https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85168
Ivo Raisr <ivo.raisr at oracle dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |ivo.raisr at oracle dot com --- Comment #1 from Ivo Raisr <ivo.raisr at oracle dot com> --- Debug output for rtl-expand shows: ... Partition map Partition 0 (h_5(ab) - 5 ) Partition 1 (h_6(ab) - 6 ) Partition 2 (h_7 - 7 ) Partition 3 (h_12(ab) - 12 ) Partition 4 (h_14(ab) - 14 ) Partition 5 (h_20 - 20 ) Partition 6 (pretmp_21 - 21 ) Partition 7 (pretmp_22 - 22 ) Partition 8 (pretmp_23 - 23 ) Partition 9 (prephitmp_24 - 24 ) Conflict graph: 3: 4 4: 3 ... Abnormal coalesce: (6)h_6(ab) & (12)h_12(ab) [map: 1, 3] : Success -> 1 Abnormal coalesce: (6)h_6(ab) & (14)h_14(ab) [map: 1, 4] : Fail due to conflict I am not sure if the conflict is because h_12 and h_14 are still live at the same time or that h_7 and h_20 are not marked abnormal.