Move rewriting of bs_match from beam_clean to beam_z

The actual bs_match_string instruction has four operands:

   bs_match_string {f,Lbl} Ctxt NumBits {string,ListOfBytes}

However, v3_codegen emits a more compact representation where
the bits to match are packaged in a bitstring:

   bs_match_string {f,Lbl} Ctxt Bitstring

Currently, beam_clean:clean_labels/1 will rewrite the compact
representation to the final representation. That is unfortunate
since clean_labels/1 is called by beam_dead, which means that
the less compact representation will be introduced long before
it is actually needed by beam_asm. It will also complicate any
optimizations that we might want to do.

Move the rewriting of bs_match_string from beam_clean:clean_labels/1
to the beam_z pass, which is the last pass executed before
beam_validator and beam_asm.

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/compiler/src/beam_a.erl b/lib/compiler/src/beam_a.erl
index dd7e03dd28..410f598665 100644
--- a/lib/compiler/src/beam_a.erl
+++ b/lib/compiler/src/beam_a.erl
@@ -91,6 +91,10 @@ rename_instr({bs_private_append=I,F,Sz,U,Src,Flags,Dst}) ->
     {bs_init,F,{I,U,Flags},none,[Sz,Src],Dst};
 rename_instr(bs_init_writable=I) ->
     {bs_init,{f,0},I,1,[{x,0}],{x,0}};
+rename_instr({test,Op,F,[Ctx,Bits,{string,Str}]}) ->
+    %% When compiling from a .S file.
+    <<Bs:Bits/bits,_/bits>> = list_to_binary(Str),
+    {test,Op,F,[Ctx,Bs]};
 rename_instr({put_map_assoc,Fail,S,D,R,L}) ->
     {put_map,Fail,assoc,S,D,R,L};
 rename_instr({put_map_exact,Fail,S,D,R,L}) ->