/* Support routines for Value Range Propagation (VRP).
- Copyright (C) 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>.
This file is part of GCC.
static int compare_values_warnv (tree val1, tree val2, bool *);
static void vrp_meet (value_range_t *, value_range_t *);
static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
- tree, tree, bool, bool *);
+ tree, tree, bool, bool *,
+ bool *);
/* Location information for ASSERT_EXPRs. Each instance of this
structure describes an ASSERT_EXPR for an SSA name. Since a single
}
+/* If abs (min) < abs (max), set VR to [-max, max], if
+ abs (min) >= abs (max), set VR to [-min, min]. */
+
+static void
+abs_extent_range (value_range_t *vr, tree min, tree max)
+{
+ int cmp;
+
+ gcc_assert (TREE_CODE (min) == INTEGER_CST);
+ gcc_assert (TREE_CODE (max) == INTEGER_CST);
+ gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
+ gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
+ min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
+ max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
+ if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ cmp = compare_values (min, max);
+ if (cmp == -1)
+ min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
+ else if (cmp == 0 || cmp == 1)
+ {
+ max = min;
+ min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
+ }
+ else
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
+}
+
+
/* Return value range information for VAR.
If we have no values ranges recorded (ie, VRP is not running), then
all should be optimized away above us. */
if ((cond_code == LT_EXPR
&& compare_values (max, min) == 0)
- || is_overflow_infinity (max))
+ || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
set_value_range_to_varying (vr_p);
else
{
all should be optimized away above us. */
if ((cond_code == GT_EXPR
&& compare_values (min, max) == 0)
- || is_overflow_infinity (min))
+ || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
set_value_range_to_varying (vr_p);
else
{
&& code != MIN_EXPR
&& code != MAX_EXPR
&& code != BIT_AND_EXPR
+ && code != BIT_IOR_EXPR
&& code != TRUTH_AND_EXPR
&& code != TRUTH_OR_EXPR)
{
/* We can still do constant propagation here. */
- if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE
- && (op1 = op_with_constant_singleton_value_range (op1)) != NULL_TREE)
+ tree const_op0 = op_with_constant_singleton_value_range (op0);
+ tree const_op1 = op_with_constant_singleton_value_range (op1);
+ if (const_op0 || const_op1)
{
- tree tem = fold_binary (code, expr_type, op0, op1);
+ tree tem = fold_binary (code, expr_type,
+ const_op0 ? const_op0 : op0,
+ const_op1 ? const_op1 : op1);
if (tem
&& is_gimple_min_invariant (tem)
&& !is_overflow_infinity (tem))
/* Refuse to operate on VARYING ranges, ranges of different kinds
and symbolic ranges. As an exception, we allow BIT_AND_EXPR
because we may be able to derive a useful range even if one of
- the operands is VR_VARYING or symbolic range. TODO, we may be
- able to derive anti-ranges in some cases. */
+ the operands is VR_VARYING or symbolic range. Similarly for
+ divisions. TODO, we may be able to derive anti-ranges in
+ some cases. */
if (code != BIT_AND_EXPR
&& code != TRUTH_AND_EXPR
&& code != TRUTH_OR_EXPR
+ && code != TRUNC_DIV_EXPR
+ && code != FLOOR_DIV_EXPR
+ && code != CEIL_DIV_EXPR
+ && code != EXACT_DIV_EXPR
+ && code != ROUND_DIV_EXPR
&& (vr0.type == VR_VARYING
|| vr1.type == VR_VARYING
|| vr0.type != vr1.type
}
}
+ else if ((code == TRUNC_DIV_EXPR
+ || code == FLOOR_DIV_EXPR
+ || code == CEIL_DIV_EXPR
+ || code == EXACT_DIV_EXPR
+ || code == ROUND_DIV_EXPR)
+ && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
+ {
+ /* For division, if op1 has VR_RANGE but op0 does not, something
+ can be deduced just from that range. Say [min, max] / [4, max]
+ gives [min / 4, max / 4] range. */
+ if (vr1.type == VR_RANGE
+ && !symbolic_range_p (&vr1)
+ && !range_includes_zero_p (&vr1))
