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
fold_convert (unsigned_type, rhs),
size_int (lbitsize), 0)))
{
- warning ("comparison is always %d due to width of bit-field",
+ warning (0, "comparison is always %d due to width of bit-field",
code == NE_EXPR);
return constant_boolean_node (code == NE_EXPR, compare_type);
}
size_int (lbitsize - 1), 0);
if (! integer_zerop (tem) && ! integer_all_onesp (tem))
{
- warning ("comparison is always %d due to width of bit-field",
+ warning (0, "comparison is always %d due to width of bit-field",
code == NE_EXPR);
return constant_boolean_node (code == NE_EXPR, compare_type);
}
lntype, ll_mask),
0)))
{
- warning ("comparison is always %d", wanted_code == NE_EXPR);
+ warning (0, "comparison is always %d", wanted_code == NE_EXPR);
return constant_boolean_node (wanted_code == NE_EXPR, truth_type);
}
lntype, rl_mask),
0)))
{
- warning ("comparison is always %d", wanted_code == NE_EXPR);
+ warning (0, "comparison is always %d", wanted_code == NE_EXPR);
return constant_boolean_node (wanted_code == NE_EXPR, truth_type);
}
{
if (wanted_code == NE_EXPR)
{
- warning ("%<or%> of unmatched not-equal tests is always 1");
+ warning (0, "%<or%> of unmatched not-equal tests is always 1");
return constant_boolean_node (true, truth_type);
}
else
{
- warning ("%<and%> of mutually exclusive equal-tests is always 0");
+ warning (
0, "%<and%> of mutually exclusive equal-tests is always 0");
return constant_boolean_node (false, truth_type);
}
}
/* If CODE with arguments ARG0 and ARG1 represents a single bit
- equality/inequality test, then return a simplified form of
- the test using shifts and logical operations. Otherwise return
- NULL. TYPE is the desired result type. */
+ equality/inequality test, then return a simplified form of the test
+ using a sign testing. Otherwise return NULL. TYPE is the desired
+ result type. */
-tree
-fold_single_bit_test (enum tree_code code, tree arg0, tree arg1,
- tree result_type)
+static tree
+fold_single_bit_test_into_sign_test (enum tree_code code, tree arg0, tree arg1,
+ tree result_type)
{
/* If this is testing a single bit, we can optimize the test. */
if ((code == NE_EXPR || code == EQ_EXPR)
&& TREE_CODE (arg0) == BIT_AND_EXPR && integer_zerop (arg1)
&& integer_pow2p (TREE_OPERAND (arg0, 1)))
{
- tree inner = TREE_OPERAND (arg0, 0);
- tree type = TREE_TYPE (arg0);
- int bitnum = tree_log2 (TREE_OPERAND (arg0, 1));
- enum machine_mode operand_mode = TYPE_MODE (type);
- int ops_unsigned;
- tree signed_type, unsigned_type, intermediate_type;
- tree arg00;
-
/* If we have (A & C) != 0 where C is the sign bit of A, convert
this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
- arg00 = sign_bit_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg0, 1));
+ tree arg00 = sign_bit_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg0, 1));
+
if (arg00 != NULL_TREE
/* This is only a win if casting to a signed type is cheap,
i.e. when arg00's type is not a partial mode. */
result_type, fold_convert (stype, arg00),
fold_convert (stype, integer_zero_node));
}
+ }
+
+ return NULL_TREE;
+}
+
+/* If CODE with arguments ARG0 and ARG1 represents a single bit
+ equality/inequality test, then return a simplified form of
+ the test using shifts and logical operations. Otherwise return
+ NULL. TYPE is the desired result type. */
+
+tree
+fold_single_bit_test (enum tree_code code, tree arg0, tree arg1,
+ tree result_type)
+{
+ /* If this is testing a single bit, we can optimize the test. */
+ if ((code == NE_EXPR || code == EQ_EXPR)
+ && TREE_CODE (arg0) == BIT_AND_EXPR && integer_zerop (arg1)
+ && integer_pow2p (TREE_OPERAND (arg0, 1)))
+ {
+ tree inner = TREE_OPERAND (arg0, 0);
+ tree type = TREE_TYPE (arg0);
+ int bitnum = tree_log2 (TREE_OPERAND (arg0, 1));
+ enum machine_mode operand_mode = TYPE_MODE (type);
+ int ops_unsigned;
+ tree signed_type, unsigned_type, intermediate_type;
+ tree tem;
+
+ /* First, see if we can fold the single bit test into a sign-bit
+ test. */
+ tem = fold_single_bit_test_into_sign_test (code, arg0, arg1,
+ result_type);
+ if (tem)
+ return tem;
/* Otherwise we have (A & C) != 0 where C is a single bit,
convert that into ((A >> C2) & 1). Where C2 = log2(C).
