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| author | Björn Gustavsson <[email protected]> | 2017-06-07 14:27:15 +0200 |
|---|---|---|
| committer | Björn Gustavsson <[email protected]> | 2017-06-07 16:32:35 +0200 |
| commit | 09112806c15a81be86730503af36e304ac11d1ed (patch) | |
| tree | 8f66b637b02762737f4e91bd7077428c736fed0e /lib/compiler/src/compiler.app.src | |
| parent | 1ee59088c52ff18e3917d7f453a5947d0fe1cadd (diff) | |
| download | otp-09112806c15a81be86730503af36e304ac11d1ed.tar.gz otp-09112806c15a81be86730503af36e304ac11d1ed.tar.bz2 otp-09112806c15a81be86730503af36e304ac11d1ed.zip | |
Fix unsafe bit syntax matching optimization
As part of sys_core_fold, variables involved in bit syntax
matching would be annotated when it would be safe for a later
pass to do the delayed sub-binary creation optimization.
An implicit assumption regarding the annotation was that the
code must not be further optimized. That assumption was broken
in 05130e48555891, which introduced a fixpoint iteration
(applying the optimizations until there were no more changes).
That means that a variable could be annotated as safe for
reusing the match context in one iteration, but a later iteration
could rewrite the code in a way that would make the optimization
unsafe.
One way to fix this would be to clear all reuse_for_context
annotations before each iteration. But that would be wasteful.
Instead I chose to fix the problem by moving out the annotation
code to a separate pass (sys_core_bsm) that is run later after
all major optimizations of Core Erlang has been done.
Diffstat (limited to 'lib/compiler/src/compiler.app.src')
| -rw-r--r-- | lib/compiler/src/compiler.app.src | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/lib/compiler/src/compiler.app.src b/lib/compiler/src/compiler.app.src index 3961b2af86..d4b4d4da04 100644 --- a/lib/compiler/src/compiler.app.src +++ b/lib/compiler/src/compiler.app.src @@ -58,6 +58,7 @@ core_lib, erl_bifs, rec_env, + sys_core_bsm, sys_core_dsetel, sys_core_fold, sys_core_fold_lists, |