- A LINENUMEBER node is "dead" if the corresponding instruction interval
contains at least one "dead" bytecode instruction
and no live bytecode instructions
- Observable local variable lifetimes should be taken into account
when determining if a NOP is required for debugger.
Remove redundant NOPs during bytecode optimization.
NOP instruction is required iff one of the following is true:
(a) it is a first bytecode instruction in a try-catch block (JVM BE assumption);
(b) it is a sole bytecode instruction in a source code line (breakpoints on that line will not work).
All other NOP instructions can be removed.
Note that it doesn't really affect the performance for mature JVM implementations.
However, the perceived quality of the generated code is somewhat improved :).
Related: KT-15609
POP operations are backward-propagated.
Operation can't be transformed if its result is moved within stack
(by DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, or SWAP).
Unnecessary operations are replaced with NOPs (for debugger).
Unnecessary NOPs are removed.
KT-9922 Suboptimal generation for simple safe call with unused return value
KT-11116 Optimize methods returning Unit
