Re: [lno] [PATCH] Loop Versioning

[Devang Patel <dpatel at apple dot com>]

OK this version of patch passes bootstrapped when I enable loop 
versioning
and supply -ftree-loop-optimize through BOOT_FLAGS with one condition 
:-)

And one condition is: I need to disable tree_ssa_iv_optimize().
Combination of iv optimization and loop versioning is exposing some bug.
I am not sure how to fix it.

In iv optimization,

   2797 static void
   2798 create_new_iv (struct iv_cand *cand)
   2799 {
   ...
   2854   if (stmts)
   2855     bsi_insert_on_edge_immediate (loop_preheader_edge 
(current_loop), stmts);
   2856
   2857   stmt = create_phi_node (cand->var_before, 
current_loop->header);
   2858   SSA_NAME_DEF_STMT (cand->var_before) = stmt;
   2859   add_phi_arg (&stmt, initial, loop_preheader_edge 
(current_loop));
   2860   add_phi_arg (&stmt, cand->var_after, loop_latch_edge 
(current_loop));
   2861 }

bsi_insert_on_edge_immediate() at line #2855 may case entry edge split 
using
tree_split_edge(). Which means after that, current_loop's entry edge 
will
have new basic block as its source. Now this basic block's 
'loop_father' is
not set by tree_split_edge() or bsi_insert_on_edge_immediate(). This 
cause
ICE when someone try to check ifthis new bb is in a loop or not (through
flow_bb_inside_loop_p()).

Any ideas how to fix this?

Meanwhile, OK to check-in loop versioning, disabled by default?
Thank you,
--
Devang

2003-01-29  Devang Patel <dpatel@apple.com>

        * cfglayout.h (loopify): Add new bool parameter.
        * cfgloopmanip.c (loopify): Support new bool argument.
        * loop-unswitch.c (unswitch_loop): Supply additional argument 
'true'
        to loopify.
        * tree-cfg.c (tree_block_label): Make externally visible.
        * tree-flow.h (tree_block_label, test_loop_versioning, 
tree_ssa_loop_version): New
        extern decls.
        * tree-ssa-loop-manip.c (lv_adjust_loop_entry_edge, 
lv_udate_pending_stmts,
        lv_adjust_loop_header_phi, tree_ssa_loop_version): New 
functions.
        * tree-ssa-loop.c (tree_ssa_loop_opt): Test loop versioning.

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