2011-03-24 Richard Guenther <rguenther@suse.de>

	PR tree-optimization/46562
	* tree.c (build_invariant_address): New function.
	* tree.h (build_invariant_address): Declare.
	* tree-dfa.c (get_addr_base_and_unit_offset): Wrap around
	a renamed function moved ...
	* tree-flow-inline.h (get_addr_base_and_unit_offset_1): ... here.
	Take valueization callback parameter.
	* tree-flow.h (gimple_fold_stmt_to_constant): Declare.
	* gimple-fold.h: New file.
	* tree-ssa-ccp.c (ccp_fold): Use gimple_fold_stmt_to_constant_1.
	(ccp_fold, fold_const_aggregate_ref,
	fold_ctor_reference, fold_nonarray_ctor_reference,
	fold_array_ctor_reference, fold_string_cst_ctor_reference,
	get_base_constructor): Move ...
	* gimple-fold.c: ... here.
	(gimple_fold_stmt_to_constant_1): New function
	split out from ccp_fold.  Take a valueization callback parameter.
	Valueize all operands.
	(gimple_fold_stmt_to_constant): New wrapper function.
	(fold_const_aggregate_ref_1): New function split out from
	fold_const_aggregate_ref.  Take a valueization callback parameter.
	(fold_const_aggregate_ref): Wrap fold_const_aggregate_ref_1.
	* tree-ssa-sccvn.c (simplify_binary_expression): Simplify
	invariant POINTER_PLUS_EXPRs to invariant form.
	(vn_valueize): New function.
	(try_to_simplify): Simplify by using gimple_fold_stmt_to_constant.
	* tree-vrp.c (vrp_valueize): New function.
	(vrp_visit_assignment_or_call): Use gimple_fold_stmt_to_constant
	to fold statements to constants.
	* tree-ssa-pre.c (eliminate): Properly guard propagation of
	function declarations.
	* Makefile.in (tree-ssa-sccvn.o, tree-vrp.o, gimple-fold.o,
	tree-ssa-ccp.o): Add gimple-fold.h dependencies.

	* c-c++-common/pr46562-2.c: New testcase.
	* c-c++-common/pr46562.c: Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@171386 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 135 insertions, 0 deletions

diff --git a/gcc/tree-flow-inline.h b/gcc/tree-flow-inline.h
index 86566101e39..dcbe355e926 100644
--- a/gcc/tree-flow-inline.h
+++ b/gcc/tree-flow-inline.h
@@ -1227,4 +1227,139 @@ make_ssa_name (tree var, gimple stmt)
   return make_ssa_name_fn (cfun, var, stmt);
 }
 
+/* Returns the base object and a constant BITS_PER_UNIT offset in *POFFSET that
+   denotes the starting address of the memory access EXP.
+   Returns NULL_TREE if the offset is not constant or any component
+   is not BITS_PER_UNIT-aligned.
+   VALUEIZE if non-NULL is used to valueize SSA names.  It should return
+   its argument or a constant if the argument is known to be constant.  */
+
+static inline tree
+get_addr_base_and_unit_offset_1 (tree exp, HOST_WIDE_INT *poffset,
+				 tree (*valueize) (tree))
+{
+  HOST_WIDE_INT byte_offset = 0;
+
+  /* Compute cumulative byte-offset for nested component-refs and array-refs,
+     and find the ultimate containing object.  */
+  while (1)
+    {
+      switch (TREE_CODE (exp))
+	{
+	case BIT_FIELD_REF:
+	  return NULL_TREE;
+
+	case COMPONENT_REF:
+	  {
+	    tree field = TREE_OPERAND (exp, 1);
+	    tree this_offset = component_ref_field_offset (exp);
+	    HOST_WIDE_INT hthis_offset;
+
+	    if (!this_offset
+		|| TREE_CODE (this_offset) != INTEGER_CST
+		|| (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
+		    % BITS_PER_UNIT))
+	      return NULL_TREE;
+
+	    hthis_offset = TREE_INT_CST_LOW (this_offset);
+	    hthis_offset += (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
+			     / BITS_PER_UNIT);
+	    byte_offset += hthis_offset;
+	  }
+	  break;
+
+	case ARRAY_REF:
+	case ARRAY_RANGE_REF:
+	  {
+	    tree index = TREE_OPERAND (exp, 1);
+	    tree low_bound, unit_size;
+
+	    if (valueize
+		&& TREE_CODE (index) == SSA_NAME)
+	      index = (*valueize) (index);
+
+	    /* If the resulting bit-offset is constant, track it.  */
+	    if (TREE_CODE (index) == INTEGER_CST
+		&& (low_bound = array_ref_low_bound (exp),
+		    TREE_CODE (low_bound) == INTEGER_CST)
+		&& (unit_size = array_ref_element_size (exp),
+		    TREE_CODE (unit_size) == INTEGER_CST))
+	      {
+		HOST_WIDE_INT hindex = TREE_INT_CST_LOW (index);
+
+		hindex -= TREE_INT_CST_LOW (low_bound);
+		hindex *= TREE_INT_CST_LOW (unit_size);
+		byte_offset += hindex;
+	      }
+	    else
+	      return NULL_TREE;
+	  }
+	  break;
+
+	case REALPART_EXPR:
+	  break;
+
+	case IMAGPART_EXPR:
+	  byte_offset += TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (exp)));
+	  break;
+
+	case VIEW_CONVERT_EXPR:
+	  break;
+
+	case MEM_REF:
+	  {
+	    tree base = TREE_OPERAND (exp, 0);
+	    if (valueize
+		&& TREE_CODE (base) == SSA_NAME)
+	      base = (*valueize) (base);
+
+	    /* Hand back the decl for MEM[&decl, off].  */
+	    if (TREE_CODE (base) == ADDR_EXPR)
+	      {
+		if (!integer_zerop (TREE_OPERAND (exp, 1)))
+		  {
+		    double_int off = mem_ref_offset (exp);
+		    gcc_assert (off.high == -1 || off.high == 0);
+		    byte_offset += double_int_to_shwi (off);
+		  }
+		exp = TREE_OPERAND (base, 0);
+	      }
+	    goto done;
+	  }
+
+	case TARGET_MEM_REF:
+	  {
+	    tree base = TREE_OPERAND (exp, 0);
+	    if (valueize
+		&& TREE_CODE (base) == SSA_NAME)
+	      base = (*valueize) (base);
+
+	    /* Hand back the decl for MEM[&decl, off].  */
+	    if (TREE_CODE (base) == ADDR_EXPR)
+	      {
+		if (TMR_INDEX (exp) || TMR_INDEX2 (exp))
+		  return NULL_TREE;
+		if (!integer_zerop (TMR_OFFSET (exp)))
+		  {
+		    double_int off = mem_ref_offset (exp);
+		    gcc_assert (off.high == -1 || off.high == 0);
+		    byte_offset += double_int_to_shwi (off);
+		  }
+		exp = TREE_OPERAND (base, 0);
+	      }
+	    goto done;
+	  }
+
+	default:
+	  goto done;
+	}
+
+      exp = TREE_OPERAND (exp, 0);
+    }
+done:
+
+  *poffset = byte_offset;
+  return exp;
+}
+
 #endif /* _TREE_FLOW_INLINE_H  */