From 9cfd4261240fffc51ca5aa7d1df5a29a30f42a38 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Mon, 28 Jan 2013 10:51:11 +0100 Subject: compiler: Use the literal pool for floating point constants The BEAM loader will put floating point constants into the literal pools for the module, but it will not check for duplicates. We can do much better by having the compiler use the literal pool for floating point constants. --- erts/emulator/beam/beam_load.c | 5 ++++- lib/compiler/src/beam_asm.erl | 2 +- lib/compiler/src/beam_disasm.erl | 7 ++++++- 3 files changed, 11 insertions(+), 3 deletions(-) diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c index f57fa2bfbb..81c1ea749a 100644 --- a/erts/emulator/beam/beam_load.c +++ b/erts/emulator/beam/beam_load.c @@ -1853,7 +1853,10 @@ load_code(LoaderState* stp) unsigned tag; switch (last_op->a[arg].val) { - case 0: /* Floating point number */ + case 0: + /* Floating point number. + * Not generated by the compiler in R16B and later. + */ { Eterm* hp; /* XXX:PaN - Halfword should use ARCH_64 variant instead */ diff --git a/lib/compiler/src/beam_asm.erl b/lib/compiler/src/beam_asm.erl index a7c8508321..98967e651f 100644 --- a/lib/compiler/src/beam_asm.erl +++ b/lib/compiler/src/beam_asm.erl @@ -387,7 +387,7 @@ encode_arg({list, List}, Dict0) -> {L, Dict} = encode_list(List, Dict0, []), {[encode(?tag_z, 1), encode(?tag_u, length(List))|L], Dict}; encode_arg({float, Float}, Dict) when is_float(Float) -> - {[encode(?tag_z, 0),<>], Dict}; + encode_arg({literal,Float}, Dict); encode_arg({fr,Fr}, Dict) -> {[encode(?tag_z, 2),encode(?tag_u, Fr)], Dict}; encode_arg({field_flags,Flags0}, Dict) -> diff --git a/lib/compiler/src/beam_disasm.erl b/lib/compiler/src/beam_disasm.erl index 62bdc74cc8..67d756c45c 100644 --- a/lib/compiler/src/beam_disasm.erl +++ b/lib/compiler/src/beam_disasm.erl @@ -512,7 +512,12 @@ decode_z_tagged(Tag,B,Bs,Literals) when (B band 16#08) =:= 0 -> decode_alloc_list(Bs, Literals); 4 -> % literal {{u,LitIndex},RestBs} = decode_arg(Bs), - {{literal,gb_trees:get(LitIndex, Literals)},RestBs}; + case gb_trees:get(LitIndex, Literals) of + Float when is_float(Float) -> + {{float,Float},RestBs}; + Literal -> + {{literal,Literal},RestBs} + end; _ -> ?exit({decode_z_tagged,{invalid_extended_tag,N}}) end; -- cgit v1.2.3 From 819894b14db18c98ea0460cbbb28f3ad2a1d1b1b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Mon, 28 Jan 2013 12:16:32 +0100 Subject: beam_type: Convert integer to float at compile time In code such as: X / 2 the following code would be output from beam_type for the division: {fconv,{x,0},{fr,0}}. {fconv,{integer,2},{fr,1}}. fclearerror. {bif,fdiv,{f,0},[{fr,0},{fr,1}],{fr,0}}. That is, the integer 2 would be converted to the float 2.0 at run-time by "{fconv,{integer,2},{fr,1}}". Make sure that we do the conversion at compile time. Noticed-by: Richard O'Keefe --- lib/compiler/src/beam_type.erl | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/lib/compiler/src/beam_type.erl b/lib/compiler/src/beam_type.erl index 7392f99fb6..372923a5cf 100644 --- a/lib/compiler/src/beam_type.erl +++ b/lib/compiler/src/beam_type.erl @@ -142,9 +142,11 @@ simplify_float(Is0, Ts0) -> throw:not_possible -> not_possible end. -simplify_float_1([{set,[D0],[A],{alloc,_,{gc_bif,'-',{f,0}}}}=I|Is]=Is0, Ts0, Rs0, Acc0) -> - case tdb_find(A, Ts0) of +simplify_float_1([{set,[D0],[A0],{alloc,_,{gc_bif,'-',{f,0}}}}=I|Is]=Is0, + Ts0, Rs0, Acc0) -> + case tdb_find(A0, Ts0) of float -> + A = coerce_to_float(A0), {Rs1,Acc1} = load_reg(A, Ts0, Rs0, Acc0), {D,Rs} = find_dest(D0, Rs1), Areg = fetch_reg(A, Rs), @@ -156,13 +158,16 @@ simplify_float_1([{set,[D0],[A],{alloc,_,{gc_bif,'-',{f,0}}}}=I|Is]=Is0, Ts0, Rs {Rs,Acc} = flush(Rs0, Is0, Acc0), simplify_float_1(Is, Ts, Rs, [I|checkerror(Acc)]) end; -simplify_float_1([{set,[D0],[A,B],{alloc,_,{gc_bif,Op0,{f,0}}}}=I|Is]=Is0, Ts0, Rs0, Acc0) -> - case float_op(Op0, A, B, Ts0) of +simplify_float_1([{set,[D0],[A0,B0],{alloc,_,{gc_bif,Op0,{f,0}}}}=I|Is]=Is0, + Ts0, Rs0, Acc0) -> + case float_op(Op0, A0, B0, Ts0) of no -> Ts = update(I, Ts0), {Rs,Acc} = flush(Rs0, Is0, Acc0), simplify_float_1(Is, Ts, Rs, [I|checkerror(Acc)]); {yes,Op} -> + A = coerce_to_float(A0), + B = coerce_to_float(B0), {Rs1,Acc1} = load_reg(A, Ts0, Rs0, Acc0), {Rs2,Acc2} = load_reg(B, Ts0, Rs1, Acc1), {D,Rs} = find_dest(D0, Rs2), @@ -187,6 +192,16 @@ simplify_float_1([], Ts, Rs, Acc0) -> Is = opt_fmoves(Is0, []), {Is,Ts}. +coerce_to_float({integer,I}=Int) -> + try float(I) of + F -> + {float,F} + catch _:_ -> + %% Let the overflow happen at run-time. + Int + end; +coerce_to_float(Other) -> Other. + opt_fmoves([{set,[{x,_}=R],[{fr,_}]=Src,fmove}=I1, {set,[_]=Dst,[{x,_}=R],move}=I2|Is], Acc) -> case beam_utils:is_killed_block(R, Is) of -- cgit v1.2.3