Build a GIMPLE_RESX statement which is a statement. This
statement is a placeholder for _Unwind_Resume before we know if a
function call or a branch is needed. REGION is the exception
region from which control is flowing.
— GIMPLE function: int gimple_resx_region (const gresx *g)
Return the region number for GIMPLE_RESXG.
— GIMPLE function: void gimple_resx_set_region (gresx *g, int region)
Set REGION to be the region number for GIMPLE_RESXG.