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authorBjörn Gustavsson <[email protected]>2018-01-25 10:09:59 +0100
committerBjörn Gustavsson <[email protected]>2018-01-26 15:57:57 +0100
commitfbcff5a137e37edd80aca9c5fe18ce6880648169 (patch)
treefb846d82599a3e52230f1b028b59f63cb0dd09ec /lib/hipe/icode
parent5b58d9e2d3262160b7f10d8b6798f89f0618c5f6 (diff)
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Eliminate get_list/3 internally in the compiler
Instructions that produce more than one result complicate optimizations. get_list/3 is one of two instructions that produce multiple results (get_map_elements/3 is the other). Introduce the get_hd/2 and get_tl/2 instructions that return the head and tail of a cons cell, respectively, and use it internally in all optimization passes. For efficiency, we still want to use get_list/3 if both head and tail are used, so we will translate matching pairs of get_hd and get_tl back to get_list instructions.
Diffstat (limited to 'lib/hipe/icode')
-rw-r--r--lib/hipe/icode/hipe_beam_to_icode.erl10
1 files changed, 10 insertions, 0 deletions
diff --git a/lib/hipe/icode/hipe_beam_to_icode.erl b/lib/hipe/icode/hipe_beam_to_icode.erl
index 6e66ec057c..f429d40272 100644
--- a/lib/hipe/icode/hipe_beam_to_icode.erl
+++ b/lib/hipe/icode/hipe_beam_to_icode.erl
@@ -605,6 +605,16 @@ trans_fun([{get_list,List,Head,Tail}|Instructions], Env) ->
?error_msg("hd and tl regs identical in get_list~n",[]),
erlang:error(not_handled)
end;
+%%--- get_hd ---
+trans_fun([{get_hd,List,Head}|Instructions], Env) ->
+ TransList = [trans_arg(List)],
+ I = hipe_icode:mk_primop([mk_var(Head)],unsafe_hd,TransList),
+ [I | trans_fun(Instructions,Env)];
+%%--- get_tl ---
+trans_fun([{get_tl,List,Tail}|Instructions], Env) ->
+ TransList = [trans_arg(List)],
+ I = hipe_icode:mk_primop([mk_var(Tail)],unsafe_tl,TransList),
+ [I | trans_fun(Instructions,Env)];
%%--- get_tuple_element ---
trans_fun([{get_tuple_element,Xreg,Index,Dst}|Instructions], Env) ->
I = hipe_icode:mk_primop([mk_var(Dst)],