Age | Commit message (Collapse) | Author |
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Do the optimizations of bs_put* instructions in beam_ssa_opt
and remove the beam_bs pass. This can lead to a slight improvement
of compilation times.
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There are two instructions that take string operands:
{bs_put_string,Fail,NumberOfBytes,{string,String}}
{bs_match_string,Fail,Register,NumberOfBits,{string,String}}
In the canonical BEAM code that is passed to beam_asm, string String
is currently represented as a list. (The string in bs_match_string is
a bitstring before the beam_z compiler pass.) That is wasteful,
because there will be unnecessary conversions between lists and
binaries.
Change the representation of String to be a binary.
Furthermore, bs_put_string is an optimization of a bs_put_binary
instruction with a literal binary operand. Currently, the
bs_put_string instruction is introduced in beam_bs. Delay the
introduction of bs_put_string to the beam_z pass. That will simplify
optimizations and allow us to do the optimization currently done
in beam_bs in a SSA pass in a future commit.
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The optimization can be applied in a few more places if done
before ssa_opt_bsm_shortcut (for example, in unicode:cbv/2).
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The removal of redundant bs_restore2 instructions is done easier
on the SSA format. Keep the rest of the optimizations, because
they are easier to do on the BEAM instructions.
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In the future we might want to add more bit syntax optimizations,
but beam_block is already sufficiently complicated. Therefore, move
the bit syntax optimizations out of beam_block into a separate
compiler pass called beam_bs.
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