|| TYPE_UNSIGNED (TREE_TYPE (arg0)) == TYPE_UNSIGNED (shorter_type))
&& (TREE_TYPE (arg1_unw) == shorter_type
|| (TREE_CODE (arg1_unw) == INTEGER_CST
- && TREE_CODE (shorter_type) == INTEGER_TYPE
+ && (TREE_CODE (shorter_type) == INTEGER_TYPE
+ || TREE_CODE (shorter_type) == BOOLEAN_TYPE)
&& int_fits_type_p (arg1_unw, shorter_type))))
return fold_build2 (code, type, arg0_unw,
fold_convert (shorter_type, arg1_unw));
OP0. Return the folded expression if folding is successful.
Otherwise, return NULL_TREE. */
-static tree
+tree
fold_unary (enum tree_code code, tree type, tree op0)
{
tree tem;
|| (TREE_CODE (arg0) == PLUS_EXPR
&& integer_all_onesp (TREE_OPERAND (arg0, 1)))))
return fold_build1 (NEGATE_EXPR, type, TREE_OPERAND (arg0, 0));
+ /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
+ else if (TREE_CODE (arg0) == BIT_XOR_EXPR
+ && (tem = fold_unary (BIT_NOT_EXPR, type,
+ fold_convert (type,
+ TREE_OPERAND (arg0, 0)))))
+ return fold_build2 (BIT_XOR_EXPR, type, tem,
+ fold_convert (type, TREE_OPERAND (arg0, 1)));
+ else if (TREE_CODE (arg0) == BIT_XOR_EXPR
+ && (tem = fold_unary (BIT_NOT_EXPR, type,
+ fold_convert (type,
+ TREE_OPERAND (arg0, 1)))))
+ return fold_build2 (BIT_XOR_EXPR, type,
+ fold_convert (type, TREE_OPERAND (arg0, 0)), tem);
+
return NULL_TREE;
case TRUTH_NOT_EXPR:
OP0 and OP1. Return the folded expression if folding is
successful. Otherwise, return NULL_TREE. */
-static tree
+tree
fold_binary (enum tree_code code, tree type, tree op0, tree op1)
{
tree t1 = NULL_TREE;
case PLUS_EXPR:
/* A + (-B) -> A - B */
if (TREE_CODE (arg1) == NEGATE_EXPR)
- return fold_build2 (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0));
+ return fold_build2 (MINUS_EXPR, type,
+ fold_convert (type, arg0),
+ fold_convert (type, TREE_OPERAND (arg1, 0)));
/* (-A) + B -> B - A */
if (TREE_CODE (arg0) == NEGATE_EXPR
&& reorder_operands_p (TREE_OPERAND (arg0, 0), arg1))
- return fold_build2 (MINUS_EXPR, type, arg1, TREE_OPERAND (arg0, 0));
+ return fold_build2 (MINUS_EXPR, type,
+ fold_convert (type, arg1),
+ fold_convert (type, TREE_OPERAND (arg0, 0)));
/* Convert ~A + 1 to -A. */
if (INTEGRAL_TYPE_P (type)
&& TREE_CODE (arg0) == BIT_NOT_EXPR
fold_build2 (PLUS_EXPR, type,
fold_convert (type, alt0),
fold_convert (type, alt1)),
- same);
+ fold_convert (type, same));
}
/* Try replacing &a[i1] + c * i2 with &a[i1 + i2], if c is step
&& ptr_difference_const (arg0, arg1, &diff))
return build_int_cst_type (type, diff);
}
-
+
+ /* Fold &a[i] - &a[j] to i-j. */
+ if (TREE_CODE (arg0) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (arg0, 0)) == ARRAY_REF
+ && TREE_CODE (arg1) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (arg1, 0)) == ARRAY_REF)
+ {
+ tree aref0 = TREE_OPERAND (arg0, 0);
+ tree aref1 = TREE_OPERAND (arg1, 0);
+ if (operand_equal_p (TREE_OPERAND (aref0, 0),
+ TREE_OPERAND (aref1, 0), 0))
+ {
+ tree op0 = fold_convert (type, TREE_OPERAND (aref0, 1));
+ tree op1 = fold_convert (type, TREE_OPERAND (aref1, 1));
+ tree esz = array_ref_element_size (aref0);
+ tree diff = build2 (MINUS_EXPR, type, op0, op1);
+ return fold_build2 (MULT_EXPR, type, diff,
+ fold_convert (type, esz));
+
+ }
+ }
+
/* Try replacing &a[i1] - c * i2 with &a[i1 - i2], if c is step
of the array. Loop optimizer sometimes produce this type of
expressions. */
goto bit_ior;
}
+ /* Convert ~X ^ ~Y to X ^ Y. */
+ if (TREE_CODE (arg0) == BIT_NOT_EXPR
+ && TREE_CODE (arg1) == BIT_NOT_EXPR)
+ return fold_build2 (code, type,
+ fold_convert (type, TREE_OPERAND (arg0, 0)),
+ fold_convert (type, TREE_OPERAND (arg1, 0)));
+
/* See if this can be simplified into a rotate first. If that
