Questions on verification function df_lr_verify_solution_start/end

[Bin.Cheng]

Hi,
When calculating the DF_LR information, GCC uses
df_lr_verify_solution_start/end to verify the results. The two
functions are called in df_analyze_problem when ENABLE_DF_CHECKING is
defined, with each before and after the analysis. What I don't
understand are:
1. In df_lr_verify_solution_start, it initializes problem_data->in/out
with DF_LR_IN/OUT(bb), but how could it uses DF_LR_IN/OUT before
calculated?
2. In df_lr_verify_solution_end, it verifies problem_data->in/out
against DF_LR_IN/OUT(bb), but I can't find any code calculating
problem_data->in/out except the function df_lr_verify_solution_start.

Any directions? Thanks very much.

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Best Regards.