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| author | Björn Gustavsson <[email protected]> | 2016-04-05 12:56:57 +0200 |
|---|---|---|
| committer | Björn Gustavsson <[email protected]> | 2016-04-07 15:28:29 +0200 |
| commit | 937f527054f13dd524588c064cd5d76e3cfd23eb (patch) | |
| tree | 8fe284d496399fb4b0a3e07286b101517dbf4f6a /erts/emulator/beam/beam_load.c | |
| parent | e93a66110aa27a5b8228fb46a3459a6de0e626d0 (diff) | |
| download | otp-937f527054f13dd524588c064cd5d76e3cfd23eb.tar.gz otp-937f527054f13dd524588c064cd5d76e3cfd23eb.tar.bz2 otp-937f527054f13dd524588c064cd5d76e3cfd23eb.zip | |
Avoid rebuilding unchanged instructions
In transformations such as:
move S X0=x==0 | line Loc | call_ext Ar Func => \
line Loc | move S X0 | call_ext Ar Func
we can avoid rebuilding the last instruction in the sequence
by introducing a 'keep' instruction.
Currently, there are only 13 transformations that are hit by
this optimization, but most of them are frequently used.
Diffstat (limited to 'erts/emulator/beam/beam_load.c')
| -rw-r--r-- | erts/emulator/beam/beam_load.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c index ad174664ae..bdb451a6fe 100644 --- a/erts/emulator/beam/beam_load.c +++ b/erts/emulator/beam/beam_load.c @@ -5028,7 +5028,16 @@ transform_engine(LoaderState* st) instr = 0; #endif break; - +#if defined(TOP_keep) + case TOP_keep: + /* Keep the current instruction unchanged. */ + keep = instr; + st->genop = instr; +#ifdef DEBUG + instr = 0; +#endif + break; +#endif #if defined(TOP_call_end) case TOP_call_end: { |