| Age | Commit message (Collapse) | Author |
|---|
|
Consider the following code:
bme(Int) ->
TagInt = Int band 2#111,
Tag = case TagInt of
0 -> a; 1 -> b; 2 -> c; 3 -> d;
4 -> e; 5 -> f; 6 -> g; 7 -> h
end,
case Tag of
g -> expects_g(TagInt, Tag);
h -> expects_h(TagInt, Tag);
_ -> Tag = id(Tag), ok
end.
expects_g(6, Atom) -> Atom = id(g), ok.
expects_h(7, Atom) -> Atom = id(h), ok.
The type optimization pass would recognize that TagInt can only be
[0 .. 7], so the first 'case' would select_val over [0 .. 6] and swap
out the fail label with the block for 7.
A later optimization would merge this block with 'expects_h' in the
second case, as the latter is only reachable from the former.
... but this broke down when the move elimination optimization didn't
take the fail label of the first select_val into account. This caused it
believe that the only way to reach 'expects_h' was through the second
case when 'Tag' =:= 'h', which made it remove the move instruction
added in the first case, passing garbage to expects_h/2.
|
|
The previous optimizations caused some code in beam_jump to
become uncovered. Add tests to cover more code. Also remove
a clause in beam_jump:opt/3 that does not seem possible to
cover anymore (this is safe, because the clause was an
optimization).
|
|
* maint:
Fix bug when beam_jump removes put_tuple instructions
Conflicts:
lib/compiler/src/beam_jump.erl
lib/compiler/test/beam_jump_SUITE.erl
|
|
`beam_jump` could remove a `put_tuple` instruction when the
tuple would not be used, but it would leave the following
`put` instructions. Make sure they are removed.
https://bugs.erlang.org/browse/ERL-759
|
|
The `beam_jump` pass could eliminate `move` instructions when it was
not safe to do so. See the new test case `unsafe_move_elimination/1`
for an example.
Reported-by: Michał Muskała
|
|
|
|
Call test_lib:recompile/1 from init_per_suite/1 instead of
from all/0. That makes it easy to find the log from the
compilation in the log file for the init_per_suite/1 test
case.
|
|
It is not safe to share code between 'catch' blocks.
|
|
In complicated code with many indirect jumps to the func_info label,
a label could get lost.
|
