Re: [PATCH] Remove class cache_map and use ggc hash_maps instead (PR c++/70452)

[Jason Merrill]

On 04/04/2016 01:08 PM, Patrick Palka wrote:
+  tree *slot = &cv_cache->get_or_insert (t, NULL);
+  if (*slot == NULL_TREE)
+    *slot = maybe_constant_value_1 (t, decl);
...
-  fold_cache.put (org_x, x);
+  *slot = x;

This pattern isn't safe; the slot might move due to hash table resizing 
between the get_or_insert and the store to *slot.  Just use get/put.

Jason