[PATCH] Clear stale entries from int_hash_table

[Richard Biener]

When ggc_free()ing TYPE_MIN/MAX_VALUE in type_hash_canon we have to
make sure to not leave stale entries in int_hash_table.  The following
fixes that and also makes two related changes - freeing a built
INTEGER_CST with a existing entry and properly hashing and finding
redundancies of integer types with max value that doesn't fit into
64bits (any __int128 type).

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Richard.

2017-11-27  Richard Biener  <rguent...@suse.de>

        * tree.c (wide_int_to_tree): Free discarded INTEGER_CST.
        (type_hash_canon): Also clear int_cst_hash_table entry for
        TYPE_MIN/MAX_VALUE.
        (build_nonstandard_integer_type): Hash all TYPE_MAX_VALUEs.

Index: gcc/tree.c
===================================================================
--- gcc/tree.c  (revision 255138)
+++ gcc/tree.c  (working copy)
@@ -1576,6 +1576,8 @@ wide_int_to_tree (tree type, const wide_
          t = nt;
          *slot = t;
        }
+      else
+       ggc_free (nt);
     }
 
   return t;
@@ -6496,10 +6502,18 @@ type_hash_canon (unsigned int hashcode,
        {
          if (TYPE_MIN_VALUE (type)
              && TREE_TYPE (TYPE_MIN_VALUE (type)) == type)
-           ggc_free (TYPE_MIN_VALUE (type));
+           {
+             /* Zero is always in TYPE_CACHED_VALUES.  */
+             if (! TYPE_UNSIGNED (type))
+               int_cst_hash_table->remove_elt (TYPE_MIN_VALUE (type));
+             ggc_free (TYPE_MIN_VALUE (type));
+           }
          if (TYPE_MAX_VALUE (type)
              && TREE_TYPE (TYPE_MAX_VALUE (type)) == type)
-           ggc_free (TYPE_MAX_VALUE (type));
+           {
+             int_cst_hash_table->remove_elt (TYPE_MAX_VALUE (type));
+             ggc_free (TYPE_MAX_VALUE (type));
+           }
          if (TYPE_CACHED_VALUES_P (type))
            ggc_free (TYPE_CACHED_VALUES (type));
        }
@@ -7486,8 +7500,10 @@ build_nonstandard_integer_type (unsigned
     fixup_signed_type (itype);
 
   ret = itype;
-  if (tree_fits_uhwi_p (TYPE_MAX_VALUE (itype)))
-    ret = type_hash_canon (tree_to_uhwi (TYPE_MAX_VALUE (itype)), itype);
+
+  inchash::hash hstate;
+  inchash::add_expr (TYPE_MAX_VALUE (itype), hstate);
+  ret = type_hash_canon (hstate.end (), itype);
   if (precision <= MAX_INT_CACHED_PREC)
     nonstandard_integer_type_cache[precision + unsignedp] = ret;