| /* Support routines for Value Range Propagation (VRP). |
| Copyright (C) 2005-2021 Free Software Foundation, Inc. |
| Contributed by Diego Novillo <dnovillo@redhat.com>. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3, or (at your option) |
| any later version. |
| |
| GCC is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "basic-block.h" |
| #include "bitmap.h" |
| #include "sbitmap.h" |
| #include "options.h" |
| #include "dominance.h" |
| #include "function.h" |
| #include "cfg.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "tree-pass.h" |
| #include "ssa.h" |
| #include "gimple-pretty-print.h" |
| #include "fold-const.h" |
| #include "cfganal.h" |
| #include "gimple-iterator.h" |
| #include "tree-cfg.h" |
| #include "tree-ssa-loop-manip.h" |
| #include "tree-ssa-loop-niter.h" |
| #include "tree-into-ssa.h" |
| #include "cfgloop.h" |
| #include "tree-scalar-evolution.h" |
| #include "tree-ssa-propagate.h" |
| #include "tree-ssa-threadedge.h" |
| #include "domwalk.h" |
| #include "vr-values.h" |
| #include "gimple-array-bounds.h" |
| #include "gimple-range.h" |
| #include "gimple-range-path.h" |
| #include "value-pointer-equiv.h" |
| #include "gimple-fold.h" |
| |
| /* Set of SSA names found live during the RPO traversal of the function |
| for still active basic-blocks. */ |
| class live_names |
| { |
| public: |
| live_names (); |
| ~live_names (); |
| void set (tree, basic_block); |
| void clear (tree, basic_block); |
| void merge (basic_block dest, basic_block src); |
| bool live_on_block_p (tree, basic_block); |
| bool live_on_edge_p (tree, edge); |
| bool block_has_live_names_p (basic_block); |
| void clear_block (basic_block); |
| |
| private: |
| sbitmap *live; |
| unsigned num_blocks; |
| void init_bitmap_if_needed (basic_block); |
| }; |
| |
| void |
| live_names::init_bitmap_if_needed (basic_block bb) |
| { |
| unsigned i = bb->index; |
| if (!live[i]) |
| { |
| live[i] = sbitmap_alloc (num_ssa_names); |
| bitmap_clear (live[i]); |
| } |
| } |
| |
| bool |
| live_names::block_has_live_names_p (basic_block bb) |
| { |
| unsigned i = bb->index; |
| return live[i] && bitmap_empty_p (live[i]); |
| } |
| |
| void |
| live_names::clear_block (basic_block bb) |
| { |
| unsigned i = bb->index; |
| if (live[i]) |
| { |
| sbitmap_free (live[i]); |
| live[i] = NULL; |
| } |
| } |
| |
| void |
| live_names::merge (basic_block dest, basic_block src) |
| { |
| init_bitmap_if_needed (dest); |
| init_bitmap_if_needed (src); |
| bitmap_ior (live[dest->index], live[dest->index], live[src->index]); |
| } |
| |
| void |
| live_names::set (tree name, basic_block bb) |
| { |
| init_bitmap_if_needed (bb); |
| bitmap_set_bit (live[bb->index], SSA_NAME_VERSION (name)); |
| } |
| |
| void |
| live_names::clear (tree name, basic_block bb) |
| { |
| unsigned i = bb->index; |
| if (live[i]) |
| bitmap_clear_bit (live[i], SSA_NAME_VERSION (name)); |
| } |
| |
| live_names::live_names () |
| { |
| num_blocks = last_basic_block_for_fn (cfun); |
| live = XCNEWVEC (sbitmap, num_blocks); |
| } |
| |
| live_names::~live_names () |
| { |
| for (unsigned i = 0; i < num_blocks; ++i) |
| if (live[i]) |
| sbitmap_free (live[i]); |
| XDELETEVEC (live); |
| } |
| |
| bool |
| live_names::live_on_block_p (tree name, basic_block bb) |
