[gcc r13-1387] Make sure checking code is conditional in VN

[Richard Biener <rguenth@gcc.gnu.org>]

https://gcc.gnu.org/g:08ed796ed08996545c574b846f3ca04f2cbe70dc

commit r13-1387-g08ed796ed08996545c574b846f3ca04f2cbe70dc
Author: Richard Biener <rguenther@suse.de>
Date:   Fri Jul 1 12:35:58 2022 +0200

    Make sure checking code is conditional in VN
    
    VN has checking code with gcc_unreachable (), the following makes
    it cheaper by instead guarding the side-effect with flag_checking.
    
    2022-07-01  Richard Biener  <rguenther@suse.de>
    
            * tree-ssa-sccvn.cc (vn_nary_op_insert_into): Make
            checking dominance check conditional on flag_checking.

Diff:
---
 gcc/tree-ssa-sccvn.cc | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc
index 76d92895a3a..c40c45ed840 100644
--- a/gcc/tree-ssa-sccvn.cc
+++ b/gcc/tree-ssa-sccvn.cc
@@ -4243,9 +4243,10 @@ vn_nary_op_insert_into (vn_nary_op_t vno, vn_nary_op_table_type *table)
 		      if (dominated_by_p (CDI_DOMINATORS, vno_bb, val_bb))
 			/* Value registered with more generic predicate.  */
 			return *slot;
-		      else if (dominated_by_p (CDI_DOMINATORS, val_bb, vno_bb))
+		      else if (flag_checking)
 			/* Shouldn't happen, we insert in RPO order.  */
-			gcc_unreachable ();
+			gcc_assert (!dominated_by_p (CDI_DOMINATORS,
+						     val_bb, vno_bb));
 		    }
 		  /* Append value.  */
 		  *next = (vn_pval *) obstack_alloc (&vn_tables_obstack,