is unsuccessful continue in the association code. */
goto bit_rotate;
if (code == TRUNC_MOD_EXPR
&& !TYPE_UNSIGNED (type)
&& TREE_CODE (arg1) == INTEGER_CST
+ && !TREE_CONSTANT_OVERFLOW (arg1)
&& TREE_INT_CST_HIGH (arg1) < 0
&& !flag_trapv
/* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
case LT_EXPR:
case GT_EXPR:
case LE_EXPR:
- case GE_EXPR:
+ case GE_EXPR:
/* If one arg is a real or integer constant, put it last. */
if (tree_swap_operands_p (arg0, arg1, true))
- return fold_build2 (swap_tree_comparison (code), type, arg1, arg0);
+ return fold_build2 (swap_tree_comparison (code), type, op1, op0);
+
+ /* bool_var != 0 becomes bool_var. */
+ if (TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE && integer_zerop (arg1)
+ && code == NE_EXPR)
+ return non_lvalue (fold_convert (type, arg0));
+
+ /* bool_var == 1 becomes bool_var. */
+ if (TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE && integer_onep (arg1)
+ && code == EQ_EXPR)
+ return non_lvalue (fold_convert (type, arg0));
/* If this is an equality comparison of the address of a non-weak
object against zero, then we know the result. */
}
}
+ /* Transform comparisons of the form X +- C CMP X. */
+ if ((code != EQ_EXPR && code != NE_EXPR)
+ && (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
+ && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)
+ && ((TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST
+ && !HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0))))
+ || (TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
+ && !TYPE_UNSIGNED (TREE_TYPE (arg1))
+ && !(flag_wrapv || flag_trapv))))
+ {
+ tree arg01 = TREE_OPERAND (arg0, 1);
+ enum tree_code code0 = TREE_CODE (arg0);
+ int is_positive;
+
+ if (TREE_CODE (arg01) == REAL_CST)
+ is_positive = REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg01)) ? -1 : 1;
+ else
+ is_positive = tree_int_cst_sgn (arg01);
+
+ /* (X - c) > X becomes false. */
+ if (code == GT_EXPR
+ && ((code0 == MINUS_EXPR && is_positive >= 0)
+ || (code0 == PLUS_EXPR && is_positive <= 0)))
+ return constant_boolean_node (0, type);
+
+ /* Likewise (X + c) < X becomes false. */
+ if (code == LT_EXPR
+ && ((code0 == PLUS_EXPR && is_positive >= 0)
+ || (code0 == MINUS_EXPR && is_positive <= 0)))
+ return constant_boolean_node (0, type);
+
+ /* Convert (X - c) <= X to true. */
+ if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1)))
+ && code == LE_EXPR
+ && ((code0 == MINUS_EXPR && is_positive >= 0)
+ || (code0 == PLUS_EXPR && is_positive <= 0)))
+ return constant_boolean_node (1, type);
+
+ /* Convert (X + c) >= X to true. */
+ if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1)))
+ && code == GE_EXPR
+ && ((code0 == PLUS_EXPR && is_positive >= 0)
+ || (code0 == MINUS_EXPR && is_positive <= 0)))
+ return constant_boolean_node (1, type);
+
+ if (TREE_CODE (arg01) == INTEGER_CST)
+ {
+ /* Convert X + c > X and X - c < X to true for integers. */
+ if (code == GT_EXPR
+ && ((code0 == PLUS_EXPR && is_positive > 0)
+ || (code0 == MINUS_EXPR && is_positive < 0)))
+ return constant_boolean_node (1, type);
+
+ if (code == LT_EXPR
+ && ((code0 == MINUS_EXPR && is_positive > 0)
+ || (code0 == PLUS_EXPR && is_positive < 0)))
+ return constant_boolean_node (1, type);
+
+ /* Convert X + c <= X and X - c >= X to false for integers. */
+ if (code == LE_EXPR
+ && ((code0 == PLUS_EXPR && is_positive > 0)
+ || (code0 == MINUS_EXPR && is_positive < 0)))
+ return constant_boolean_node (0, type);
+
+ if (code == GE_EXPR
+ && ((code0 == MINUS_EXPR && is_positive > 0)
+ || (code0 == PLUS_EXPR && is_positive < 0)))
+ return constant_boolean_node (0, type);
+ }
+ }
+
