static tree fold_negate_const (tree, tree);
static tree fold_not_const (tree, tree);
static tree fold_relational_const (enum tree_code, tree, tree, tree);
-static tree fold_relational_hi_lo (enum tree_code *, const tree,
- tree *, tree *);
static bool tree_expr_nonzero_p (tree);
/* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
}
/* Comparisons with the highest or lowest possible integer of
- the specified size will have known values.
-
- This is quite similar to fold_relational_hi_lo, however,
- attempts to share the code have been nothing but trouble. */
+ the specified size will have known values. */
{
int width = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (arg1)));
return false;
}
-/* See if we are applying CODE, a relational to the highest or lowest
- possible integer of TYPE. If so, then the result is a compile
- time constant. */
-
-static tree
-fold_relational_hi_lo (enum tree_code *code_p, const tree type, tree *op0_p,
- tree *op1_p)
-{
- tree op0 = *op0_p;
- tree op1 = *op1_p;
- enum tree_code code = *code_p;
- int width = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (op1)));
-
- if (TREE_CODE (op1) == INTEGER_CST
- && ! TREE_CONSTANT_OVERFLOW (op1)
- && width <= HOST_BITS_PER_WIDE_INT
- && (INTEGRAL_TYPE_P (TREE_TYPE (op1))
- || POINTER_TYPE_P (TREE_TYPE (op1))))
- {
- unsigned HOST_WIDE_INT signed_max;
- unsigned HOST_WIDE_INT max, min;
-
- signed_max = ((unsigned HOST_WIDE_INT) 1 << (width - 1)) - 1;
-
- if (TYPE_UNSIGNED (TREE_TYPE (op1)))
- {
- max = ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1;
- min = 0;
- }
- else
- {
- max = signed_max;
- min = ((unsigned HOST_WIDE_INT) -1 << (width - 1));
- }
-
- if (TREE_INT_CST_HIGH (op1) == 0
- && TREE_INT_CST_LOW (op1) == max)
- switch (code)
- {
- case GT_EXPR:
- return omit_one_operand (type, integer_zero_node, op0);
-
- case GE_EXPR:
- *code_p = EQ_EXPR;
- break;
- case LE_EXPR:
- return omit_one_operand (type, integer_one_node, op0);
-
- case LT_EXPR:
- *code_p = NE_EXPR;
- break;
-
- /* The GE_EXPR and LT_EXPR cases above are not normally
- reached because of previous transformations. */
-
- default:
- break;
- }
- else if (TREE_INT_CST_HIGH (op1) == 0
- && TREE_INT_CST_LOW (op1) == max - 1)
- switch (code)
- {
- case GT_EXPR:
- *code_p = EQ_EXPR;
- *op1_p = const_binop (PLUS_EXPR, op1, integer_one_node, 0);
- break;
- case LE_EXPR:
- *code_p = NE_EXPR;
- *op1_p = const_binop (PLUS_EXPR, op1, integer_one_node, 0);
- break;
- default:
- break;
- }
- else if (TREE_INT_CST_HIGH (op1) == (min ? -1 : 0)
- && TREE_INT_CST_LOW (op1) == min)
- switch (code)
- {
- case LT_EXPR:
- return omit_one_operand (type, integer_zero_node, op0);
-
- case LE_EXPR:
- *code_p = EQ_EXPR;
- break;
-
- case GE_EXPR:
- return omit_one_operand (type, integer_one_node, op0);
-
- case GT_EXPR:
- *code_p = NE_EXPR;
- break;
-
- default:
- break;
- }
- else if (TREE_INT_CST_HIGH (op1) == (min ? -1 : 0)
- && TREE_INT_CST_LOW (op1) == min + 1)
- switch (code)
- {
- case GE_EXPR:
- *code_p = NE_EXPR;
- *op1_p = const_binop (MINUS_EXPR, op1, integer_one_node, 0);
- break;
- case LT_EXPR:
- *code_p = EQ_EXPR;
- *op1_p = const_binop (MINUS_EXPR, op1, integer_one_node, 0);
- break;
- default:
- break;
- }
-
- else if (TREE_INT_CST_HIGH (op1) == 0
- && TREE_INT_CST_LOW (op1) == signed_max
- && TYPE_UNSIGNED (TREE_TYPE (op1))
- /* signed_type does not work on pointer types. */
- && INTEGRAL_TYPE_P (TREE_TYPE (op1)))
- {
- /* The following case also applies to X < signed_max+1
- and X >= signed_max+1 because previous transformations. */
- if (code == LE_EXPR || code == GT_EXPR)
- {
- tree st0, st1, exp, retval;
- st0 = lang_hooks.types.signed_type (TREE_TYPE (op0));
- st1 = lang_hooks.types.signed_type (TREE_TYPE (op1));
-
- exp = build2 (code == LE_EXPR ? GE_EXPR: LT_EXPR,
- type,
- fold_convert (st0, op0),
- fold_convert (st1, integer_zero_node));
-
- retval = fold_binary_to_constant (TREE_CODE (exp),
- TREE_TYPE (exp),
- TREE_OPERAND (exp, 0),
- TREE_OPERAND (exp, 1));
-
- /* If we are in gimple form, then returning EXP would create
- non-gimple expressions. Clearing it is safe and insures
- we do not allow a non-gimple expression to escape. */
- if (in_gimple_form)
- exp = NULL;
-
- return (retval ? retval : exp);
- }
- }
- }
-
- return NULL_TREE;
-}
-
-
/* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
attempt to fold the expression to a constant without modifying TYPE,
OP0 or OP1.
