https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83391
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Jakub Jelinek from comment #6) > The bb is split in: > #0 gsi_split_seq_before (i=0x7fffffffd940, pnew_seq=0x7fffffffd918) at > ../../gcc/gimple-iterator.c:415 > #1 0x00000000011fc89d in gimple_split_block (bb=<basic_block 0x7fffefacb888 > (9)>, stmt=0x0) at ../../gcc/tree-cfg.c:6130 > #2 0x0000000000bf2f15 in split_block_1 (bb=<basic_block 0x7fffefacb888 > (9)>, i=0x0) at ../../gcc/cfghooks.c:520 > #3 0x0000000000bf30d4 in split_block_after_labels (bb=<basic_block > 0x7fffefacb888 (9)>) at ../../gcc/cfghooks.c:572 > #4 0x0000000000bf3aa7 in make_forwarder_block (bb=<basic_block > 0x7fffefacb888 (9)>, redirect_edge_p=0xc0438c <mfb_keep_just(edge_def*)>, > new_bb_cbk=0x0) at ../../gcc/cfghooks.c:875 > #5 0x0000000000c0462b in create_preheader (loop=0x7fffefc20330, flags=1) at > ../../gcc/cfgloopmanip.c:1501 > #6 0x0000000000c04788 in create_preheaders (flags=1) at > ../../gcc/cfgloopmanip.c:1552 > #7 0x0000000000f6dab6 in apply_loop_flags (flags=3) at > ../../gcc/loop-init.c:64 > #8 0x0000000000f6dbf4 in loop_optimizer_init (flags=3) at > ../../gcc/loop-init.c:123 > > Do we really need to allow debug stmts before labels? Pleeeease not. > If yes, I have a fix for gimple_make_forwarder_block.