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| author | Björn Gustavsson <[email protected]> | 2018-08-24 14:14:09 +0200 |
|---|---|---|
| committer | Björn Gustavsson <[email protected]> | 2018-09-12 14:19:05 +0200 |
| commit | 52abce861178bbce0dc3acb22cc8935f9a434981 (patch) | |
| tree | 3e6be6f21ffc06783f8dada3bc5bb6e50ca04ca7 /lib/compiler/src/beam_a.erl | |
| parent | ecbe1327a5da4ecc02cdbc636bd54d901b92c215 (diff) | |
| download | otp-52abce861178bbce0dc3acb22cc8935f9a434981.tar.gz otp-52abce861178bbce0dc3acb22cc8935f9a434981.tar.bz2 otp-52abce861178bbce0dc3acb22cc8935f9a434981.zip | |
Move two optimizations from beam_dead to beam_a
The 'move' instruction can be eliminated in code such as:
{test,is_eq_exact,{f,42},[{x,0},{atom,value}]}.
{move,{atom,value},{x,0}}.
Move that optimization from beam_dead to beam_a. The optimization
will be simpler because the 'move' instruction has not yet
been moved into a block. Getting rid of 'move' earlier will
also save work for later passes.
Also move the optimization that eliminates instructions such
as from beam_dead to beam_a:
{test_is_eq_exact,{f,42},[{x,0},{x,0}]}.
Diffstat (limited to 'lib/compiler/src/beam_a.erl')
| -rw-r--r-- | lib/compiler/src/beam_a.erl | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/lib/compiler/src/beam_a.erl b/lib/compiler/src/beam_a.erl index 266e8f46c8..0abc845310 100644 --- a/lib/compiler/src/beam_a.erl +++ b/lib/compiler/src/beam_a.erl @@ -52,6 +52,13 @@ function({function,Name,Arity,CLabel,Is0}) -> erlang:raise(Class, Error, Stack) end. +rename_instrs([{test,is_eq_exact,_,[Dst,Src]}=Test, + {move,Src,Dst}|Is]) -> + %% The move instruction is not needed. + rename_instrs([Test|Is]); +rename_instrs([{test,is_eq_exact,_,[Same,Same]}|Is]) -> + %% Same literal or same register. Will always succeed. + rename_instrs(Is); rename_instrs([{apply_last,A,N}|Is]) -> [{apply,A},{deallocate,N},return|rename_instrs(Is)]; rename_instrs([{call_last,A,F,N}|Is]) -> |