Revert "beam_ssa_opt: Optimize `=/=` and `=`"

This reverts commit 768993d21d25e67bd4fbc1a587226cfd3dc6cdec.

1 files changed, 3 insertions, 48 deletions

diff --git a/lib/compiler/src/beam_ssa_opt.erl b/lib/compiler/src/beam_ssa_opt.erl
index 625e91f619..00d57ca7a9 100644
--- a/lib/compiler/src/beam_ssa_opt.erl
+++ b/lib/compiler/src/beam_ssa_opt.erl
@@ -39,9 +39,9 @@
 
 -include("beam_ssa_opt.hrl").
 
--import(lists, [all/2,append/1,duplicate/2,flatten/1,foldl/3,
-                keyfind/3,last/1,member/2,reverse/1,reverse/2,
-                splitwith/2,sort/1,takewhile/2,unzip/1]).
+-import(lists, [all/2,append/1,duplicate/2,flatten/1,foldl/3,keyfind/3,
+                member/2,reverse/1,reverse/2,splitwith/2,sort/1,
+                takewhile/2,unzip/1]).
 
 -define(MAX_REPETITIONS, 16).
 
@@ -271,7 +271,6 @@ module_passes(Opts) ->
 %% are repeated as required.
 repeated_passes(Opts) ->
     Ps = [?PASS(ssa_opt_live),
-          ?PASS(ssa_opt_ne),
           ?PASS(ssa_opt_bs_puts),
           ?PASS(ssa_opt_dead),
           ?PASS(ssa_opt_cse),
@@ -2019,50 +2018,6 @@ opt_sw([], Count, Acc) ->
     {reverse(Acc),Count}.
 
 %%%
-%%% Try to replace `=/=` with `=:=` and `/=` with `==`. For example,
-%%% this code:
-%%%
-%%%    Bool = bif:'=/=' Anything, AnyValue
-%%%    br Bool, ^Succ, ^Fail
-%%%
-%%% can be rewritten like this:
-%%%
-%%%    Bool = bif:'=:=' Anything, AnyValue
-%%%    br Bool, ^Fail, ^Succ
-%%%
-%%% This transformation is not an optimization in itself, but it opens
-%%% up for other optimizations in beam_ssa_type and beam_ssa_dead.
-%%%
-
-ssa_opt_ne({#opt_st{ssa=Linear}=St, FuncDb}) ->
-    {St#opt_st{ssa=opt_ne(Linear)}, FuncDb}.
-
-opt_ne([{L,#b_blk{is=[_|_]=Is0,last=#b_br{bool=#b_var{}=Bool}}=Blk0}|Bs]) ->
-    case last(Is0) of
-        #b_set{op={bif,'=/='},dst=Bool}=I0 ->
-            I = I0#b_set{op={bif,'=:='}},
-            Blk = opt_ne_replace(I, Blk0),
-            [{L,Blk}|opt_ne(Bs)];
-        #b_set{op={bif,'/='},dst=Bool}=I0 ->
-            I = I0#b_set{op={bif,'=='}},
-            Blk = opt_ne_replace(I, Blk0),
-            [{L,Blk}|opt_ne(Bs)];
-        _ ->
-            [{L,Blk0}|opt_ne(Bs)]
-    end;
-opt_ne([{L,Blk}|Bs]) ->
-    [{L,Blk}|opt_ne(Bs)];
-opt_ne([]) -> [].
-
-opt_ne_replace(I, #b_blk{is=Is0,last=#b_br{succ=Succ,fail=Fail}=Br0}=Blk) ->
-    Is = replace_last(Is0, I),
-    Br = Br0#b_br{succ=Fail,fail=Succ},
-    Blk#b_blk{is=Is,last=Br}.
-
-replace_last([_], Repl) -> [Repl];
-replace_last([I|Is], Repl) -> [I|replace_last(Is, Repl)].
-
-%%%
 %%% Merge blocks.
 %%%