| { |
| return (live[bb->index] |
| && bitmap_bit_p (live[bb->index], SSA_NAME_VERSION (name))); |
| } |
| |
| /* Return true if the SSA name NAME is live on the edge E. */ |
| |
| bool |
| live_names::live_on_edge_p (tree name, edge e) |
| { |
| return live_on_block_p (name, e->dest); |
| } |
| |
| |
| /* VR_TYPE describes a range with mininum value *MIN and maximum |
| value *MAX. Restrict the range to the set of values that have |
| no bits set outside NONZERO_BITS. Update *MIN and *MAX and |
| return the new range type. |
| |
| SGN gives the sign of the values described by the range. */ |
| |
| enum value_range_kind |
| intersect_range_with_nonzero_bits (enum value_range_kind vr_type, |
| wide_int *min, wide_int *max, |
| const wide_int &nonzero_bits, |
| signop sgn) |
| { |
| if (vr_type == VR_ANTI_RANGE) |
| { |
| /* The VR_ANTI_RANGE is equivalent to the union of the ranges |
| A: [-INF, *MIN) and B: (*MAX, +INF]. First use NONZERO_BITS |
| to create an inclusive upper bound for A and an inclusive lower |
| bound for B. */ |
| wide_int a_max = wi::round_down_for_mask (*min - 1, nonzero_bits); |
| wide_int b_min = wi::round_up_for_mask (*max + 1, nonzero_bits); |
| |
| /* If the calculation of A_MAX wrapped, A is effectively empty |
| and A_MAX is the highest value that satisfies NONZERO_BITS. |
| Likewise if the calculation of B_MIN wrapped, B is effectively |
| empty and B_MIN is the lowest value that satisfies NONZERO_BITS. */ |
| bool a_empty = wi::ge_p (a_max, *min, sgn); |
| bool b_empty = wi::le_p (b_min, *max, sgn); |
| |
| /* If both A and B are empty, there are no valid values. */ |
| if (a_empty && b_empty) |
| return VR_UNDEFINED; |
| |
| /* If exactly one of A or B is empty, return a VR_RANGE for the |
| other one. */ |
| if (a_empty || b_empty) |
| { |
| *min = b_min; |
| *max = a_max; |
| gcc_checking_assert (wi::le_p (*min, *max, sgn)); |
| return VR_RANGE; |
| } |
| |
| /* Update the VR_ANTI_RANGE bounds. */ |
| *min = a_max + 1; |
| *max = b_min - 1; |
| gcc_checking_assert (wi::le_p (*min, *max, sgn)); |
| |
| /* Now check whether the excluded range includes any values that |
| satisfy NONZERO_BITS. If not, switch to a full VR_RANGE. */ |
| if (wi::round_up_for_mask (*min, nonzero_bits) == b_min) |
| { |
| unsigned int precision = min->get_precision (); |
| *min = wi::min_value (precision, sgn); |
| *max = wi::max_value (precision, sgn); |
| vr_type = VR_RANGE; |
| } |
| } |
| if (vr_type == VR_RANGE || vr_type == VR_VARYING) |
| { |
| *max = wi::round_down_for_mask (*max, nonzero_bits); |
| |
| /* Check that the range contains at least one valid value. */ |
| if (wi::gt_p (*min, *max, sgn)) |
| return VR_UNDEFINED; |
| |
| *min = wi::round_up_for_mask (*min, nonzero_bits); |
| gcc_checking_assert (wi::le_p (*min, *max, sgn)); |
| } |
| return vr_type; |
| } |
| |
| /* Return true if max and min of VR are INTEGER_CST. It's not necessary |
| a singleton. */ |
| |
| bool |
| range_int_cst_p (const value_range *vr) |
| { |
| return (vr->kind () == VR_RANGE && range_has_numeric_bounds_p (vr)); |
| } |
| |
| /* Return the single symbol (an SSA_NAME) contained in T if any, or NULL_TREE |
| otherwise. We only handle additive operations and set NEG to true if the |
