is_nil,Fail,[A]}; +bif_to_test('==', [nil,A], Fail) -> {test,is_nil,Fail,[A]}; +bif_to_test('==', [C,A], Fail) when ?is_const(C) -> + {test,is_eq,Fail,[A,C]}; bif_to_test('==', [_,_]=Ops, Fail) -> {test,is_eq,Fail,Ops}; +bif_to_test('/=', [C,A], Fail) when ?is_const(C) -> + {test,is_ne,Fail,[A,C]}; bif_to_test('/=', [_,_]=Ops, Fail) -> {test,is_ne,Fail,Ops}; bif_to_test('=:=', [A,nil], Fail) -> {test,is_nil,Fail,[A]}; +bif_to_test('=:=', [nil,A], Fail) -> {test,is_nil,Fail,[A]}; +bif_to_test('=:=', [C,A], Fail) when ?is_const(C) -> + {test,is_eq_exact,Fail,[A,C]}; bif_to_test('=:=', [_,_]=Ops, Fail) -> {test,is_eq_exact,Fail,Ops}; +bif_to_test('=/=', [C,A], Fail) when ?is_const(C) -> + {test,is_ne_exact,Fail,[A,C]}; bif_to_test('=/=', [_,_]=Ops, Fail) -> {test,is_ne_exact,Fail,Ops}; bif_to_test(is_record, [_,_,_]=Ops, Fail) -> {test,is_record,Fail,Ops}. diff --git a/lib/compiler/test/guard_SUITE.erl b/lib/compiler/test/guard_SUITE.erl index ccb9b58225..d96cfdb7ac 100644 --- a/lib/compiler/test/guard_SUITE.erl +++ b/lib/compiler/test/guard_SUITE.erl @@ -1291,6 +1291,10 @@ rel_ops(Config) when is_list(Config) -> true = any_atom /= id(42), true = [] /= id(42), + %% Coverage of beam_utils:bif_to_test/3 + Empty = id([]), + ?T(==, [], Empty), + ok. -undef(TestOp). -- cgit v1.2.3