From 3605e00470d8e04710317b88e135e28082ff27d3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Tue, 14 Aug 2012 09:52:51 +0200 Subject: beam_utils: Correct usage calculations for GC BIFs in blocks The usage calculation only looked at the allocation in GC BIFs, not at the source and destination registers. Also, if there is a failure label, make sure that we test whether the register can be used there. --- lib/compiler/src/beam_utils.erl | 44 +++++++++++++++++++++++++++++++---------- 1 file changed, 34 insertions(+), 10 deletions(-) diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl index 3b24cbfaba..7e4a476dab 100644 --- a/lib/compiler/src/beam_utils.erl +++ b/lib/compiler/src/beam_utils.erl @@ -87,7 +87,7 @@ is_killed_at(R, Lbl, D) when is_integer(Lbl) -> %% across branches. is_not_used(R, Is, D) -> - St = #live{bl=fun check_used_block/2,lbl=D,res=gb_trees:empty()}, + St = #live{bl=check_used_block_fun(D),lbl=D,res=gb_trees:empty()}, case check_liveness(R, Is, St) of {killed,_} -> true; {used,_} -> false; @@ -102,7 +102,7 @@ is_not_used(R, Is, D) -> %% across branches. is_not_used_at(R, Lbl, D) -> - St = #live{bl=fun check_used_block/2,lbl=D,res=gb_trees:empty()}, + St = #live{bl=check_used_block_fun(D),lbl=D,res=gb_trees:empty()}, case check_liveness_at(R, Lbl, St) of {killed,_} -> true; {used,_} -> false; @@ -612,26 +612,50 @@ check_killed_block(_, []) -> transparent. %% %% (Unknown instructions will cause an exception.) -check_used_block({x,X}=R, [{set,_,_,{alloc,Live,_}}|Is]) -> +check_used_block_fun(D) -> + fun(R, Is) -> check_used_block(R, Is, D) end. + +check_used_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], D) -> if X >= Live -> killed; - true -> check_used_block(R, Is) + true -> + case member(R, Ss) orelse + is_reg_used_at(R, Op, D) of + true -> used; + false -> + case member(R, Ds) of + true -> killed; + false -> check_used_block(R, Is, D) + end + end end; -check_used_block(R, [{set,Ds,Ss,_Op}|Is]) -> - case member(R, Ss) of +check_used_block(R, [{set,Ds,Ss,Op}|Is], D) -> + case member(R, Ss) orelse + is_reg_used_at(R, Op, D) of true -> used; false -> case member(R, Ds) of true -> killed; - false -> check_used_block(R, Is) + false -> check_used_block(R, Is, D) end end; -check_used_block(R, [{'%live',Live}|Is]) -> +check_used_block(R, [{'%live',Live}|Is], D) -> case R of {x,X} when X >= Live -> killed; - _ -> check_used_block(R, Is) + _ -> check_used_block(R, Is, D) end; -check_used_block(_, []) -> transparent. +check_used_block(_, [], _) -> transparent. + +is_reg_used_at(R, {gc_bif,_,{f,Lbl}}, D) -> + is_reg_used_at_1(R, Lbl, D); +is_reg_used_at(R, {bif,_,{f,Lbl}}, D) -> + is_reg_used_at_1(R, Lbl, D); +is_reg_used_at(_, _, _) -> false. + +is_reg_used_at_1(_, 0, _) -> + false; +is_reg_used_at_1(R, Lbl, D) -> + not is_not_used_at(R, Lbl, D). index_labels_1([{label,Lbl}|Is0], Acc) -> Is = lists:dropwhile(fun({label,_}) -> true; -- cgit v1.2.3