Hi!
Thanks for working on this.
On Wed, Jan 16, 2019 at 10:20:26AM -0500, David Malcolm wrote:
> PR target/88861 reports an ICE in "ce2" due to an unreachable
> basic block.
>
> The block becomes unreachable in "combine" when delete_noop_moves
> deletes an insn with a REG_EH_REGION, deleting the EH edge, the
> only edge leading to the basic block.
>
> Normally, rest_of_handle_combine would call cleanup_cfg, deleting
> unreachable blocks, if combine_instructions returns true, and
> combine_instructions does return true for some cases of edge-removal,
> but it doesn't for this case, leading to the ICE.
>
> This patch updates delete_noop_moves so that it returns true if
> it deletes any edges, and passes that through to combine_instructions,
> so that it too will return true if any edges were deleted, ensuring that
> cleanup_cfg will be called by rest_of_handle_combine for this case,
> deleting the now-unreachable block, and fixing the ICE.
> -/* Delete any insns that copy a register to itself. */
> +/* Delete any insns that copy a register to itself.
> + Return true if any edges are eliminated. */
"if the CFG was changed" or similar text?
> -static void
> +static bool
> delete_noop_moves (void)
> {
> rtx_insn *insn, *next;
> basic_block bb;
>
> + bool edges_deleted = false;
> +
> FOR_EACH_BB_FN (bb, cfun)
> {
> for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); insn = next)
> @@ -1001,10 +1004,11 @@ delete_noop_moves (void)
> if (dump_file)
> fprintf (dump_file, "deleting noop move %d\n", INSN_UID (insn));
>
> - delete_insn_and_edges (insn);
> + edges_deleted |= delete_insn_and_edges (insn);
> }
> }
> }
Empty line here, too, please.
> + return edges_deleted;
> }
> /* Main entry point for combiner. F is the first insn of the function.
> NREGS is the first unused pseudo-reg number.
>
> - Return nonzero if the combiner has turned an indirect jump
> - instruction into a direct jump. */
> + Return nonzero if any edges have been removed (e.g. if the combiner has
> + turned an indirect jump instruction into a direct jump). */
"if the CFG was changed", again.
> static int
> combine_instructions (rtx_insn *f, unsigned int nregs)
Okay with that. Thanks!
Segher
