From 1cbc6a430d18d80a0b5e6ad0f7f1010d5394056a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Muska=C5=82a?= Date: Thu, 23 Nov 2017 21:27:40 +0100 Subject: Place move S x0 instructions at the end of blocks The loader has a lot of fused instructions that include move S x0. Placing them at the end of blocks makes it possible to take advantage of this optimization more frequently. --- lib/compiler/src/beam_block.erl | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'lib/compiler/src') diff --git a/lib/compiler/src/beam_block.erl b/lib/compiler/src/beam_block.erl index 6543e05e20..c640af224d 100644 --- a/lib/compiler/src/beam_block.erl +++ b/lib/compiler/src/beam_block.erl @@ -219,11 +219,20 @@ alloc_may_pass({set,_,_,{set_tuple_element,_}}) -> false; alloc_may_pass({set,_,_,put_list}) -> false; alloc_may_pass({set,_,_,put}) -> false; alloc_may_pass({set,_,_,_}) -> true. - + %% opt([Instruction]) -> [Instruction] %% Optimize the instruction stream inside a basic block. opt([{set,[X],[X],move}|Is]) -> opt(Is); +opt([{set,[X],_,move},{set,[X],_,move}=I|Is]) -> + opt([I|Is]); +opt([{set,[{x,0}],[S1],move}=I1,{set,[D2],[{x,0}],move}|Is]) -> + opt([I1,{set,[D2],[S1],move}|Is]); +opt([{set,[{x,0}],[S1],move}=I1,{set,[D2],[S2],move}|Is0]) when S1 =/= D2 -> + %% Place move S x0 at the end of move sequences so that + %% loader can merge with the following instruction + {Ds,Is} = opt_moves([D2], Is0), + [{set,Ds,[S2],move}|opt([I1|Is])]; opt([{set,_,_,{line,_}}=Line1, {set,[D1],[{integer,Idx1},Reg],{bif,element,{f,0}}}=I1, {set,_,_,{line,_}}=Line2, -- cgit v1.2.3