[PATCH] Fix PR54825

[Richard Guenther]

This fixes PR54825, properly FRE/PRE vector BIT_FIELD_REFs.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2012-10-08  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/54825
	* tree-ssa-sccvn.c (vn_nary_length_from_stmt): Handle BIT_FIELD_REF.
	(init_vn_nary_op_from_stmt): Likewise.
	* tree-ssa-pre.c (compute_avail): Use vn_nary_op_lookup_stmt.
	* tree-ssa-sccvn.h (sizeof_vn_nary_op): Avoid overflow.

Index: gcc/tree-ssa-sccvn.c
===================================================================
*** gcc/tree-ssa-sccvn.c	(revision 192120)
--- gcc/tree-ssa-sccvn.c	(working copy)
*************** vn_nary_length_from_stmt (gimple stmt)
*** 2194,2199 ****
--- 2194,2202 ----
      case VIEW_CONVERT_EXPR:
        return 1;
  
+     case BIT_FIELD_REF:
+       return 3;
+ 
      case CONSTRUCTOR:
        return CONSTRUCTOR_NELTS (gimple_assign_rhs1 (stmt));
  
*************** init_vn_nary_op_from_stmt (vn_nary_op_t
*** 2220,2225 ****
--- 2223,2235 ----
        vno->op[0] = TREE_OPERAND (gimple_assign_rhs1 (stmt), 0);
        break;
  
+     case BIT_FIELD_REF:
+       vno->length = 3;
+       vno->op[0] = TREE_OPERAND (gimple_assign_rhs1 (stmt), 0);
+       vno->op[1] = TREE_OPERAND (gimple_assign_rhs1 (stmt), 1);
+       vno->op[2] = TREE_OPERAND (gimple_assign_rhs1 (stmt), 2);
+       break;
+ 
      case CONSTRUCTOR:
        vno->length = CONSTRUCTOR_NELTS (gimple_assign_rhs1 (stmt));
        for (i = 0; i < vno->length; ++i)
*************** init_vn_nary_op_from_stmt (vn_nary_op_t
*** 2227,2232 ****
--- 2237,2243 ----
        break;
  
      default:
+       gcc_checking_assert (!gimple_assign_single_p (stmt));
        vno->length = gimple_num_ops (stmt) - 1;
        for (i = 0; i < vno->length; ++i)
  	vno->op[i] = gimple_op (stmt, i + 1);
Index: gcc/tree-ssa-pre.c
===================================================================
*** gcc/tree-ssa-pre.c	(revision 192120)
--- gcc/tree-ssa-pre.c	(working copy)
*************** compute_avail (void)
*** 3850,3860 ****
  			  || code == VEC_COND_EXPR)
  			continue;
  
! 		      vn_nary_op_lookup_pieces (gimple_num_ops (stmt) - 1,
! 						code,
! 						gimple_expr_type (stmt),
! 						gimple_assign_rhs1_ptr (stmt),
! 						&nary);
  		      if (!nary)
  			continue;
  
--- 3850,3856 ----
  			  || code == VEC_COND_EXPR)
  			continue;
  
! 		      vn_nary_op_lookup_stmt (stmt, &nary);
  		      if (!nary)
  			continue;
  
Index: gcc/tree-ssa-sccvn.h
===================================================================
*** gcc/tree-ssa-sccvn.h	(revision 192120)
--- gcc/tree-ssa-sccvn.h	(working copy)
*************** typedef const struct vn_nary_op_s *const
*** 51,57 ****
  static inline size_t
  sizeof_vn_nary_op (unsigned int length)
  {
!   return sizeof (struct vn_nary_op_s) + sizeof (tree) * (length - 1);
  }
  
  /* Phi nodes in the hashtable consist of their non-VN_TOP phi
--- 51,57 ----
  static inline size_t
  sizeof_vn_nary_op (unsigned int length)
  {
!   return sizeof (struct vn_nary_op_s) + sizeof (tree) * length - sizeof (tree);
  }
  
  /* Phi nodes in the hashtable consist of their non-VN_TOP phi