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| author | Björn Gustavsson <[email protected]> | 2018-01-10 13:09:33 +0100 |
|---|---|---|
| committer | Björn Gustavsson <[email protected]> | 2018-01-11 12:00:59 +0100 |
| commit | ce67e91a851273c8aee58f7dad270c39f18fe0de (patch) | |
| tree | bf096d8821e4afaee7d2dbdeb0ee5cd428fac3ac | |
| parent | ad72a944c03095c3505cb151c9a93d243fb698b6 (diff) | |
| download | otp-ce67e91a851273c8aee58f7dad270c39f18fe0de.tar.gz otp-ce67e91a851273c8aee58f7dad270c39f18fe0de.tar.bz2 otp-ce67e91a851273c8aee58f7dad270c39f18fe0de.zip | |
beam_block: Reorder element/2 calls in guards
In a guard, reorder two consecutive calls to the element/2 BIF that
access the same tuple and have the same failure label so that highest
index is fetched first. That will allow the second element/2 to be
replace with the slightly cheaper get_tuple_element/3 instruction.
| -rw-r--r-- | lib/compiler/src/beam_block.erl | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/compiler/src/beam_block.erl b/lib/compiler/src/beam_block.erl index 570fc05ae5..7b3a95e03e 100644 --- a/lib/compiler/src/beam_block.erl +++ b/lib/compiler/src/beam_block.erl @@ -240,6 +240,10 @@ opt([{set,_,_,{line,_}}=Line1, {set,[D2],[{integer,Idx2},Reg],{bif,element,{f,0}}}=I2|Is]) when Idx1 < Idx2, D1 =/= D2, D1 =/= Reg, D2 =/= Reg -> opt([Line2,I2,Line1,I1|Is]); +opt([{set,[D1],[{integer,Idx1},Reg],{bif,element,{f,L}}}=I1, + {set,[D2],[{integer,Idx2},Reg],{bif,element,{f,L}}}=I2|Is]) + when Idx1 < Idx2, D1 =/= D2, D1 =/= Reg, D2 =/= Reg -> + opt([I2,I1|Is]); opt([{set,Ds0,Ss,Op}|Is0]) -> {Ds,Is} = opt_moves(Ds0, Is0), [{set,Ds,Ss,Op}|opt(Is)]; |