+ {
+ vr0.type = type = VR_RANGE;
+ vr0.min = vrp_val_min (TREE_TYPE (op0));
+ vr0.max = vrp_val_max (TREE_TYPE (op1));
+ }
+ else
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ }
+
+ /* For divisions, if op0 is VR_RANGE, we can deduce a range
+ even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
+ include 0. */
+ if ((code == TRUNC_DIV_EXPR
+ || code == FLOOR_DIV_EXPR
+ || code == CEIL_DIV_EXPR
+ || code == EXACT_DIV_EXPR
+ || code == ROUND_DIV_EXPR)
+ && vr0.type == VR_RANGE
+ && (vr1.type != VR_RANGE
+ || symbolic_range_p (&vr1)
+ || range_includes_zero_p (&vr1)))
+ {
+ tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
+ int cmp;
+
+ sop = false;
+ min = NULL_TREE;
+ max = NULL_TREE;
+ if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
+ {
+ /* For unsigned division or when divisor is known
+ to be non-negative, the range has to cover
+ all numbers from 0 to max for positive max
+ and all numbers from min to 0 for negative min. */
+ cmp = compare_values (vr0.max, zero);
+ if (cmp == -1)
+ max = zero;
+ else if (cmp == 0 || cmp == 1)
+ max = vr0.max;
+ else
+ type = VR_VARYING;
+ cmp = compare_values (vr0.min, zero);
+ if (cmp == 1)
+ min = zero;
+ else if (cmp == 0 || cmp == -1)
+ min = vr0.min;
+ else
+ type = VR_VARYING;
+ }
+ else
+ {
+ /* Otherwise the range is -max .. max or min .. -min
+ depending on which bound is bigger in absolute value,
+ as the division can change the sign. */
+ abs_extent_range (vr, vr0.min, vr0.max);
+ return;
+ }
+ if (type == VR_VARYING)
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ }
+
/* Multiplications and divisions are a bit tricky to handle,
depending on the mix of signs we have in the two ranges, we
need to operate on different values to get the minimum and
(MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
MAX1) and then figure the smallest and largest values to form
the new range. */
-
- /* Divisions by zero result in a VARYING value. */
- else if (code != MULT_EXPR
- && (vr0.type == VR_ANTI_RANGE || range_includes_zero_p (&vr1)))
- {
- set_value_range_to_varying (vr);
- return;
- }
-
- /* Compute the 4 cross operations. */
- sop = false;
- val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
- if (val[0] == NULL_TREE)
- sop = true;
-
- if (vr1.max == vr1.min)
- val[1] = NULL_TREE;
else
{
- val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
- if (val[1] == NULL_TREE)
- sop = true;
- }
+ gcc_assert ((vr0.type == VR_RANGE
+ || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
+ && vr0.type == vr1.type);
- if (vr0.max == vr0.min)
- val[2] = NULL_TREE;
- else
- {
- val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
- if (val[2] == NULL_TREE)
+ /* Compute the 4 cross operations. */
+ sop = false;
+ val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
+ if (val[0] == NULL_TREE)
sop = true;
- }
- if (vr0.min == vr0.max || vr1.min == vr1.max)
- val[3] = NULL_TREE;
- else
- {
- val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
- if (val[3] == NULL_TREE)
- sop = true;
- }
+ if (vr1.max == vr1.min)
+ val[1] = NULL_TREE;
+ else
+ {
+ val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
+ if (val[1] == NULL_TREE)
+ sop = true;
+ }
- if (sop)
- {
- set_value_range_to_varying (vr);
- return;
- }
+ if (vr0.max == vr0.min)
+ val[2] = NULL_TREE;
+ else
+ {
+ val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
+ if (val[2] == NULL_TREE)
+ sop = true;
+ }
- /* Set MIN to the minimum of VAL[i] and MAX to the maximum
- of VAL[i]. */
- min = val[0];
- max = val[0];
- for (i = 1; i < 4; i++)
- {
- if (!is_gimple_min_invariant (min)
- || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
- || !is_gimple_min_invariant (max)
- || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
- break;
+ if (vr0.min == vr0.max || vr1.min == vr1.max)
+ val[3] = NULL_TREE;
+ else
+ {
+ val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
