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author | Björn Gustavsson <[email protected]> | 2015-09-23 12:30:16 +0200 |
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committer | Björn Gustavsson <[email protected]> | 2015-09-28 10:26:40 +0200 |
commit | b66193afc3fe85072da4631c52c5ccec136caa05 (patch) | |
tree | 18fa64027bd9b301c7df8f8d2badefb0ad1e66fc /lib/compiler/src/beam_block.erl | |
parent | c0c5943c3a2646a3383d974c2a1afcff8c5d16d3 (diff) | |
download | otp-b66193afc3fe85072da4631c52c5ccec136caa05.tar.gz otp-b66193afc3fe85072da4631c52c5ccec136caa05.tar.bz2 otp-b66193afc3fe85072da4631c52c5ccec136caa05.zip |
beam_type: Improve optimizations by keeping track of booleans
There is an optimization in beam_block to simplify a select_val
on a known boolean value. We can implement this optimization
in a cleaner way in beam_type and it will also be applicable
in more situations. (When I added the optimization to beam_type
without removing the optimization from beam_block, the optimization
was applied 66 times.)
Diffstat (limited to 'lib/compiler/src/beam_block.erl')
-rw-r--r-- | lib/compiler/src/beam_block.erl | 34 |
1 files changed, 0 insertions, 34 deletions
diff --git a/lib/compiler/src/beam_block.erl b/lib/compiler/src/beam_block.erl index 741fdbb973..10dbaf462c 100644 --- a/lib/compiler/src/beam_block.erl +++ b/lib/compiler/src/beam_block.erl @@ -58,33 +58,6 @@ blockify(Is) -> blockify([{loop_rec,{f,Fail},{x,0}},{loop_rec_end,_Lbl},{label,Fail}|Is], Acc) -> %% Useless instruction sequence. blockify(Is, Acc); -blockify([{test,is_atom,{f,Fail},[Reg]}=I| - [{select,select_val,Reg,{f,Fail}, - [{atom,false},{f,_}=BrFalse, - {atom,true}=AtomTrue,{f,_}=BrTrue]}|Is]=Is0], - [{block,Bl}|_]=Acc) -> - case is_last_bool(Bl, Reg) of - false -> - blockify(Is0, [I|Acc]); - true -> - %% The last instruction is a boolean operator/guard BIF that can't fail. - %% We can convert the three-way branch to a two-way branch (eliminating - %% the reference to the failure label). - blockify(Is, [{jump,BrTrue}, - {test,is_eq_exact,BrFalse,[Reg,AtomTrue]}|Acc]) - end; -blockify([{test,is_atom,{f,Fail},[Reg]}=I| - [{select,select_val,Reg,{f,Fail}, - [{atom,true}=AtomTrue,{f,_}=BrTrue, - {atom,false},{f,_}=BrFalse]}|Is]=Is0], - [{block,Bl}|_]=Acc) -> - case is_last_bool(Bl, Reg) of - false -> - blockify(Is0, [I|Acc]); - true -> - blockify(Is, [{jump,BrTrue}, - {test,is_eq_exact,BrFalse,[Reg,AtomTrue]}|Acc]) - end; blockify([I|Is0]=IsAll, Acc) -> case collect(I) of error -> blockify(Is0, [I|Acc]); @@ -94,13 +67,6 @@ blockify([I|Is0]=IsAll, Acc) -> end; blockify([], Acc) -> reverse(Acc). -is_last_bool([{set,[Reg],As,{bif,N,_}}], Reg) -> - Ar = length(As), - erl_internal:new_type_test(N, Ar) orelse erl_internal:comp_op(N, Ar) - orelse erl_internal:bool_op(N, Ar); -is_last_bool([_|Is], Reg) -> is_last_bool(Is, Reg); -is_last_bool([], _) -> false. - collect_block(Is) -> collect_block(Is, []). |