OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Optimise hash_table::empty 

Calling redirect_edge_var_map_empty after each pass was slowing things
down because hash_table::empty () cleared all slots even if the hash
table was already empty.

Tested on x86_64-linux-gnu, where it gives a 1% compile time improvement
for fold-const.ii at -O and -O2.

gcc/
	* hash-table.h (hash_table::empty): Turn into an inline wrapper
	that checks whether the table is already empty.  Rename the
	original implementation to...
	(hash_table::empty_slot): ...this new private function.

From-SVN: r232467
This commit is contained in:
Richard Sandiford 2016-01-16 11:03:18 +00:00 committed by Richard Sandiford
parent b62df3bfc5
commit 677cb11df0
2 changed files with 14 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
gcc/ChangeLog
View File

@ -1,3 +1,10 @@
2016-01-16 Richard Sandiford <richard.sandiford@arm.com>
* hash-table.h (hash_table::empty): Turn into an inline wrapper
that checks whether the table is already empty. Rename the
original implementation to...
(hash_table::empty_slot): ...this new private function.
2016-01-15 David Malcolm <dmalcolm@redhat.com>
PR diagnostic/68899

10
gcc/hash-table.h
View File

@ -390,8 +390,8 @@ public:
/* Return the current number of elements in this hash table. */
size_t elements_with_deleted () const { return m_n_elements; }
/* This function clears all entries in the given hash table. */
void empty ();
/* This function clears all entries in this hash table. */
void empty () { if (elements ()) empty_slow (); }
/* This function clears a specified SLOT in a hash table. It is
useful when you've already done the lookup and don't want to do it
@ -499,6 +499,8 @@ private:
template<typename T> friend void gt_cleare_cache (hash_table<T> *);
void empty_slow ();
value_type *alloc_entries (size_t n CXX_MEM_STAT_INFO) const;
value_type *find_empty_slot_for_expand (hashval_t);
void expand ();
@ -755,9 +757,11 @@ hash_table<Descriptor, Allocator>::expand ()
ggc_free (oentries);
}
/* Implements empty() in cases where it isn't a no-op. */
template<typename Descriptor, template<typename Type> class Allocator>
void
hash_table<Descriptor, Allocator>::empty ()
hash_table<Descriptor, Allocator>::empty_slow ()
{
size_t size = m_size;
value_type *entries = m_entries;