+ if (val[3] == NULL_TREE)
+ sop = true;
+ }
- if (val[i])
+ if (sop)
{
- if (!is_gimple_min_invariant (val[i])
- || (TREE_OVERFLOW (val[i])
- && !is_overflow_infinity (val[i])))
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* Set MIN to the minimum of VAL[i] and MAX to the maximum
+ of VAL[i]. */
+ min = val[0];
+ max = val[0];
+ for (i = 1; i < 4; i++)
+ {
+ if (!is_gimple_min_invariant (min)
+ || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
+ || !is_gimple_min_invariant (max)
+ || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
+ break;
+
+ if (val[i])
{
- /* If we found an overflowed value, set MIN and MAX
- to it so that we set the resulting range to
- VARYING. */
- min = max = val[i];
- break;
- }
+ if (!is_gimple_min_invariant (val[i])
+ || (TREE_OVERFLOW (val[i])
+ && !is_overflow_infinity (val[i])))
+ {
+ /* If we found an overflowed value, set MIN and MAX
+ to it so that we set the resulting range to
+ VARYING. */
+ min = max = val[i];
+ break;
+ }
- if (compare_values (val[i], min) == -1)
- min = val[i];
+ if (compare_values (val[i], min) == -1)
+ min = val[i];
- if (compare_values (val[i], max) == 1)
- max = val[i];
+ if (compare_values (val[i], max) == 1)
+ max = val[i];
+ }
}
}
}
return;
}
}
+ else if (code == BIT_IOR_EXPR)
+ {
+ if (vr0.type == VR_RANGE
+ && vr1.type == VR_RANGE
+ && TREE_CODE (vr0.min) == INTEGER_CST
+ && TREE_CODE (vr1.min) == INTEGER_CST
+ && TREE_CODE (vr0.max) == INTEGER_CST
+ && TREE_CODE (vr1.max) == INTEGER_CST
+ && tree_int_cst_sgn (vr0.min) >= 0
+ && tree_int_cst_sgn (vr1.min) >= 0)
+ {
+ double_int vr0_max = tree_to_double_int (vr0.max);
+ double_int vr1_max = tree_to_double_int (vr1.max);
+ double_int ior_max;
+
+ /* Set all bits to the right of the most significant one to 1.
+ For example, [0, 4] | [4, 4] = [4, 7]. */
+ ior_max.low = vr0_max.low | vr1_max.low;
+ ior_max.high = vr0_max.high | vr1_max.high;
+ if (ior_max.high != 0)
+ {
+ ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
+ ior_max.high |= ((HOST_WIDE_INT) 1
+ << floor_log2 (ior_max.high)) - 1;
+ }
+ else if (ior_max.low != 0)
+ ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
+ << floor_log2 (ior_max.low)) - 1;
+
+ /* Both of these endpoints are conservative. */
+ min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
+ max = double_int_to_tree (expr_type, ior_max);
+ }
+ else
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ }
else
gcc_unreachable ();
max = fold_unary_to_constant (code, type, vr0.max);
else if (!needs_overflow_infinity (type))
max = TYPE_MAX_VALUE (type);
- else if (supports_overflow_infinity (type))
+ else if (supports_overflow_infinity (type)
+ /* We shouldn't generate [+INF, +INF] as set_value_range
+ doesn't like this and ICEs. */
+ && !is_positive_overflow_infinity (min))
max = positive_overflow_infinity (type);
else
{
bool sop = false;
tree val;
- val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop);
+ val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
+ NULL);
/* A disadvantage of using a special infinity as an overflow
representation is that we lose the ability to record overflow
&& gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
#endif
+ /* Never build an assert comparing against an integer constant with
+ TREE_OVERFLOW set. This confuses our undefined overflow warning
+ machinery. */
+ if (TREE_CODE (val) == INTEGER_CST
+ && TREE_OVERFLOW (val))
+ val = build_int_cst_wide (TREE_TYPE (val),
+ TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
+
/* The new assertion A will be inserted at BB or E. We need to
determine if the new location is dominated by a previously
registered location for A. If we are doing an edge insertion,
edge e;
tree vec2;
size_t n = gimple_switch_num_labels(last);
+#if GCC_VERSION >= 4000
unsigned int idx;
+#else
+ /* Work around GCC 3.4 bug (PR 37086). */
+ volatile unsigned int idx;
+#endif
need_assert = false;