| symbol is negated and INV to the invariant part, if any. */ |
| |
| tree |
| get_single_symbol (tree t, bool *neg, tree *inv) |
| { |
| bool neg_; |
| tree inv_; |
| |
| *inv = NULL_TREE; |
| *neg = false; |
| |
| if (TREE_CODE (t) == PLUS_EXPR |
| || TREE_CODE (t) == POINTER_PLUS_EXPR |
| || TREE_CODE (t) == MINUS_EXPR) |
| { |
| if (is_gimple_min_invariant (TREE_OPERAND (t, 0))) |
| { |
| neg_ = (TREE_CODE (t) == MINUS_EXPR); |
| inv_ = TREE_OPERAND (t, 0); |
| t = TREE_OPERAND (t, 1); |
| } |
| else if (is_gimple_min_invariant (TREE_OPERAND (t, 1))) |
| { |
| neg_ = false; |
| inv_ = TREE_OPERAND (t, 1); |
| t = TREE_OPERAND (t, 0); |
| } |
| else |
| return NULL_TREE; |
| } |
| else |
| { |
| neg_ = false; |
| inv_ = NULL_TREE; |
| } |
| |
| if (TREE_CODE (t) == NEGATE_EXPR) |
| { |
| t = TREE_OPERAND (t, 0); |
| neg_ = !neg_; |
| } |
| |
| if (TREE_CODE (t) != SSA_NAME) |
| return NULL_TREE; |
| |
| if (inv_ && TREE_OVERFLOW_P (inv_)) |
| inv_ = drop_tree_overflow (inv_); |
| |
| *neg = neg_; |
| *inv = inv_; |
| return t; |
| } |
| |
| /* The reverse operation: build a symbolic expression with TYPE |
| from symbol SYM, negated according to NEG, and invariant INV. */ |
| |
| static tree |
| build_symbolic_expr (tree type, tree sym, bool neg, tree inv) |
| { |
| const bool pointer_p = POINTER_TYPE_P (type); |
| tree t = sym; |
| |
| if (neg) |
| t = build1 (NEGATE_EXPR, type, t); |
| |
| if (integer_zerop (inv)) |
| return t; |
| |
| return build2 (pointer_p ? POINTER_PLUS_EXPR : PLUS_EXPR, type, t, inv); |
| } |
| |
| /* Return |
| 1 if VAL < VAL2 |
| 0 if !(VAL < VAL2) |
| -2 if those are incomparable. */ |
| int |
| operand_less_p (tree val, tree val2) |
| { |
| /* LT is folded faster than GE and others. Inline the common case. */ |
| if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST) |
| return tree_int_cst_lt (val, val2); |
| else if (TREE_CODE (val) == SSA_NAME && TREE_CODE (val2) == SSA_NAME) |
| return val == val2 ? 0 : -2; |
| else |
| { |
| int cmp = compare_values (val, val2); |
| if (cmp == -1) |
| return 1; |
| else if (cmp == 0 || cmp == 1) |
| return 0; |
| else |
| return -2; |
| } |
| |
| return 0; |
| } |
| |
| /* Compare two values VAL1 and VAL2. Return |
| |
| -2 if VAL1 and VAL2 cannot be compared at compile-time, |
| -1 if VAL1 < VAL2, |
| 0 if VAL1 == VAL2, |
| +1 if VAL1 > VAL2, and |
| +2 if VAL1 != VAL2 |
| |
| This is similar to tree_int_cst_compare but supports pointer values |
| and values that cannot be compared at compile time. |
| |
| If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to |
| true if the return value is only valid if we assume that signed |
| overflow is undefined. */ |
| |
| int |
| compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p) |
| { |
| if (val1 == val2) |
| return 0; |
| |
| /* Below we rely on the fact that VAL1 and VAL2 are both pointers or |
| both integers. */ |
| gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1)) |
| == POINTER_TYPE_P (TREE_TYPE (val2))); |
| |
| /* Convert the two values into the same type. This is needed because |
| sizetype causes sign extension even for unsigned types. */ |
| if (!useless_type_conversion_p (TREE_TYPE (val1), TREE_TYPE (val2))) |
| val2 = fold_convert (TREE_TYPE (val1), val2); |
