Before this commit, the AvailableExpressionAnalysis used by
SwitchToStatements did not take into account the full set of custom
opcodes that allocate local variables.
In particular, if only checked FunctionTags::LocalVariable, and not the
larger set marked with the tag FunctionTags::AllocatesLocalVariable,
which includes revng_stack_frame and revng_call_stack_arguments.
This caused all the reasoning on aliasing that involved the stack to be
broken.
This commit fixes the problem by properly using the
FunctionTags::AllocatesLocalVariable to reason about aliasing.
Before this commit, the InstructionToSerializePicker had a wrong bailout
condition, that caused to never pick for serialization memory reads.
This was wrong and caused semantic bugs, due to the instruction
performing the memory read not being serialized into a new variable.
Pietro Fezzardi