bsi = gsi_for_stmt (last);
return NULL_TREE;
}
+/* Helper function for vrp_evaluate_conditional_warnv. */
+
+static tree
+vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
+ tree op0, tree op1,
+ bool * strict_overflow_p)
+{
+ value_range_t *vr0, *vr1;
+
+ vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
+ vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
+
+ if (vr0 && vr1)
+ return compare_ranges (code, vr0, vr1, strict_overflow_p);
+ else if (vr0 && vr1 == NULL)
+ return compare_range_with_value (code, vr0, op1, strict_overflow_p);
+ else if (vr0 == NULL && vr1)
+ return (compare_range_with_value
+ (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
+ return NULL;
+}
+
/* Helper function for vrp_evaluate_conditional_warnv. */
static tree
vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
tree op1, bool use_equiv_p,
- bool *strict_overflow_p)
+ bool *strict_overflow_p, bool *only_ranges)
{
+ tree ret;
+ if (only_ranges)
+ *only_ranges = true;
+
/* We only deal with integral and pointer types. */
if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
&& !POINTER_TYPE_P (TREE_TYPE (op0)))
if (use_equiv_p)
{
+ if (only_ranges
+ && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
+ (code, op0, op1, strict_overflow_p)))
+ return ret;
+ *only_ranges = false;
if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
return compare_names (code, op0, op1, strict_overflow_p);
else if (TREE_CODE (op0) == SSA_NAME)
(swap_tree_comparison (code), op1, op0, strict_overflow_p));
}
else
- {
- value_range_t *vr0, *vr1;
-
- vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
- vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
-
- if (vr0 && vr1)
- return compare_ranges (code, vr0, vr1, strict_overflow_p);
- else if (vr0 && vr1 == NULL)
- return compare_range_with_value (code, vr0, op1, strict_overflow_p);
- else if (vr0 == NULL && vr1)
- return (compare_range_with_value
- (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
- }
+ return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
+ strict_overflow_p);
return NULL_TREE;
}
{
bool sop;
tree ret;
+ bool only_ranges;
sop = false;
- ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop);
+ ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
+ &only_ranges);
if (ret && sop)
{
}
if (warn_type_limits
- && ret
+ && ret && only_ranges
&& TREE_CODE_CLASS (code) == tcc_comparison
&& TREE_CODE (op0) == SSA_NAME)
{
val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
gimple_cond_lhs (stmt),
gimple_cond_rhs (stmt),
- false, &sop);
+ false, &sop, NULL);
if (val)
{
if (!sop)
minimums. */
if (cmp_min > 0 || cmp_min < 0)
{
- /* If we will end up with a (-INF, +INF) range, set it
- to VARYING. */
- if (vrp_val_is_max (vr_result.max))
+ /* If we will end up with a (-INF, +INF) range, set it to
+ VARYING. Same if the previous max value was invalid for
+ the type and we'd end up with vr_result.min > vr_result.max. */
+ if (vrp_val_is_max (vr_result.max)
+ || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
+ vr_result.max) > 0)
goto varying;
if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
the previous one, go all the way to +INF. */
if (cmp_max < 0 || cmp_max > 0)
{
- /* If we will end up with a (-INF, +INF) range, set it
- to VARYING. */
- if (vrp_val_is_min (vr_result.min))
+ /* If we will end up with a (-INF, +INF) range, set it to
+ VARYING. Same if the previous min value was invalid for
+ the type and we'd end up with vr_result.max < vr_result.min. */
+ if (vrp_val_is_min (vr_result.min)
+ || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
+ vr_result.min) < 0)
goto varying;
if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
return SSA_PROP_VARYING;
}
+/* Simplify boolean operations if the source is known
+ to be already a boolean. */
+static bool
+simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
+{
+ enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
