-/* Return a tree for the sum or difference (RESULTCODE says which)
- of pointer PTROP and integer INTOP. */
-
-static tree
-pointer_int_sum (resultcode, ptrop, intop)
- enum tree_code resultcode;
- tree ptrop, intop;
-{
- tree size_exp;
-
- tree result;
- tree folded;
-
- /* The result is a pointer of the same type that is being added. */
-
- tree result_type = TREE_TYPE (ptrop);
-
- if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
- {
- if (pedantic || warn_pointer_arith)
- pedwarn ("pointer of type `void *' used in arithmetic");
- size_exp = integer_one_node;
- }
- else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
- {
- if (pedantic || warn_pointer_arith)
- pedwarn ("pointer to a function used in arithmetic");
- size_exp = integer_one_node;
- }
- else
- size_exp = c_size_in_bytes (TREE_TYPE (result_type));
-
- /* If what we are about to multiply by the size of the elements
- contains a constant term, apply distributive law
- and multiply that constant term separately.
- This helps produce common subexpressions. */
-
- if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
- && ! TREE_CONSTANT (intop)
- && TREE_CONSTANT (TREE_OPERAND (intop, 1))
- && TREE_CONSTANT (size_exp)
- /* If the constant comes from pointer subtraction,
- skip this optimization--it would cause an error. */
- && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
- /* If the constant is unsigned, and smaller than the pointer size,
- then we must skip this optimization. This is because it could cause
- an overflow error if the constant is negative but INTOP is not. */
- && (! TREE_UNSIGNED (TREE_TYPE (intop))
- || (TYPE_PRECISION (TREE_TYPE (intop))
- == TYPE_PRECISION (TREE_TYPE (ptrop)))))
- {
- enum tree_code subcode = resultcode;
- tree int_type = TREE_TYPE (intop);
- if (TREE_CODE (intop) == MINUS_EXPR)
- subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
- /* Convert both subexpression types to the type of intop,
- because weird cases involving pointer arithmetic
- can result in a sum or difference with different type args. */
- ptrop = build_binary_op (subcode, ptrop,
- convert (int_type, TREE_OPERAND (intop, 1)), 1);
- intop = convert (int_type, TREE_OPERAND (intop, 0));
- }
-
- /* Convert the integer argument to a type the same size as sizetype
- so the multiply won't overflow spuriously. */
-
- if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
- || TREE_UNSIGNED (TREE_TYPE (intop)) != TREE_UNSIGNED (sizetype))
- intop = convert (type_for_size (TYPE_PRECISION (sizetype),
- TREE_UNSIGNED (sizetype)), intop);
-
- /* Replace the integer argument with a suitable product by the object size.
- Do this multiplication as signed, then convert to the appropriate
- pointer type (actually unsigned integral). */
-
- intop = convert (result_type,
- build_binary_op (MULT_EXPR, intop,
- convert (TREE_TYPE (intop), size_exp), 1));
-
- /* Create the sum or difference. */
-
- result = build (resultcode, result_type, ptrop, intop);
-
- folded = fold (result);
- if (folded == result)
- TREE_CONSTANT (folded) = TREE_CONSTANT (ptrop) & TREE_CONSTANT (intop);
- return folded;
-}
-