optimize.c: Include hashtab.h.

	* cp/optimize.c: Include hashtab.h.
	(struct inline_data): Add tree_pruner.
	(expand_call_inline, expand_calls_inline): Use it when calling
	walk_tree.
	(optimize_function): Initialize and free tree_pruner.

	* g++.old-deja/g++.other/perf1.C: New test.

From-SVN: r41525

gcc/cp/ChangeLog

+2001-04-24  Zack Weinberg  <zackw@stanford.edu>
+
+	* cp/optimize.c: Include hashtab.h.
+	(struct inline_data): Add tree_pruner.
+	(expand_call_inline, expand_calls_inline): Use it when calling
+	walk_tree.
+	(optimize_function): Initialize and free tree_pruner.
+
 2001-04-24  Nathan Sidwell <nathan@codesourcery.com>
 
 	Lazy __FUNCTION__ generation.

gcc/cp/optimize.c

@@ -31,6 +31,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #include "varray.h"
 #include "ggc.h"
 #include "params.h"
+#include "hashtab.h"
 
 /* To Do:
 
@@ -80,6 +81,9 @@ typedef struct inline_data
      distinguish between those two situations.  This flag is true nif
      we are cloning, rather than inlining.  */
   bool cloning_p;
+  /* Hash table used to prevent walk_tree from visiting the same node
+     umpteen million times.  */
+  htab_t tree_pruner;
 } inline_data;
 
 /* Prototypes.  */
@@ -706,7 +710,7 @@ expand_call_inline (tp, walk_subtrees, data)
 	  if (i == 2)
 	    ++id->in_target_cleanup_p;
 	  walk_tree (&TREE_OPERAND (*tp, i), expand_call_inline, data,
-		     NULL);
+		     id->tree_pruner);
 	  if (i == 2)
 	    --id->in_target_cleanup_p;
 	}
@@ -889,8 +893,12 @@ expand_calls_inline (tp, id)
      inline_data *id;
 {
   /* Search through *TP, replacing all calls to inline functions by
-     appropriate equivalents.  */
-  walk_tree (tp, expand_call_inline, id, NULL);
+     appropriate equivalents.  Use walk_tree in no-duplicates mode
+     to avoid exponential time complexity.  (We can't just use
+     walk_tree_without_duplicates, because of the special TARGET_EXPR
+     handling in expand_calls.  The hash table is set up in
+     optimize_function.  */
+  walk_tree (tp, expand_call_inline, id, id->tree_pruner);
 }
 
 /* Optimize the body of FN.  */
@@ -949,9 +957,12 @@ optimize_function (fn)
 
       /* Replace all calls to inline functions with the bodies of those
 	 functions.  */
+      id.tree_pruner = htab_create (37, htab_hash_pointer,
+				    htab_eq_pointer, NULL);
       expand_calls_inline (&DECL_SAVED_TREE (fn), &id);
 
       /* Clean up.  */
+      htab_delete (id.tree_pruner);
       VARRAY_FREE (id.fns);
       VARRAY_FREE (id.target_exprs);
       if (DECL_LANG_SPECIFIC (fn))

gcc/testsuite/ChangeLog

+2001-04-24  Zack Weinberg  <zackw@stanford.edu>
+
+	* g++.old-deja/g++.other/perf1.C: New test.
+
 2001-04-24  Nathan Sidwell <nathan@codesourcery.com>
 
 	* gcc.dg/c99-func-2.c: Remove xfail.

gcc/testsuite/g++.old-deja/g++.other/perf1.C

+// Build don't link:
+
+// Test of severe performance regression from 2.95.  This code generates
+// a heavily self-referential tree which caused the inliner to take
+// O(3**N) time to scan it for function calls.
+// Reported by Kelley Cook <kelley.cook@home.com>.  PR c++/1687.
+
+bool in0 ;
+bool in1 ;
+bool in2 ;
+bool in3 ;
+bool in4 ;
+bool in5 ;
+bool in6 ;
+bool in7 ;
+bool in8 ;
+bool in9 ;
+bool in10;
+bool in11;
+bool in12;
+bool in13;
+bool in14;
+bool in15;
+bool in16;
+bool in17;
+bool in18;
+bool in19;
+bool in20;
+bool in21;
+bool in22;
+bool in23;
+bool in24;
+bool in25;
+bool in26;
+bool in27;
+bool in28;
+bool in29;
+bool in30;
+bool in31;
+unsigned long output;
+
+void mux(void)
+{
+  output =
+      (in0   ?  0x00000001 : 0) |
+      (in1   ?  0x00000002 : 0) |
+      (in2   ?  0x00000004 : 0) |
+      (in3   ?  0x00000008 : 0) |
+      (in4   ?  0x00000010 : 0) |
+      (in5   ?  0x00000020 : 0) |
+      (in6   ?  0x00000040 : 0) |
+      (in7   ?  0x00000080 : 0) |
+      (in8   ?  0x00000100 : 0) |
+      (in9   ?  0x00000200 : 0) |
+      (in10  ?  0x00000400 : 0) |
+      (in11  ?  0x00000800 : 0) |
+      (in12  ?  0x00001000 : 0) |
+      (in13  ?  0x00002000 : 0) |
+      (in14  ?  0x00004000 : 0) |
+      (in15  ?  0x00008000 : 0) |
+      (in16  ?  0x00010000 : 0) |
+      (in17  ?  0x00020000 : 0) |
+      (in18  ?  0x00040000 : 0) |
+      (in19  ?  0x00080000 : 0) |
+      (in20  ?  0x00100000 : 0) |
+      (in21  ?  0x00200000 : 0) |
+      (in22  ?  0x00400000 : 0) |
+      (in23  ?  0x00800000 : 0) |
+      (in24  ?  0x01000000 : 0) |
+      (in25  ?  0x02000000 : 0) |
+      (in26  ?  0x04000000 : 0) |
+      (in27  ?  0x08000000 : 0) |
+      (in28  ?  0x10000000 : 0) |
+      (in29  ?  0x20000000 : 0) |
+      (in30  ?  0x40000000 : 0) |
+      (in31  ?  0x80000000 : 0) ;
+}
+