re PR target/35659 (Miscompiled code with -O2 (but not with -O2 -funroll-loops) on ia64)

2009-02-06  Paolo Bonzini  <bonzini@gnu.org>

	PR tree-optimization/35659
	* tree-ssa-sccvn.c (vn_constant_eq, vn_reference_eq, vn_nary_op_eq
	vn_phi_eq): Shortcut if hashcode does not match.
	(vn_reference_op_compute_hash): Do not call iterative_hash_expr for
	NULL operands.
	* tree-ssa-pre.c (pre_expr_hash): Look at hashcode if available,
	and avoid iterative_hash_expr.
	(FOR_EACH_VALUE_ID_IN_SET): New.
	(value_id_compare): Remove.
	(sorted_array_from_bitmap_set): Use FOR_EACH_VALUE_ID_IN_SET to
	sort expressions by value id.

From-SVN: r143980

gcc/ChangeLog

@@ -1,3 +1,17 @@
+2009-02-06  Paolo Bonzini  <bonzini@gnu.org>
+
+	PR tree-optimization/35659
+	* tree-ssa-sccvn.c (vn_constant_eq, vn_reference_eq, vn_nary_op_eq
+	vn_phi_eq): Shortcut if hashcode does not match.
+	(vn_reference_op_compute_hash): Do not call iterative_hash_expr for
+	NULL operands.
+	* tree-ssa-pre.c (pre_expr_hash): Look at hashcode if available,
+	and avoid iterative_hash_expr.
+	(FOR_EACH_VALUE_ID_IN_SET): New.
+	(value_id_compare): Remove.
+	(sorted_array_from_bitmap_set): Use FOR_EACH_VALUE_ID_IN_SET to
+	sort expressions by value id.
+
 2009-02-05  Kaz Kojima  <kkojima@gcc.gnu.org>
 
 	PR target/38991

gcc/tree-ssa-pre.c

@@ -216,11 +216,11 @@ pre_expr_hash (const void *p1)
     case CONSTANT:
       return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e));
     case NAME:
-      return iterative_hash_expr (PRE_EXPR_NAME (e), 0);
+      return iterative_hash_hashval_t (SSA_NAME_VERSION (PRE_EXPR_NAME (e)), 0);
     case NARY:
-      return vn_nary_op_compute_hash (PRE_EXPR_NARY (e));
+      return PRE_EXPR_NARY (e)->hashcode;
     case REFERENCE:
-      return vn_reference_compute_hash (PRE_EXPR_REFERENCE (e));
+      return PRE_EXPR_REFERENCE (e)->hashcode;
     default:
       abort ();
     }
@@ -337,6 +337,9 @@ typedef struct bitmap_set
 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi)		\
   EXECUTE_IF_SET_IN_BITMAP((set)->expressions, 0, (id), (bi))
 
+#define FOR_EACH_VALUE_ID_IN_SET(set, id, bi)		\
+  EXECUTE_IF_SET_IN_BITMAP((set)->values, 0, (id), (bi))
+
 /* Mapping from value id to expressions with that value_id.  */
 DEF_VEC_P (bitmap_set_t);
 DEF_VEC_ALLOC_P (bitmap_set_t, heap);
@@ -672,33 +675,34 @@ bitmap_set_free (bitmap_set_t set)
 }
 
 
-/* A comparison function for use in qsort to top sort a bitmap set.  Simply
-   subtracts value ids, since they are created with leaves before
-   their parent users (IE topological order).  */
-
-static int
-value_id_compare (const void *pa, const void *pb)
-{
-  const unsigned int vha = get_expr_value_id (*((const pre_expr *)pa));
-  const unsigned int vhb = get_expr_value_id (*((const pre_expr *)pb));
-
-  return vha - vhb;
-}
-
 /* Generate an topological-ordered array of bitmap set SET.  */
 
 static VEC(pre_expr, heap) *
 sorted_array_from_bitmap_set (bitmap_set_t set)
 {
-  unsigned int i;
-  bitmap_iterator bi;
+  unsigned int i, j;
+  bitmap_iterator bi, bj;
   VEC(pre_expr, heap) *result = NULL;
 
-  FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
-    VEC_safe_push (pre_expr, heap, result, expression_for_id (i));
+  FOR_EACH_VALUE_ID_IN_SET (set, i, bi)
+    {
+      /* The number of expressions having a given value is usually
+	 relatively small.  Thus, rather than making a vector of all
+	 the expressions and sorting it by value-id, we walk the values
+	 and check in the reverse mapping that tells us what expressions
+	 have a given value, to filter those in our set.  As a result,
+	 the expressions are inserted in value-id order, which means
+	 topological order.
 
