MSSA-based LICM has been enabled by default for a few years now.
This drops the old AST-based implementation. Using loop(licm) will
result in a fatal error, the use of loop-mssa(licm) is required
(or just licm, which defaults to loop-mssa).
Note that the core canSinkOrHoistInst() logic has to retain AST
support for now, because it is shared with LoopSink.
Differential Revision: https://reviews.llvm.org/D108244
This patch fixes 2 related bugs in ADCE:
- `performDeadCodeElimination` does not report changes if it did ONLY
CFG changes (affects both old and new pass managers);
- When control flow removal is enabled, new pass manager does not
drop CFG analyses.
Both can lead to incorrect loop info after ADCE that does only CFG changes.
Differential Revision: https://reviews.llvm.org/D78103
Reviewed By: Denis Antrushin