+ tree val = NULL;
+ tree op0, op1;
+ value_range_t *vr;
+ bool sop = false;
+ bool need_conversion;
+
+ op0 = gimple_assign_rhs1 (stmt);
+ if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
+ {
+ if (TREE_CODE (op0) != SSA_NAME)
+ return false;
+ vr = get_value_range (op0);
+
+ val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
+ if (!val || !integer_onep (val))
+ return false;
+
+ val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
+ if (!val || !integer_onep (val))
+ return false;
+ }
+
+ if (rhs_code == TRUTH_NOT_EXPR)
+ {
+ rhs_code = NE_EXPR;
+ op1 = build_int_cst (TREE_TYPE (op0), 1);
+ }
+ else
+ {
+ op1 = gimple_assign_rhs2 (stmt);
+
+ /* Reduce number of cases to handle. */
+ if (is_gimple_min_invariant (op1))
+ {
+ /* Exclude anything that should have been already folded. */
+ if (rhs_code != EQ_EXPR
+ && rhs_code != NE_EXPR
+ && rhs_code != TRUTH_XOR_EXPR)
+ return false;
+
+ if (!integer_zerop (op1)
+ && !integer_onep (op1)
+ && !integer_all_onesp (op1))
+ return false;
+
+ /* Limit the number of cases we have to consider. */
+ if (rhs_code == EQ_EXPR)
+ {
+ rhs_code = NE_EXPR;
+ op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
+ }
+ }
+ else
+ {
+ /* Punt on A == B as there is no BIT_XNOR_EXPR. */
+ if (rhs_code == EQ_EXPR)
+ return false;
+
+ if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
+ {
+ vr = get_value_range (op1);
+ val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
+ if (!val || !integer_onep (val))
+ return false;
+
+ val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
+ if (!val || !integer_onep (val))
+ return false;
+ }
+ }
+ }
+
+ if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
+ {
+ location_t location;
+
+ if (!gimple_has_location (stmt))
+ location = input_location;
+ else
+ location = gimple_location (stmt);
+
+ if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
+ warning_at (location, OPT_Wstrict_overflow,
+ _("assuming signed overflow does not occur when "
+ "simplifying && or || to & or |"));
+ else
+ warning_at (location, OPT_Wstrict_overflow,
+ _("assuming signed overflow does not occur when "
+ "simplifying ==, != or ! to identity or ^"));
+ }
+
+ need_conversion =
+ !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
+ TREE_TYPE (op0));
+
+ /* Make sure to not sign-extend -1 as a boolean value. */
+ if (need_conversion
+ && !TYPE_UNSIGNED (TREE_TYPE (op0))
+ && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
+ return false;
+
+ switch (rhs_code)
+ {
+ case TRUTH_AND_EXPR:
+ rhs_code = BIT_AND_EXPR;
+ break;
+ case TRUTH_OR_EXPR:
+ rhs_code = BIT_IOR_EXPR;
+ break;
+ case TRUTH_XOR_EXPR:
+ case NE_EXPR:
+ if (integer_zerop (op1))
+ {
+ gimple_assign_set_rhs_with_ops (gsi,
+ need_conversion ? NOP_EXPR : SSA_NAME,
+ op0, NULL);
+ update_stmt (gsi_stmt (*gsi));
+ return true;
+ }
+
+ rhs_code = BIT_XOR_EXPR;
+ break;
+ default:
+ gcc_unreachable ();
+ }
+
+ if (need_conversion)
+ return false;
+
+ gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
+ update_stmt (gsi_stmt (*gsi));
+ return true;
+}
+
/* Simplify a division or modulo operator to a right shift or
bitwise and if the first operand is unsigned or is greater
than zero and the second operand is an exact power of two. */
-static void
+static bool
simplify_div_or_mod_using_ranges (gimple stmt)
{
enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
}
update_stmt (stmt);
+ return true;
}
+
+ return false;
}
/* If the operand to an ABS_EXPR is >= 0, then eliminate the
ABS_EXPR. If the operand is <= 0, then simplify the
ABS_EXPR into a NEGATE_EXPR. */
-static void
+static bool
simplify_abs_using_ranges (gimple stmt)
{
tree val = NULL;
else
gimple_assign_set_rhs_code (stmt, SSA_NAME);
update_stmt (stmt);
+ return true;
}
}
+
+ return false;
}
/* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
test if the range information indicates only one value can satisfy