tree
fold_binary_to_constant (enum tree_code code, tree type, tree op0, tree op1)
{
- int wins = 1;
- tree subop0;
- tree subop1;
- tree tem;
-
- /* If this is a commutative operation, and ARG0 is a constant, move it
- to ARG1 to reduce the number of tests below. */
- if (commutative_tree_code (code)
- && (TREE_CODE (op0) == INTEGER_CST || TREE_CODE (op0) == REAL_CST))
- {
- tem = op0;
- op0 = op1;
- op1 = tem;
- }
-
- /* If either operand is a complex type, extract its real component. */
- if (TREE_CODE (op0) == COMPLEX_CST)
- subop0 = TREE_REALPART (op0);
- else
- subop0 = op0;
-
- if (TREE_CODE (op1) == COMPLEX_CST)
- subop1 = TREE_REALPART (op1);
- else
- subop1 = op1;
-
- /* Note if either argument is not a real or integer constant.
- With a few exceptions, simplification is limited to cases
- where both arguments are constants. */
- if ((TREE_CODE (subop0) != INTEGER_CST
- && TREE_CODE (subop0) != REAL_CST)
- || (TREE_CODE (subop1) != INTEGER_CST
- && TREE_CODE (subop1) != REAL_CST))
- wins = 0;
-
- switch (code)
- {
- case PLUS_EXPR:
- /* (plus (address) (const_int)) is a constant. */
- if (TREE_CODE (op0) == PLUS_EXPR
- && TREE_CODE (op1) == INTEGER_CST
- && (TREE_CODE (TREE_OPERAND (op0, 0)) == ADDR_EXPR
- || (TREE_CODE (TREE_OPERAND (op0, 0)) == NOP_EXPR
- && (TREE_CODE (TREE_OPERAND (TREE_OPERAND (op0, 0), 0))
- == ADDR_EXPR)))
- && TREE_CODE (TREE_OPERAND (op0, 1)) == INTEGER_CST)
- {
- return build2 (PLUS_EXPR, type, TREE_OPERAND (op0, 0),
- const_binop (PLUS_EXPR, op1,
- TREE_OPERAND (op0, 1), 0));
- }
- case BIT_XOR_EXPR:
-
- binary:
- if (!wins)
- return NULL_TREE;
-
- /* Both arguments are constants. Simplify. */
- tem = const_binop (code, op0, op1, 0);
- if (tem != NULL_TREE)
- {
- /* The return value should always have the same type as
- the original expression. */
- if (TREE_TYPE (tem) != type)
- tem = fold_convert (type, tem);
-
- return tem;
- }
- return NULL_TREE;
-
- case MINUS_EXPR:
- /* Fold &x - &x. This can happen from &x.foo - &x.
- This is unsafe for certain floats even in non-IEEE formats.
- In IEEE, it is unsafe because it does wrong for NaNs.