if (FLOAT_TYPE_P (TREE_TYPE (arg0)))
{
tree targ0 = strip_float_extensions (arg0);
}
/* 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)));
arg0, fold_convert (TREE_TYPE (arg0),
integer_zero_node));
- /* If we have (A & C) != 0 or (A & C) == 0 and C is a power of
- 2, then fold the expression into shifts and logical operations. */
- tem = fold_single_bit_test (code, arg0, arg1, type);
+ /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
+ bit, then fold the expression into A < 0 or A >= 0. */
+ tem = fold_single_bit_test_into_sign_test (code, arg0, arg1, type);
if (tem)
return tem;
return t1;
}
+ /* Fold a comparison of the address of COMPONENT_REFs with the same
+ type and component to a comparison of the address of the base
+ object. In short, &x->a OP &y->a to x OP y and
+ &x->a OP &y.a to x OP &y */
+ if (TREE_CODE (arg0) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (arg0, 0)) == COMPONENT_REF
+ && TREE_CODE (arg1) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (arg1, 0)) == COMPONENT_REF)
+ {
+ tree cref0 = TREE_OPERAND (arg0, 0);
+ tree cref1 = TREE_OPERAND (arg1, 0);
+ if (TREE_OPERAND (cref0, 1) == TREE_OPERAND (cref1, 1))
+ {
+ tree op0 = TREE_OPERAND (cref0, 0);
+ tree op1 = TREE_OPERAND (cref1, 0);
+ return fold_build2 (code, type,
+ build_fold_addr_expr (op0),
+ build_fold_addr_expr (op1));
+ }
+ }
+
/* If this is a comparison of complex values and either or both sides
are a COMPLEX_EXPR or COMPLEX_CST, it is best to split up the
comparisons and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR.
return build_complex (type, arg0, arg1);
return NULL_TREE;
+ case ASSERT_EXPR:
+ /* An ASSERT_EXPR should never be passed to fold_binary. */
+ gcc_unreachable ();
+
default:
return NULL_TREE;
} /* switch (code) */
OP0, OP1, and OP2. Return the folded expression if folding is
successful. Otherwise, return NULL_TREE. */
-static tree
+tree
fold_ternary (enum tree_code code, tree type, tree op0, tree op1, tree op2)
{
tree tem;
case CONST_DECL:
return fold (DECL_INITIAL (t));
- case ASSERT_EXPR:
- {
- /* Given ASSERT_EXPR <Y, COND>, return Y if COND can be folded
- to boolean_true_node. If COND folds to boolean_false_node,
- return ASSERT_EXPR <Y, 0>. Otherwise, return the original
- expression. */
- tree c = fold (ASSERT_EXPR_COND (t));
- if (c == boolean_true_node)
- return ASSERT_EXPR_VAR (t);
- else if (c == boolean_false_node)
- return build (ASSERT_EXPR, TREE_TYPE (t), ASSERT_EXPR_VAR (t), c);
- else
- return t;
- }
-
default:
return t;
} /* switch (code) */
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.
If the expression could be simplified to a constant, then return
the constant. If the expression would not be simplified to a
- constant, then return NULL_TREE.
-
- Note this is primarily designed to be called after gimplification
- of the tree structures and when at least one operand is a constant.
- As a result of those simplifying assumptions this routine is far
- simpler than the generic fold routine. */
+ constant, then return NULL_TREE. */
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,
If the expression could be simplified to a constant, then return
the constant. If the expression would not be simplified to a
- constant, then return NULL_TREE.
-
- Note this is primarily designed to be called after gimplification
- of the tree structures and when op0 is a constant. As a result
- of those simplifying assumptions this routine is far simpler than
- the generic fold routine. */
+ constant, then return NULL_TREE. */
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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