Change hash_table to support a comparator type different from the value type stored in the hash table.

Change hash_table to support a comparator type different from the
value type stored in the hash table.  The 'find' functions now may
take a different type from the value type.  This requires introducing
a second typedef into the Descriptor conceptual type.  Change the
Descriptor concept to use typedefs value_type and compare_type instead
of T.  Change all users to match.

Add usage documentation to hash-table.h.

Tested on x86-64.


Index: gcc/ChangeLog

2012-10-25  Lawrence Crowl  <crowl@google.com>

	* hash-table.h: Add usage documentation.
	(template struct typed_free_remove): Clarify documentation. 
	Rename template parameter.
	(struct typed_noop_remove): Likewise.
	(descriptor concept): Change typedef T to value_type.
	Add typedef compare_type.  Use more precise template parameter name,
	Descriptor instead of Descr.  Update users to match.
	(struct hash_table): Change 'find' parameters to use compare_type
	instead of the value type.

From-SVN: r192823

1 files changed, 7 insertions, 5 deletions

diff --git a/gcc/dse.c b/gcc/dse.c
index 631a1f2..3ae8353 100644
--- a/gcc/dse.c
+++ b/gcc/dse.c
@@ -654,19 +654,21 @@ clear_alias_set_lookup (alias_set_type alias_set)
 
 struct invariant_group_base_hasher : typed_noop_remove <group_info>
 {
-  typedef group_info T;
-  static inline hashval_t hash (const T *);
-  static inline bool equal (const T *, const T *);
+  typedef group_info value_type;
+  typedef group_info compare_type;
+  static inline hashval_t hash (const value_type *);
+  static inline bool equal (const value_type *, const compare_type *);
 };
 
 inline bool
-invariant_group_base_hasher::equal (const T *gi1, const T *gi2)
+invariant_group_base_hasher::equal (const value_type *gi1,
+				    const compare_type *gi2)
 {
   return rtx_equal_p (gi1->rtx_base, gi2->rtx_base);
 }
 
 inline hashval_t
-invariant_group_base_hasher::hash (const T *gi)
+invariant_group_base_hasher::hash (const value_type *gi)
 {
   int do_not_record;
   return hash_rtx (gi->rtx_base, Pmode, &do_not_record, NULL, false);