[gcc r12-4773] Reset scev before invoking array_checker.

[gcc r12-4773] Reset scev before invoking array_checker.

[Andrew Macleod]

https://gcc.gnu.org/g:d46aeb5906b8ed7ee255cfbacc5cf9d2f56b850c

commit r12-4773-gd46aeb5906b8ed7ee255cfbacc5cf9d2f56b850c
Author: Andrew MacLeod <amacleod@redhat.com>
Date:   Tue Oct 26 14:43:33 2021 -0400

    Reset scev before invoking array_checker.
    
    Before invoking the array_checker, we need to reset scev so it will not try to
    access any ssa_names that the substitute and fold engine has freed.
    
            PR tree-optimization/102940
            * tree-vrp.c (execute_ranger_vrp): Reset scev.

Diff:
---
 gcc/tree-vrp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 38ea50303e0..dc3e250537a 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -4351,7 +4351,6 @@ execute_ranger_vrp (struct function *fun, bool warn_array_bounds_p)
   if (dump_file && (dump_flags & TDF_DETAILS))
     ranger->dump (dump_file);
 
-
   if (warn_array_bounds && warn_array_bounds_p)
     {
       // Set all edges as executable, except those ranger says aren't.
@@ -4367,6 +4366,7 @@ execute_ranger_vrp (struct function *fun, bool warn_array_bounds_p)
 	    else
 	      e->flags |= EDGE_EXECUTABLE;
 	}
+      scev_reset ();
       array_bounds_checker array_checker (fun, ranger);
       array_checker.check ();
     }