[PATCH] passes: Move cleanup_eh before first tailr [PR115201]

[Andrew Pinski]

So the current pass order is:
```
          NEXT_PASS (pass_tail_recursion);
          NEXT_PASS (pass_if_to_switch);
          NEXT_PASS (pass_convert_switch);
          NEXT_PASS (pass_cleanup_eh);
```
But nothing in if_to_switch nor convert_switch will change the IR
such that cleanup eh will take into account.
tail_recusion benifits the most by not having "almost" empty landing pads.
This order was originally done when cleanup_eh was added in 
r0-92178-ga8da523f8a442f
but it looks like it was just done just before inlining rather than thinking it
could improve passes before hand.

An example where this helps is PR 115201 where we have:
```
;;   basic block 5, loop depth 0, maybe hot
;;    prev block 4, next block 6, flags: (NEW, REACHABLE, VISITED)
;;    pred:       4 (TRUE_VALUE,EXECUTABLE)
  [LP 1] # .MEM_19 = VDEF <.MEM_45>
  # USE = nonlocal escaped
  # CLB = nonlocal escaped
  D.4770 = _Z12binarySearchIi2itIiEET0_RKT_S2_S2_D.4690 (item_15(D), 
startD.4711, midD.4717);
  goto <bb 7>; [INV]
;;    succ:       8 (EH,EXECUTABLE)
;;                7 (FALLTHRU,EXECUTABLE)
...

;;   basic block 8, loop depth 0, maybe hot
;;    prev block 7, next block 1, flags: (NEW, REACHABLE, VISITED)
;;    pred:       5 (EH,EXECUTABLE)
;;                6 (EH,EXECUTABLE)
  # .MEM_7 = PHI <.MEM_19(5), .MEM_18(6)>
<L6>: [LP 1]
  # .MEM_20 = VDEF <.MEM_7>
  midD.4717 ={v} {CLOBBER(eos)};
  resx 1
;;    succ:
```

As you can see the empty landing pad should be able to remove away and
then a tail recursion can happen.

Bootstrapped and tested x86_64-linux-gnu.

        PR tree-optimization/115201
gcc/ChangeLog:

        * passes.def: Move cleanup_eh before first tail_recursion.

Signed-off-by: Andrew Pinski <andrew.pin...@oss.qualcomm.com>
---
 gcc/passes.def | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/passes.def b/gcc/passes.def
index 68ce53baa0f..6349abb5360 100644
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -97,10 +97,10 @@ along with GCC; see the file COPYING3.  If not see
           NEXT_PASS (pass_dse);
          NEXT_PASS (pass_cd_dce, false /* update_address_taken_p */, true /* 
remove_unused_locals */);
          NEXT_PASS (pass_phiopt, true /* early_p */);
+         NEXT_PASS (pass_cleanup_eh);
          NEXT_PASS (pass_tail_recursion);
          NEXT_PASS (pass_if_to_switch);
          NEXT_PASS (pass_convert_switch);
-         NEXT_PASS (pass_cleanup_eh);
          NEXT_PASS (pass_sccopy);
          NEXT_PASS (pass_profile);
          NEXT_PASS (pass_local_pure_const);
-- 
2.43.0