- Also note that operand_equal_p is always false if an
- operand is volatile. */
- if (! FLOAT_TYPE_P (type) && operand_equal_p (op0, op1, 0))
- return fold_convert (type, integer_zero_node);
-
- goto binary;
-
- case MULT_EXPR:
- case BIT_AND_EXPR:
- /* Special case multiplication or bitwise AND where one argument
- is zero. */
- if (! FLOAT_TYPE_P (type) && integer_zerop (op1))
- return omit_one_operand (type, op1, op0);
- else
- if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (op0)))
- && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (op0)))
- && real_zerop (op1))
- return omit_one_operand (type, op1, op0);
-
- goto binary;
-
- case BIT_IOR_EXPR:
- /* Special case when we know the result will be all ones. */
- if (integer_all_onesp (op1))
- return omit_one_operand (type, op1, op0);
-
- goto binary;
-
- case TRUNC_DIV_EXPR:
- case ROUND_DIV_EXPR:
- case FLOOR_DIV_EXPR:
- case CEIL_DIV_EXPR:
- case EXACT_DIV_EXPR:
- case TRUNC_MOD_EXPR:
- case ROUND_MOD_EXPR:
- case FLOOR_MOD_EXPR:
- case CEIL_MOD_EXPR:
- case RDIV_EXPR:
- /* Division by zero is undefined. */
- if (integer_zerop (op1))
- return NULL_TREE;
-
- if (TREE_CODE (op1) == REAL_CST
- && !MODE_HAS_INFINITIES (TYPE_MODE (TREE_TYPE (op1)))
- && real_zerop (op1))
- return NULL_TREE;
-
- goto binary;
-
- case MIN_EXPR:
- if (INTEGRAL_TYPE_P (type)
- && operand_equal_p (op1, TYPE_MIN_VALUE (type), OEP_ONLY_CONST))
- return omit_one_operand (type, op1, op0);
-
- goto binary;
-
- case MAX_EXPR:
- if (INTEGRAL_TYPE_P (type)
- && TYPE_MAX_VALUE (type)
- && operand_equal_p (op1, TYPE_MAX_VALUE (type), OEP_ONLY_CONST))
- return omit_one_operand (type, op1, op0);
-
- goto binary;
-
- case RSHIFT_EXPR:
- /* Optimize -1 >> x for arithmetic right shifts. */
- if (integer_all_onesp (op0) && ! TYPE_UNSIGNED (type))
- return omit_one_operand (type, op0, op1);
- /* ... fall through ... */
-
- case LSHIFT_EXPR:
- if (integer_zerop (op0))
- return omit_one_operand (type, op0, op1);
-
- /* Since negative shift count is not well-defined, don't
- try to compute it in the compiler. */
- if (TREE_CODE (op1) == INTEGER_CST && tree_int_cst_sgn (op1) < 0)
- return NULL_TREE;
-
- goto binary;
-
- case LROTATE_EXPR:
- case RROTATE_EXPR:
- /* -1 rotated either direction by any amount is still -1. */
- if (integer_all_onesp (op0))
- return omit_one_operand (type, op0, op1);
-
- /* 0 rotated either direction by any amount is still zero. */
- if (integer_zerop (op0))
- return omit_one_operand (type, op0, op1);
-
- goto binary;
-
- case COMPLEX_EXPR:
- if (wins)
- return build_complex (type, op0, op1);
- return NULL_TREE;
-
- case LT_EXPR:
- case LE_EXPR:
- case GT_EXPR:
- case GE_EXPR:
- case EQ_EXPR:
- case NE_EXPR:
- /* If one arg is a real or integer constant, put it last. */
- if ((TREE_CODE (op0) == INTEGER_CST
- && TREE_CODE (op1) != INTEGER_CST)
- || (TREE_CODE (op0) == REAL_CST
- && TREE_CODE (op0) != REAL_CST))
- {
- tree temp;
-
- temp = op0;
- op0 = op1;
- op1 = temp;
- code = swap_tree_comparison (code);
- }
-
- /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0.
