re PR tree-optimization/46590 (long compile time with -O2 and many loops)

2014-01-17  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/46590
	* vec.h (vec<>::bseach): New member function implementing
	binary search according to C89 bsearch.
	(vec<>::qsort): Avoid calling ::qsort for vectors with sizes 0 or 1.
	* tree-ssa-loop-im.c (struct mem_ref): Make stored member a
	bitmap pointer again.  Make accesses_in_loop a flat array.
	(mem_ref_obstack): New global.
	(outermost_indep_loop): Adjust for mem_ref->stored changes.
	(mark_ref_stored): Likewise.
	(ref_indep_loop_p_2): Likewise.
	(set_ref_stored_in_loop): New helper function.
	(mem_ref_alloc): Allocate mem_refs on the mem_ref_obstack obstack.
	(memref_free): Adjust.
	(record_mem_ref_loc): Simplify.
	(gather_mem_refs_stmt): Adjust.
	(sort_locs_in_loop_postorder_cmp): New function.
	(analyze_memory_references): Sort accesses_in_loop after
	loop postorder number.
	(find_ref_loc_in_loop_cmp): New function.
	(for_all_locs_in_loop): Find relevant cluster of locs in
	accesses_in_loop and iterate without recursion.
	(execute_sm): Avoid uninit warning.
	(struct ref_always_accessed): Simplify.
	(ref_always_accessed::operator ()): Likewise.
	(ref_always_accessed_p): Likewise.
	(tree_ssa_lim_initialize): Initialize mem_ref_obstack, compute
	loop postorder numbers here.
	(tree_ssa_lim_finalize): Free mem_ref_obstack and loop postorder
	numbers.

From-SVN: r206709

1 files changed, 53 insertions, 1 deletions

diff --git a/gcc/vec.h b/gcc/vec.h
index 5d148f9..4e8e3b8 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -476,6 +476,7 @@ public:
   void unordered_remove (unsigned);
   void block_remove (unsigned, unsigned);
   void qsort (int (*) (const void *, const void *));
+  T *bsearch (const void *key, int (*compar)(const void *, const void *));
   unsigned lower_bound (T, bool (*)(const T &, const T &)) const;
   static size_t embedded_size (unsigned);
   void embedded_init (unsigned, unsigned = 0);
@@ -938,7 +939,43 @@ template<typename T, typename A>
 inline void
 vec<T, A, vl_embed>::qsort (int (*cmp) (const void *, const void *))
 {
-  ::qsort (address (), length (), sizeof (T), cmp);
+  if (length () > 1)
+    ::qsort (address (), length (), sizeof (T), cmp);
+}
+
+
+/* Search the contents of the sorted vector with a binary search.
+   CMP is the comparison function to pass to bsearch.  */
+
+template<typename T, typename A>
+inline T *
+vec<T, A, vl_embed>::bsearch (const void *key,
+			      int (*compar) (const void *, const void *))
+{
+  const void *base = this->address ();
+  size_t nmemb = this->length ();
+  size_t size = sizeof (T);
+  /* The following is a copy of glibc stdlib-bsearch.h.  */
+  size_t l, u, idx;
+  const void *p;
+  int comparison;
+
+  l = 0;
+  u = nmemb;
+  while (l < u)
+    {
+      idx = (l + u) / 2;
+      p = (const void *) (((const char *) base) + (idx * size));
+      comparison = (*compar) (key, p);
+      if (comparison < 0)
+	u = idx;
+      else if (comparison > 0)
+	l = idx + 1;
+      else
+	return (T *)const_cast<void *>(p);
+    }
+
+  return NULL;
 }
 
 
@@ -1174,6 +1211,7 @@ public:
   void unordered_remove (unsigned);
   void block_remove (unsigned, unsigned);
   void qsort (int (*) (const void *, const void *));
+  T *bsearch (const void *key, int (*compar)(const void *, const void *));
   unsigned lower_bound (T, bool (*)(const T &, const T &)) const;
 
   bool using_auto_storage () const;
@@ -1635,6 +1673,20 @@ vec<T, va_heap, vl_ptr>::qsort (int (*cmp) (const void *, const void *))
 }
 
 
+/* Search the contents of the sorted vector with a binary search.
+   CMP is the comparison function to pass to bsearch.  */
+
+template<typename T>
+inline T *
+vec<T, va_heap, vl_ptr>::bsearch (const void *key,
+				  int (*cmp) (const void *, const void *))
+{
+  if (m_vec)
+    return m_vec->bsearch (key, cmp);
+  return NULL;
+}
+
+
 /* Find and return the first position in which OBJ could be inserted
    without changing the ordering of this vector.  LESSTHAN is a
    function that returns true if the first argument is strictly less