re PR middle-end/28755 (duplicate members of arrays)

	PR middle-end/28755
	* expr.c (expand_constructor): New function.
	(expand_expr_real_1) <case CONSTRUCTOR>: Call it.
	(expand_expr_real_1) <case ARRAY_REF>: Call it if VALUE is
	CONSTRUCTOR.

	* gcc.dg/pr28755.c: New test.

From-SVN: r128685

1 files changed, 103 insertions, 69 deletions

diff --git a/gcc/expr.c b/gcc/expr.c
index 9302810..c7b29b5 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -6887,6 +6887,89 @@ expand_expr_addr_expr (tree exp, rtx target, enum machine_mode tmode,
   return result;
 }
 
+/* Generate code for computing CONSTRUCTOR EXP.
+   An rtx for the computed value is returned.  If AVOID_TEMP_MEM
+   is TRUE, instead of creating a temporary variable in memory
+   NULL is returned and the caller needs to handle it differently.  */
+
+static rtx
+expand_constructor (tree exp, rtx target, enum expand_modifier modifier,
+		    bool avoid_temp_mem)
+{
+  tree type = TREE_TYPE (exp);
+  enum machine_mode mode = TYPE_MODE (type);
+
+  /* Try to avoid creating a temporary at all.  This is possible
+     if all of the initializer is zero.
+     FIXME: try to handle all [0..255] initializers we can handle
+     with memset.  */
+  if (TREE_STATIC (exp)
+      && !TREE_ADDRESSABLE (exp)
+      && target != 0 && mode == BLKmode
+      && all_zeros_p (exp))
+    {
+      clear_storage (target, expr_size (exp), BLOCK_OP_NORMAL);
+      return target;
+    }
+
+  /* All elts simple constants => refer to a constant in memory.  But
+     if this is a non-BLKmode mode, let it store a field at a time
+     since that should make a CONST_INT or CONST_DOUBLE when we
+     fold.  Likewise, if we have a target we can use, it is best to
+     store directly into the target unless the type is large enough
+     that memcpy will be used.  If we are making an initializer and
+     all operands are constant, put it in memory as well.
+
+     FIXME: Avoid trying to fill vector constructors piece-meal.
+     Output them with output_constant_def below unless we're sure
+     they're zeros.  This should go away when vector initializers
+     are treated like VECTOR_CST instead of arrays.  */
+  if ((TREE_STATIC (exp)
+       && ((mode == BLKmode
+	    && ! (target != 0 && safe_from_p (target, exp, 1)))
+		  || TREE_ADDRESSABLE (exp)
+		  || (host_integerp (TYPE_SIZE_UNIT (type), 1)
+		      && (! MOVE_BY_PIECES_P
+				     (tree_low_cst (TYPE_SIZE_UNIT (type), 1),
+				      TYPE_ALIGN (type)))
+		      && ! mostly_zeros_p (exp))))
+      || ((modifier == EXPAND_INITIALIZER || modifier == EXPAND_CONST_ADDRESS)
+	  && TREE_CONSTANT (exp)))
+    {
+      rtx constructor;
+
+      if (avoid_temp_mem)
+	return NULL_RTX;
+
+      constructor = expand_expr_constant (exp, 1, modifier);
+
+      if (modifier != EXPAND_CONST_ADDRESS
+	  && modifier != EXPAND_INITIALIZER
+	  && modifier != EXPAND_SUM)
+	constructor = validize_mem (constructor);
+
+      return constructor;
+    }
+
+  /* Handle calls that pass values in multiple non-contiguous
+     locations.  The Irix 6 ABI has examples of this.  */
+  if (target == 0 || ! safe_from_p (target, exp, 1)
+      || GET_CODE (target) == PARALLEL || modifier == EXPAND_STACK_PARM)
+    {
+      if (avoid_temp_mem)
+	return NULL_RTX;
+
+      target
+	= assign_temp (build_qualified_type (type, (TYPE_QUALS (type)
+						    | (TREE_READONLY (exp)
+						       * TYPE_QUAL_CONST))),
+		       0, TREE_ADDRESSABLE (exp), 1);
+    }
+
+  store_constructor (exp, target, 0, int_expr_size (exp));
+  return target;
+}
+
 