| |
| const bool overflow_undefined |
| = INTEGRAL_TYPE_P (TREE_TYPE (val1)) |
| && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)); |
| tree inv1, inv2; |
| bool neg1, neg2; |
| tree sym1 = get_single_symbol (val1, &neg1, &inv1); |
| tree sym2 = get_single_symbol (val2, &neg2, &inv2); |
| |
| /* If VAL1 and VAL2 are of the form '[-]NAME [+ CST]', return -1 or +1 |
| accordingly. If VAL1 and VAL2 don't use the same name, return -2. */ |
| if (sym1 && sym2) |
| { |
| /* Both values must use the same name with the same sign. */ |
| if (sym1 != sym2 || neg1 != neg2) |
| return -2; |
| |
| /* [-]NAME + CST == [-]NAME + CST. */ |
| if (inv1 == inv2) |
| return 0; |
| |
| /* If overflow is defined we cannot simplify more. */ |
| if (!overflow_undefined) |
| return -2; |
| |
| if (strict_overflow_p != NULL |
| /* Symbolic range building sets the no-warning bit to declare |
| that overflow doesn't happen. */ |
| && (!inv1 || !warning_suppressed_p (val1, OPT_Woverflow)) |
| && (!inv2 || !warning_suppressed_p (val2, OPT_Woverflow))) |
| *strict_overflow_p = true; |
| |
| if (!inv1) |
| inv1 = build_int_cst (TREE_TYPE (val1), 0); |
| if (!inv2) |
| inv2 = build_int_cst (TREE_TYPE (val2), 0); |
| |
| return wi::cmp (wi::to_wide (inv1), wi::to_wide (inv2), |
| TYPE_SIGN (TREE_TYPE (val1))); |
| } |
| |
| const bool cst1 = is_gimple_min_invariant (val1); |
| const bool cst2 = is_gimple_min_invariant (val2); |
| |
| /* If one is of the form '[-]NAME + CST' and the other is constant, then |
| it might be possible to say something depending on the constants. */ |
| if ((sym1 && inv1 && cst2) || (sym2 && inv2 && cst1)) |
| { |
| if (!overflow_undefined) |
| return -2; |
| |
| if (strict_overflow_p != NULL |
| /* Symbolic range building sets the no-warning bit to declare |
| that overflow doesn't happen. */ |
| && (!sym1 || !warning_suppressed_p (val1, OPT_Woverflow)) |
| && (!sym2 || !warning_suppressed_p (val2, OPT_Woverflow))) |
| *strict_overflow_p = true; |
| |
| const signop sgn = TYPE_SIGN (TREE_TYPE (val1)); |
| tree cst = cst1 ? val1 : val2; |
| tree inv = cst1 ? inv2 : inv1; |
| |
| /* Compute the difference between the constants. If it overflows or |
| underflows, this means that we can trivially compare the NAME with |
| it and, consequently, the two values with each other. */ |
| wide_int diff = wi::to_wide (cst) - wi::to_wide (inv); |
| if (wi::cmp (0, wi::to_wide (inv), sgn) |
| != wi::cmp (diff, wi::to_wide (cst), sgn)) |
| { |
| const int res = wi::cmp (wi::to_wide (cst), wi::to_wide (inv), sgn); |
| return cst1 ? res : -res; |
| } |
| |
| return -2; |
| } |
| |
| /* We cannot say anything more for non-constants. */ |
| if (!cst1 || !cst2) |
| return -2; |
| |
| if (!POINTER_TYPE_P (TREE_TYPE (val1))) |
| { |
| /* We cannot compare overflowed values. */ |
| if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2)) |
| return -2; |
| |
| if (TREE_CODE (val1) == INTEGER_CST |
| && TREE_CODE (val2) == INTEGER_CST) |
| return tree_int_cst_compare (val1, val2); |
| |
| if (poly_int_tree_p (val1) && poly_int_tree_p (val2)) |
| { |
| if (known_eq (wi::to_poly_widest (val1), |
| wi::to_poly_widest (val2))) |
| return 0; |
| if (known_lt (wi::to_poly_widest (val1), |
| wi::to_poly_widest (val2))) |
