Bottom right: distribution of WD masses for the pre-CVs (solid) and for the fiducial sample of CVs (dashed). Bottom left: comparison between the initial-to-final mass (IFM) of our sample of pre-CVs (crosses) with several proposed IFM relations for single-star evolution (grey lines, from top to bottom: Catalán et al. 2008; Williams et al. 2009; Casewell et al. 2009; and Weidemann 2000) and their average (black dashed line). For WD masses exceeding  ~0.5   M_⊙ the reconstructed initial masses are very close to the average IFM. Top: progenitor-mass distribution for the WDs in pre-CVs (solid) and for the WDs in CVs (dashed). The latter was computed assuming the average IFM relation from the bottom left panel, which gives reasonable results because of the high WD masses in our fiducial CV sample (see the text for details).