-  qsort (VEC_address (pre_expr, result), VEC_length (pre_expr, result),
-	 sizeof (pre_expr), value_id_compare);
+	 If this is somehow a significant lose for some cases, we can
+	 choose which set to walk based on the set size.  */
+      bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, i);
+      FOR_EACH_EXPR_ID_IN_SET (exprset, j, bj)
+	{
+	  if (bitmap_bit_p (set->expressions, j))
+	    VEC_safe_push (pre_expr, heap, result, expression_for_id (j));
+        }
+    }
 
   return result;
 }

gcc/tree-ssa-sccvn.c

@@ -316,6 +316,9 @@ vn_constant_eq (const void *p1, const void *p2)
   const struct vn_constant_s *vc1 = (const struct vn_constant_s *) p1;
   const struct vn_constant_s *vc2 = (const struct vn_constant_s *) p2;
 
+  if (vc1->hashcode != vc2->hashcode)
+    return false;
+
   return vn_constant_eq_with_type (vc1->constant, vc2->constant);
 }
 
@@ -386,6 +389,7 @@ vn_reference_op_eq (const void *p1, const void *p2)
 {
   const_vn_reference_op_t const vro1 = (const_vn_reference_op_t) p1;
   const_vn_reference_op_t const vro2 = (const_vn_reference_op_t) p2;
+
   return vro1->opcode == vro2->opcode
     && types_compatible_p (vro1->type, vro2->type)
     && expressions_equal_p (vro1->op0, vro2->op0)
@@ -398,9 +402,14 @@ vn_reference_op_eq (const void *p1, const void *p2)
 static hashval_t
 vn_reference_op_compute_hash (const vn_reference_op_t vro1)
 {
-  return iterative_hash_expr (vro1->op0, vro1->opcode)
-    + iterative_hash_expr (vro1->op1, vro1->opcode)
-    + iterative_hash_expr (vro1->op2, vro1->opcode);
+  hashval_t result = 0;
+  if (vro1->op0)
+    result += iterative_hash_expr (vro1->op0, vro1->opcode);
+  if (vro1->op1)
+    result += iterative_hash_expr (vro1->op1, vro1->opcode);
+  if (vro1->op2)
+    result += iterative_hash_expr (vro1->op2, vro1->opcode);
+  return result;
 }
 
 /* Return the hashcode for a given reference operation P1.  */
@@ -442,6 +451,8 @@ vn_reference_eq (const void *p1, const void *p2)
 
   const_vn_reference_t const vr1 = (const_vn_reference_t) p1;
   const_vn_reference_t const vr2 = (const_vn_reference_t) p2;
+  if (vr1->hashcode != vr2->hashcode)
+    return false;
 
   if (vr1->vuses == vr2->vuses
       && vr1->operands == vr2->operands)
@@ -1183,6 +1194,9 @@ vn_nary_op_eq (const void *p1, const void *p2)
   const_vn_nary_op_t const vno2 = (const_vn_nary_op_t) p2;
   unsigned i;
 
+  if (vno1->hashcode != vno2->hashcode)
+    return false;
+
   if (vno1->opcode != vno2->opcode
       || !types_compatible_p (vno1->type, vno2->type))
     return false;
@@ -1449,6 +1463,9 @@ vn_phi_eq (const void *p1, const void *p2)
   const_vn_phi_t const vp1 = (const_vn_phi_t) p1;
   const_vn_phi_t const vp2 = (const_vn_phi_t) p2;
 
+  if (vp1->hashcode != vp2->hashcode)
+    return false;
+
   if (vp1->block == vp2->block)
     {
       int i;