 /* expand_expr: generate code for computing expression EXP.
    An rtx for the computed value is returned.  The value is never null.
@@ -7379,71 +7462,7 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
 	  return const0_rtx;
 	}
 
-      /* Try to avoid creating a temporary at all.  This is possible
-	 if all of the initializer is zero.
-	 FIXME: try to handle all [0..255] initializers we can handle
-	 with memset.  */
-      else if (TREE_STATIC (exp)
-	       && !TREE_ADDRESSABLE (exp)
-	       && target != 0 && mode == BLKmode
-	       && all_zeros_p (exp))
-	{
-	  clear_storage (target, expr_size (exp), BLOCK_OP_NORMAL);
-	  return target;
-	}
-
-      /* All elts simple constants => refer to a constant in memory.  But
-	 if this is a non-BLKmode mode, let it store a field at a time
-	 since that should make a CONST_INT or CONST_DOUBLE when we
-	 fold.  Likewise, if we have a target we can use, it is best to
-	 store directly into the target unless the type is large enough
-	 that memcpy will be used.  If we are making an initializer and
-	 all operands are constant, put it in memory as well.
-
-	FIXME: Avoid trying to fill vector constructors piece-meal.
-	Output them with output_constant_def below unless we're sure
-	they're zeros.  This should go away when vector initializers
-	are treated like VECTOR_CST instead of arrays.
-      */
-      else if ((TREE_STATIC (exp)
-		&& ((mode == BLKmode
-		     && ! (target != 0 && safe_from_p (target, exp, 1)))
-		    || TREE_ADDRESSABLE (exp)
-		    || (host_integerp (TYPE_SIZE_UNIT (type), 1)
-			&& (! MOVE_BY_PIECES_P
-			    (tree_low_cst (TYPE_SIZE_UNIT (type), 1),
-			     TYPE_ALIGN (type)))
-			&& ! mostly_zeros_p (exp))))
-	       || ((modifier == EXPAND_INITIALIZER
-		    || modifier == EXPAND_CONST_ADDRESS)
-		   && TREE_CONSTANT (exp)))
-	{
-	  rtx constructor = expand_expr_constant (exp, 1, modifier);
-
-	  if (modifier != EXPAND_CONST_ADDRESS
-	      && modifier != EXPAND_INITIALIZER
-	      && modifier != EXPAND_SUM)
-	    constructor = validize_mem (constructor);
-
-	  return constructor;
-	}
-      else
-	{
-	  /* Handle calls that pass values in multiple non-contiguous
-	     locations.  The Irix 6 ABI has examples of this.  */
-	  if (target == 0 || ! safe_from_p (target, exp, 1)
-	      || GET_CODE (target) == PARALLEL
-	      || modifier == EXPAND_STACK_PARM)
-	    target
-	      = assign_temp (build_qualified_type (type,
-						   (TYPE_QUALS (type)
-						    | (TREE_READONLY (exp)
-						       * TYPE_QUAL_CONST))),
-			     0, TREE_ADDRESSABLE (exp), 1);
-
-	  store_constructor (exp, target, 0, int_expr_size (exp));
-	  return target;
-	}
+      return expand_constructor (exp, target, modifier, false);
 
     case MISALIGNED_INDIRECT_REF:
     case ALIGN_INDIRECT_REF:
@@ -7585,10 +7604,25 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
 					      field, value)
 		      if (tree_int_cst_equal (field, index))
 			{
-			  if (!TREE_SIDE_EFFECTS (value))
-			    return expand_expr (fold (value), target, tmode,
-						modifier);
-			  break;
+			  if (TREE_SIDE_EFFECTS (value))
+			    break;
+
+			  if (TREE_CODE (value) == CONSTRUCTOR)
+			    {
+			      /* If VALUE is a CONSTRUCTOR, this
+				 optimization is only useful if
+				 this doesn't store the CONSTRUCTOR
+				 into memory.  If it does, it is more
+				 efficient to just load the data from
+				 the array directly.  */
+			      rtx ret = expand_constructor (value, target,
+							    modifier, true);
+			      if (ret == NULL_RTX)
+				break;
+			    }
+
+			  return expand_expr (fold (value), target, tmode,
+					      modifier);
 			}
 		  }
 		else if(TREE_CODE (init) == STRING_CST)