the original conditional. */
-static void
+static bool
simplify_cond_using_ranges (gimple stmt)
{
tree op0 = gimple_cond_lhs (stmt);
print_gimple_stmt (dump_file, stmt, 0, 0);
fprintf (dump_file, "\n");
}
- return;
+ return true;
}
/* Try again after inverting the condition. We only deal
print_gimple_stmt (dump_file, stmt, 0, 0);
fprintf (dump_file, "\n");
}
- return;
+ return true;
}
}
}
+
+ return false;
}
/* Simplify a switch statement using the value range of the switch
argument. */
-static void
+static bool
simplify_switch_using_ranges (gimple stmt)
{
tree op = gimple_switch_index (stmt);
switch_update su;
if (TREE_CODE (op) != SSA_NAME)
- return;
+ return false;
vr = get_value_range (op);
/* We can only handle integer ranges. */
if (vr->type != VR_RANGE
|| symbolic_range_p (vr))
- return;
+ return false;
/* Find case label for min/max of the value range. */
n = gimple_switch_num_labels (stmt);
if (i == 1
&& j == n - 1
&& take_default)
- return;
+ return false;
/* Build a new vector of taken case labels. */
vec2 = make_tree_vec (j - i + 1 + (int)take_default);
su.stmt = stmt;
su.vec = vec2;
VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
+ return false;
}
/* Simplify STMT using ranges if possible. */
-void
-simplify_stmt_using_ranges (gimple stmt)
+bool
+simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
{
+ gimple stmt = gsi_stmt (*gsi);
if (is_gimple_assign (stmt))
{
enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
+ switch (rhs_code)
+ {
+ case EQ_EXPR:
+ case NE_EXPR:
+ case TRUTH_NOT_EXPR:
+ case TRUTH_AND_EXPR:
+ case TRUTH_OR_EXPR:
+ case TRUTH_XOR_EXPR:
+ /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
+ or identity if the RHS is zero or one, and the LHS are known
+ to be boolean values. Transform all TRUTH_*_EXPR into
+ BIT_*_EXPR if both arguments are known to be boolean values. */
+ if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
+ return simplify_truth_ops_using_ranges (gsi, stmt);
+ break;
+
/* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
and BIT_AND_EXPR respectively if the first operand is greater
than zero and the second operand is an exact power of two. */
- if ((rhs_code == TRUNC_DIV_EXPR || rhs_code == TRUNC_MOD_EXPR)
- && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
- && integer_pow2p (gimple_assign_rhs2 (stmt)))
- simplify_div_or_mod_using_ranges (stmt);
+ case TRUNC_DIV_EXPR:
+ case TRUNC_MOD_EXPR:
+ if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
+ && integer_pow2p (gimple_assign_rhs2 (stmt)))
+ return simplify_div_or_mod_using_ranges (stmt);
+ break;
/* Transform ABS (X) into X or -X as appropriate. */
- if (rhs_code == ABS_EXPR
- && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
- && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
- simplify_abs_using_ranges (stmt);
+ case ABS_EXPR:
+ if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
+ && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
+ return simplify_abs_using_ranges (stmt);
+ break;
+
+ default:
+ break;
+ }
}
else if (gimple_code (stmt) == GIMPLE_COND)
- simplify_cond_using_ranges (stmt);
+ return simplify_cond_using_ranges (stmt);
else if (gimple_code (stmt) == GIMPLE_SWITCH)
- simplify_switch_using_ranges (stmt);
+ return simplify_switch_using_ranges (stmt);
+
+ return false;
}
/* Stack of dest,src equivalency pairs that need to be restored after
{
size_t j;
size_t n = TREE_VEC_LENGTH (su->vec);
+ tree label;
gimple_switch_set_num_labels (su->stmt, n);
for (j = 0; j < n; j++)
gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
+ /* As we may have replaced the default label with a regular one
+ make sure to make it a real default label again. This ensures
+ optimal expansion. */
+ label = gimple_switch_default_label (su->stmt);
+ CASE_LOW (label) = NULL_TREE;
+ CASE_HIGH (label) = NULL_TREE;
}
if (VEC_length (edge, to_remove_edges) > 0)
OSDN Git Service
