Some of the type checking that should be done:
- TREE_TYPE(TREE_TYPE( "COMPLEX_CST" ) ) == TREE_TYPE (TREE_REALPART( "COMPLEX_CST" ) )
- Likewise for TREE_IMAGPART
- Likewise for VECTOR_CST/TREE_VECTOR_CST_ELTS.
- TREE_TYPE (TREE_OPERAND ( "MODIFY_EXPR", 0) )) == TREE_TYPE (TREE_OPERAND ( "MODIFY_EXPR", 1) ))
- TREE_TYPE (LHS OF PHI) == TREE_TYPE (RHS's OF PHI)