| return -1; |
| if (known_gt (wi::to_poly_widest (val1), |
| wi::to_poly_widest (val2))) |
| return 1; |
| } |
| |
| return -2; |
| } |
| else |
| { |
| if (TREE_CODE (val1) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST) |
| { |
| /* We cannot compare overflowed values. */ |
| if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2)) |
| return -2; |
| |
| return tree_int_cst_compare (val1, val2); |
| } |
| |
| /* First see if VAL1 and VAL2 are not the same. */ |
| if (operand_equal_p (val1, val2, 0)) |
| return 0; |
| |
| fold_defer_overflow_warnings (); |
| |
| /* If VAL1 is a lower address than VAL2, return -1. */ |
| tree t = fold_binary_to_constant (LT_EXPR, boolean_type_node, val1, val2); |
| if (t && integer_onep (t)) |
| { |
| fold_undefer_and_ignore_overflow_warnings (); |
| return -1; |
| } |
| |
| /* If VAL1 is a higher address than VAL2, return +1. */ |
| t = fold_binary_to_constant (LT_EXPR, boolean_type_node, val2, val1); |
| if (t && integer_onep (t)) |
| { |
| fold_undefer_and_ignore_overflow_warnings (); |
| return 1; |
| } |
| |
| /* If VAL1 is different than VAL2, return +2. */ |
| t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2); |
| fold_undefer_and_ignore_overflow_warnings (); |
| if (t && integer_onep (t)) |
| return 2; |
| |
| return -2; |
| } |
| } |
| |
| /* Compare values like compare_values_warnv. */ |
| |
| int |
| compare_values (tree val1, tree val2) |
| { |
| bool sop; |
| return compare_values_warnv (val1, val2, &sop); |
| } |
| |
| /* If BOUND will include a symbolic bound, adjust it accordingly, |
| otherwise leave it as is. |
| |
| CODE is the original operation that combined the bounds (PLUS_EXPR |
| or MINUS_EXPR). |
| |
| TYPE is the type of the original operation. |
| |
| SYM_OPn is the symbolic for OPn if it has a symbolic. |
| |
| NEG_OPn is TRUE if the OPn was negated. */ |
| |
| static void |
| adjust_symbolic_bound (tree &bound, enum tree_code code, tree type, |
| tree sym_op0, tree sym_op1, |
| bool neg_op0, bool neg_op1) |
| { |
| bool minus_p = (code == MINUS_EXPR); |
| /* If the result bound is constant, we're done; otherwise, build the |
| symbolic lower bound. */ |
| if (sym_op0 == sym_op1) |
| ; |
| else if (sym_op0) |
| bound = build_symbolic_expr (type, sym_op0, |
| neg_op0, bound); |
| else if (sym_op1) |
| { |
| /* We may not negate if that might introduce |
| undefined overflow. */ |
| if (!minus_p |
| || neg_op1 |
| || TYPE_OVERFLOW_WRAPS (type)) |
| bound = build_symbolic_expr (type, sym_op1, |
| neg_op1 ^ minus_p, bound); |
| else |
| bound = NULL_TREE; |
| } |
| } |
| |
| /* Combine OP1 and OP1, which are two parts of a bound, into one wide |
| int bound according to CODE. CODE is the operation combining the |
| bound (either a PLUS_EXPR or a MINUS_EXPR). |
| |
| TYPE is the type of the combine operation. |
| |
| WI is the wide int to store the result. |
| |
| OVF is -1 if an underflow occurred, +1 if an overflow occurred or 0 |
| if over/underflow occurred. */ |
| |
| static void |
| combine_bound (enum tree_code code, wide_int &wi, wi::overflow_type &ovf, |
| tree type, tree op0, tree op1) |
| { |
| bool minus_p = (code == MINUS_EXPR); |
| const signop sgn = TYPE_SIGN (type); |
| const unsigned int prec = TYPE_PRECISION (type); |
