[RFA][PATCH] Don't use wi->info to pass gimple location to array warning callbacks in tree-vrp.c

[Jeff Law]

The array dereference warnings in tree-vrp.c use the gimple walkers to
dig down into gimple statements looking for array accesses.  I wasn't
keen to convert all the clients of the gimple walkers to C++ classes at
this time.

And the gimple walkers have a mechanism by which we could pass around a
class instance -- they've got an opaque pointer (wi->info).

THe pointer is already in use to hold a gimple location.  So I initially
thought I'd have to instead have it point to a structure that would hold
the gimple location and a class instance.

However, we can get to the gimple location via other means -- we can
just extract it from the gimple statement which is a first class entity
within the wi structure.  That's all this patch does.


That frees up the opaque pointer and in a future patch I can just shove
the vr_values class instance into it.

Bootstrapped and regression tested on x86_64.

OK for the trunk?

Jeff

ps.  Now to figure out a strategy for vrp_valueize, which are the last
callbacks that need fixing to allow encapsulation of the vr_values bits.

        * tree-vrp.c (check_all_array_refs): Do not use wi->info to smuggle
        gimple statement locations.
        (check_array_bounds): Corresponding changes.  Get the statement's
        location directly from wi->stmt.


diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 2bc485c..9defbce 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -6837,10 +6837,7 @@ check_array_bounds (tree *tp, int *walk_subtree, void 
*data)
   if (EXPR_HAS_LOCATION (t))
     location = EXPR_LOCATION (t);
   else
-    {
-      location_t *locp = (location_t *) wi->info;
-      location = *locp;
-    }
+    location = gimple_location (wi->stmt);
 
   *walk_subtree = TRUE;
 
@@ -6887,9 +6884,6 @@ check_all_array_refs (void)
 
          memset (&wi, 0, sizeof (wi));
 
-         location_t loc = gimple_location (stmt);
-         wi.info = &loc;
-
          walk_gimple_op (gsi_stmt (si),
                          check_array_bounds,
                          &wi);