re PR tree-optimization/34683 (SSA rewriting in the loop unroller causes quadratic behavior)

2008-01-07  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/34683
	* tree-ssa-sccvn.c (vuses_to_vec): Pre-allocate the vector of
	VOPs of the needed size to save memory.  Use VEC_quick_push
	to save compile-time.
	(vdefs_to_vec): Likewise.

From-SVN: r131375

gcc/ChangeLog

+2008-01-07  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/34683
+	* tree-ssa-sccvn.c (vuses_to_vec): Pre-allocate the vector of
+	VOPs of the needed size to save memory.  Use VEC_quick_push
+	to save compile-time.
+	(vdefs_to_vec): Likewise.
+
 2008-01-07  Sa Liu  <saliu@de.ibm.com>
+
 	* config/spu/spu.md (divdf3): Genetate inline code for double division. 
 	The implementation doesn't handle INF or NAN, therefore it only applies 
 	when -ffinite-math-only is given.

gcc/tree-ssa-sccvn.c

@@ -389,8 +389,10 @@ vuses_to_vec (tree stmt, VEC (tree, gc) **result)
   if (!stmt)
     return;
 
+  *result = VEC_alloc (tree, gc, num_ssa_operands (stmt, SSA_OP_VIRTUAL_USES));
+
   FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, iter, SSA_OP_VIRTUAL_USES)
-    VEC_safe_push (tree, gc, *result, vuse);
+    VEC_quick_push (tree, *result, vuse);
 
   if (VEC_length (tree, *result) > 1)
     sort_vuses (*result);
@@ -421,8 +423,10 @@ vdefs_to_vec (tree stmt, VEC (tree, gc) **result)
   if (!stmt)
     return;
 
+  *result = VEC_alloc (tree, gc, num_ssa_operands (stmt, SSA_OP_VIRTUAL_DEFS));
+
   FOR_EACH_SSA_TREE_OPERAND (vdef, stmt, iter, SSA_OP_VIRTUAL_DEFS)
-    VEC_safe_push (tree, gc, *result, vdef);
+    VEC_quick_push (tree, *result, vdef);
 
   if (VEC_length (tree, *result) > 1)
     sort_vuses (*result);