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| author | Björn Gustavsson <[email protected]> | 2013-11-26 09:32:44 +0100 |
|---|---|---|
| committer | Björn Gustavsson <[email protected]> | 2014-01-20 12:22:42 +0100 |
| commit | 48360023d2f5ae72df19f0095da55738f63800db (patch) | |
| tree | dc8f7bf17ced4d9b2aebdfa505badcbce5645ad8 /lib/asn1 | |
| parent | 912b330733144ae37e7a4da1bfea5be2a46d7594 (diff) | |
| download | otp-48360023d2f5ae72df19f0095da55738f63800db.tar.gz otp-48360023d2f5ae72df19f0095da55738f63800db.tar.bz2 otp-48360023d2f5ae72df19f0095da55738f63800db.zip | |
asn1ct_imm: Add the {set,{var,Src},{var,Dst}} instruction
The {assign,Dst,Src} instruction is difficult to cope with when
doing advanced optimizations, since its source argument is a string
which may contain any expression.
Instead of changing how {assign,_,_} works, we will introduce new
instructions that can be used instead of {assign,_}, and remove
{assign,_,_} in a later commit when it is no longer used.
The first new instruction we will introduce is:
{set,{var,Src},{var,Dst}}
It is useful for common sub-expression elemination among other things.
For the moment, we will only allow a variable as a source argument,
but we could extend it in the future to allow constants as well.
Diffstat (limited to 'lib/asn1')
| -rw-r--r-- | lib/asn1/src/asn1ct_imm.erl | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/lib/asn1/src/asn1ct_imm.erl b/lib/asn1/src/asn1ct_imm.erl index 48d380bcbc..9089fdf983 100644 --- a/lib/asn1/src/asn1ct_imm.erl +++ b/lib/asn1/src/asn1ct_imm.erl @@ -978,6 +978,7 @@ is_nonbuilding({call,_,_,_,_}) -> true; is_nonbuilding({call_gen,_,_,_,_,_,_}) -> true; is_nonbuilding({'cond',_,_}) -> true; is_nonbuilding({lc,_,_,_,_}) -> true; +is_nonbuilding({set,_,_}) -> true; is_nonbuilding({sub,_,_,_}) -> true; is_nonbuilding({'try',_,_,_,_}) -> true; is_nonbuilding(_) -> false. @@ -1698,7 +1699,6 @@ enc_pre_cg_nonbuilding({'try',Try0,{P,Succ0},Else0,Dst}, StL) -> {'try',Try,{P,Succ},Else,Dst}; enc_pre_cg_nonbuilding(Imm, _) -> Imm. - %%% %%% Code generation for encoding. %%% @@ -1773,6 +1773,8 @@ enc_cg({sub,Src0,Int,Dst0}) -> Src = mk_val(Src0), Dst = mk_val(Dst0), emit([Dst," = ",Src," - ",Int]); +enc_cg({set,{var,Src},{var,Dst}}) -> + emit([Dst," = ",Src]); enc_cg({'try',Try,{P,Succ},Else,Dst}) -> emit([mk_val(Dst)," = try "]), enc_cg(Try), @@ -2053,6 +2055,8 @@ enc_opt_al({put_bits,_,N,[U]}=PutBits, Al) when is_integer(N), is_integer(Al) -> {[PutBits],Al+N*U}; enc_opt_al({put_bits,_,binary,[U]}=PutBits, Al) when U rem 8 =:= 0 -> {[PutBits],Al}; +enc_opt_al({set,_,_}=Imm, Al) -> + {[Imm],Al}; enc_opt_al({sub,_,_,_}=Imm, Al) -> {[Imm],Al}; enc_opt_al({'try',_,_,_,_}=Imm, Al) -> @@ -2138,6 +2142,8 @@ per_fixup([{lc,B,V,L}|T]) -> [{lc,per_fixup(B),V,L}|per_fixup(T)]; per_fixup([{lc,B,V,L,Dst}|T]) -> [{lc,per_fixup(B),V,L,Dst}|per_fixup(T)]; +per_fixup([{set,_,_}=H|T]) -> + [H|per_fixup(T)]; per_fixup([{sub,_,_,_}=H|T]) -> [H|per_fixup(T)]; per_fixup([{'try',Try0,{P,Succ0},Else0,Dst}|T]) -> |