TransformationContext now holds a std::unique_ptr to a FactManager,
rather than a plain pointer. This makes it easier for clients of
TransformationContext to work with heap-allocated instances of
TransformationContext, which is needed in some upcoming work.
Pointer (if VariablePointers is enabled) to find sets of potential
synonyms.
However, some instructions with these types cannot be used in an OpPhi:
- OpFunction cannot be used as a value
- OpUndef should not be used, because it yields an undefined value for
each use
Fixes#3761.
A transformation that adds new OpPhi instructions to blocks with >=1
predecessors, so that its value depends on previously-defined ids of
the right type, which are all synonymous. This instruction is also
recorded as synonymous to the others.
The related fuzzer pass still needs to be implemented.
Fixes#3592 .