- This transformation affects the cases which are handled in later
- optimizations involving comparisons with non-negative constants. */
- if (TREE_CODE (op1) == INTEGER_CST
- && TREE_CODE (op0) != INTEGER_CST
- && tree_int_cst_sgn (op1) > 0)
- {
- switch (code)
- {
- case GE_EXPR:
- code = GT_EXPR;
- op1 = const_binop (MINUS_EXPR, op1, integer_one_node, 0);
- break;
-
- case LT_EXPR:
- code = LE_EXPR;
- op1 = const_binop (MINUS_EXPR, op1, integer_one_node, 0);
- break;
-
- default:
- break;
- }
- }
-
- tem = fold_relational_hi_lo (&code, type, &op0, &op1);
- if (tem)
- return tem;
-
- /* Fall through. */
-
- case ORDERED_EXPR:
- case UNORDERED_EXPR:
- case UNLT_EXPR:
- case UNLE_EXPR:
- case UNGT_EXPR:
- case UNGE_EXPR:
- case UNEQ_EXPR:
- case LTGT_EXPR:
- if (!wins)
- return NULL_TREE;
-
- return fold_relational_const (code, type, op0, op1);
-
- case RANGE_EXPR:
- /* This could probably be handled. */
- return NULL_TREE;
-
- case TRUTH_AND_EXPR:
- /* If second arg is constant zero, result is zero, but first arg
- must be evaluated. */
- if (integer_zerop (op1))
- return omit_one_operand (type, op1, op0);
- /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
- case will be handled here. */
- if (integer_zerop (op0))
- return omit_one_operand (type, op0, op1);
- if (TREE_CODE (op0) == INTEGER_CST && TREE_CODE (op1) == INTEGER_CST)
- return constant_boolean_node (true, type);
- return NULL_TREE;
-
- case TRUTH_OR_EXPR:
- /* If second arg is constant true, result is true, but we must
- evaluate first arg. */
- if (TREE_CODE (op1) == INTEGER_CST && ! integer_zerop (op1))
- return omit_one_operand (type, op1, op0);
- /* Likewise for first arg, but note this only occurs here for
- TRUTH_OR_EXPR. */
- if (TREE_CODE (op0) == INTEGER_CST && ! integer_zerop (op0))
- return omit_one_operand (type, op0, op1);
- if (TREE_CODE (op0) == INTEGER_CST && TREE_CODE (op1) == INTEGER_CST)
- return constant_boolean_node (false, type);
- return NULL_TREE;
-
- case TRUTH_XOR_EXPR:
- if (TREE_CODE (op0) == INTEGER_CST && TREE_CODE (op1) == INTEGER_CST)
- {
- int x = ! integer_zerop (op0) ^ ! integer_zerop (op1);
- return constant_boolean_node (x, type);
- }
- return NULL_TREE;
-
- default:
- return NULL_TREE;
- }
+ tree tem = fold_binary (code, type, op0, op1);
+ return (tem && TREE_CONSTANT (tem)) ? tem : NULL_TREE;
}
/* Given the components of a unary expression CODE, TYPE and OP0,
tree
fold_unary_to_constant (enum tree_code code, tree type, tree op0)
{
- /* Make sure we have a suitable constant argument. */
- if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
- {
- tree subop;
-
- if (TREE_CODE (op0) == COMPLEX_CST)
- subop = TREE_REALPART (op0);
- else
- subop = op0;
-
- if (TREE_CODE (subop) != INTEGER_CST && TREE_CODE (subop) != REAL_CST)
- return NULL_TREE;
- }
-
- switch (code)
- {
- case NOP_EXPR:
- case FLOAT_EXPR:
- case CONVERT_EXPR:
- case FIX_TRUNC_EXPR:
- case FIX_FLOOR_EXPR:
- case FIX_CEIL_EXPR:
- case FIX_ROUND_EXPR:
- return fold_convert_const (code, type, op0);
-
- case NEGATE_EXPR:
- if (TREE_CODE (op0) == INTEGER_CST || TREE_CODE (op0) == REAL_CST)
- return fold_negate_const (op0, type);
- else
- return NULL_TREE;
-
- case ABS_EXPR:
- if (TREE_CODE (op0) == INTEGER_CST || TREE_CODE (op0) == REAL_CST)
- return fold_abs_const (op0, type);
- else
- return NULL_TREE;
-
- case BIT_NOT_EXPR:
- if (TREE_CODE (op0) == INTEGER_CST)
- return fold_not_const (op0, type);
- else
- return NULL_TREE;
-
- case REALPART_EXPR:
- if (TREE_CODE (op0) == COMPLEX_CST)
- return TREE_REALPART (op0);
- else
- return NULL_TREE;
-
- case IMAGPART_EXPR:
- if (TREE_CODE (op0) == COMPLEX_CST)
- return TREE_IMAGPART (op0);
- else
- return NULL_TREE;
-
- case CONJ_EXPR:
- if (TREE_CODE (op0) == COMPLEX_CST
- && TREE_CODE (TREE_TYPE (op0)) == COMPLEX_TYPE)
- return build_complex (type, TREE_REALPART (op0),
- negate_expr (TREE_IMAGPART (op0)));
- return NULL_TREE;
-
- default:
- return NULL_TREE;
- }
+ tree tem = fold_unary (code, type, op0);
+ return (tem && TREE_CONSTANT (tem)) ? tem : NULL_TREE;
}
/* If EXP represents referencing an element in a constant string
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