FailedChanges

Summary

  1. [Attributor][NFCI] Distinguish optional and required dependences (details)
  2. [Attributor][NFCI] Do not track unnecessary dependences (details)
Commit 680f6380278aa5ce871d912072272b393e53b69d by johannes
[Attributor][NFCI] Distinguish optional and required dependences
Dependences between two abstract attributes SRC and TRG come naturally
in two flavors:
Either (1) "some" information of SRC is *required* for TRG to derive
information, or (2) SRC is just an *optional* way for TRG to derive
information.
While it is not strictly necessary to distinguish these types
explicitly, it can help us to converge faster, in terms of iterations,
and also cut down the number of `AbstractAttribute::update` calls.
As far as I can tell, we only use optional dependences for liveness so
far but that might change in the future. With this change the Attributor
can be informed about the "dependence class" and it will perform
appropriate actions when an Attribute is set to an invalid state, thus
one that cannot be used by others to derive information from.
The file was modifiedllvm/test/Transforms/FunctionAttrs/nonnull.ll
The file was modifiedllvm/test/Transforms/FunctionAttrs/arg_returned.ll
The file was modifiedllvm/test/Transforms/FunctionAttrs/internal-noalias.ll
The file was modifiedllvm/test/Transforms/FunctionAttrs/read_write_returned_arguments_scc.ll
The file was modifiedllvm/include/llvm/Transforms/IPO/Attributor.h
The file was modifiedllvm/lib/Transforms/IPO/Attributor.cpp
The file was modifiedllvm/test/Transforms/FunctionAttrs/nofree-attributor.ll
The file was modifiedllvm/test/Transforms/FunctionAttrs/liveness.ll
The file was modifiedllvm/test/Transforms/FunctionAttrs/align.ll
Commit 77a6b358b51f363d0f1626579720e654ca5aae9a by johannes
[Attributor][NFCI] Do not track unnecessary dependences
If we do not look at assumed information there is no need to track
dependences.
The file was modifiedllvm/lib/Transforms/IPO/Attributor.cpp