> The problem is that in delete_insn, while deleting an undeletable label (in > other words, transforming a label into a INSN_NOTE_DELETED_LABEL): > - we try to find the bb of a NOTE_INSN_BASIC_BLOCK following the label using > BLOCK_FOR_INSN (which is NULL) instead of NOTE_BASIC_BLOCK (which is not > NULL), and > - we don't handle the case that we find a NULL pointer for that bb > gracefully.
Can the NOTE_BASIC_BLOCK of a NOTE_INSN_BASIC_BLOCK really be NULL? > This comment in insn-notes.def tells us that the bb info could be in either > of the two: > ... > /* Record the struct for the following basic block. Uses > NOTE_BASIC_BLOCK. FIXME: Redundant with the basic block pointer > now included in every insn. */ > INSN_NOTE (BASIC_BLOCK) > ... > > The patch fixes the problems by: > - using NOTE_BASIC_BLOCK to find the bb of NOTE_INSN_BASIC_BLOCK, and > - explicitly handling the cases that the bb of either the label or the note > is NULL. I don't think that we need to handle the very last case. > 2013-02-04 Tom de Vries <t...@codesourcery.com> > > PR rtl-optimization/56131 > * cfgrtl.c (delete_insn): Use NOTE_BASIC_BLOCK instead of BLOCK_FOR_INSN > to get the bb of a NOTE_INSN_BASIC_BLOCK. Handle the case that the bb > of the label is NULL. Add comment. OK on principle, but remove the handling of the NULL NOTE_BASIC_BLOCK and keep everything in a single condition. -- Eric Botcazou
