On Thu, Feb 14, 2019 at 12:08 AM Aaron Sawdey <acsaw...@linux.ibm.com> wrote: > > I've tracked pr/88308 down to move_insn_for_shrink_wrap(). This function > moves an insn > from one BB to another by copying it and deleting the old one. Unfortunately > this does > the LABEL_NUSES count on labels referenced because deleting the old > instruction decrements > the count and nothing in this function is incrementing the count. > > It just happens that on rs6000 with -m64, force_const_mem() gets called on > the address > and that sets LABEL_PRESERVE_P on the label which prevents it from being > deleted. For > whatever reason this doesn't happen in a -m32 compilation, and the label and > it's associated > jump table data are deleted. This later causes the ICE when the dwarf code > tries to look > at the label. > > Segher and I came up with 3 possible solutions to this: > > 1) Don't let move_insn_for_shrink_wrap try to move insns with label_ref in > them. > 2) Call mark_jump_label() on the copied instruction to fix up the ref counts. > 3) Make the function actually move the insn instead of copying/deleting it. > > It seemed like option 2 was the best thing for stage 4 as it is not > inhibiting anything > and is just doing a fixup of the ref count. > > OK for trunk after regtesting on ppc64be (32/64) and x86_64?
OK. > Thanks! > Aaron > > > 2019-02-13 Aaron Sawdey <acsaw...@linux.ibm.com> > > * shrink-wrap.c (move_insn_for_shrink_wrap): Fix LABEL_NUSES counts > on copied instruction. > > > Index: gcc/shrink-wrap.c > =================================================================== > --- gcc/shrink-wrap.c (revision 268783) > +++ gcc/shrink-wrap.c (working copy) > @@ -414,7 +414,12 @@ > dead_debug_insert_temp (debug, DF_REF_REGNO (def), insn, > DEBUG_TEMP_BEFORE_WITH_VALUE); > > - emit_insn_after (PATTERN (insn), bb_note (bb)); > + rtx_insn *insn_copy = emit_insn_after (PATTERN (insn), bb_note (bb)); > + /* Update the LABEL_NUSES count on any referenced labels. The ideal > + solution here would be to actually move the instruction instead > + of copying/deleting it as this loses some notations on the > + insn. */ > + mark_jump_label (PATTERN (insn), insn_copy, 0); > delete_insn (insn); > return true; > } > > > -- > Aaron Sawdey, Ph.D. acsaw...@linux.vnet.ibm.com > 050-2/C113 (507) 253-7520 home: 507/263-0782 > IBM Linux Technology Center - PPC Toolchain >