| |
| /* Combine the bounds, if any. */ |
| if (op0 && op1) |
| { |
| if (minus_p) |
| wi = wi::sub (wi::to_wide (op0), wi::to_wide (op1), sgn, &ovf); |
| else |
| wi = wi::add (wi::to_wide (op0), wi::to_wide (op1), sgn, &ovf); |
| } |
| else if (op0) |
| wi = wi::to_wide (op0); |
| else if (op1) |
| { |
| if (minus_p) |
| wi = wi::neg (wi::to_wide (op1), &ovf); |
| else |
| wi = wi::to_wide (op1); |
| } |
| else |
| wi = wi::shwi (0, prec); |
| } |
| |
| /* Given a range in [WMIN, WMAX], adjust it for possible overflow and |
| put the result in VR. |
| |
| TYPE is the type of the range. |
| |
| MIN_OVF and MAX_OVF indicate what type of overflow, if any, |
| occurred while originally calculating WMIN or WMAX. -1 indicates |
| underflow. +1 indicates overflow. 0 indicates neither. */ |
| |
| static void |
| set_value_range_with_overflow (value_range_kind &kind, tree &min, tree &max, |
| tree type, |
| const wide_int &wmin, const wide_int &wmax, |
| wi::overflow_type min_ovf, |
| wi::overflow_type max_ovf) |
| { |
| const signop sgn = TYPE_SIGN (type); |
| const unsigned int prec = TYPE_PRECISION (type); |
| |
| /* For one bit precision if max < min, then the swapped |
| range covers all values. */ |
| if (prec == 1 && wi::lt_p (wmax, wmin, sgn)) |
| { |
| kind = VR_VARYING; |
| return; |
| } |
| |
| if (TYPE_OVERFLOW_WRAPS (type)) |
| { |
| /* If overflow wraps, truncate the values and adjust the |
| range kind and bounds appropriately. */ |
| wide_int tmin = wide_int::from (wmin, prec, sgn); |
| wide_int tmax = wide_int::from (wmax, prec, sgn); |
| if ((min_ovf != wi::OVF_NONE) == (max_ovf != wi::OVF_NONE)) |
| { |
| /* If the limits are swapped, we wrapped around and cover |
| the entire range. */ |
| if (wi::gt_p (tmin, tmax, sgn)) |
| kind = VR_VARYING; |
| else |
| { |
| kind = VR_RANGE; |
| /* No overflow or both overflow or underflow. The |
| range kind stays VR_RANGE. */ |
| min = wide_int_to_tree (type, tmin); |
| max = wide_int_to_tree (type, tmax); |
| } |
| return; |
| } |
| else if ((min_ovf == wi::OVF_UNDERFLOW && max_ovf == wi::OVF_NONE) |
| || (max_ovf == wi::OVF_OVERFLOW && min_ovf == wi::OVF_NONE)) |
| { |
| /* Min underflow or max overflow. The range kind |
| changes to VR_ANTI_RANGE. */ |
| bool covers = false; |
| wide_int tem = tmin; |
| tmin = tmax + 1; |
| if (wi::cmp (tmin, tmax, sgn) < 0) |
| covers = true; |
| tmax = tem - 1; |
| if (wi::cmp (tmax, tem, sgn) > 0) |
| covers = true; |
| /* If the anti-range would cover nothing, drop to varying. |
| Likewise if the anti-range bounds are outside of the |
| types values. */ |
| if (covers || wi::cmp (tmin, tmax, sgn) > 0) |
| { |
| kind = VR_VARYING; |
| return; |
| } |
| kind = VR_ANTI_RANGE; |
| min = wide_int_to_tree (type, tmin); |
| max = wide_int_to_tree (type, tmax); |
| return; |
| } |
| else |
| { |
| /* Other underflow and/or overflow, drop to VR_VARYING. */ |
| kind = VR_VARYING; |
| return; |
| } |
| } |
| else |
| { |
| /* If overflow does not wrap, saturate to the types min/max |
| value. */ |
| wide_int type_min = wi::min_value (prec, sgn); |
| wide_int type_max = wi::max_value (prec, sgn); |
| kind = VR_RANGE; |
| if (min_ovf == wi::OVF_UNDERFLOW) |
| min = wide_int_to_tree (type, type_min); |
| else if (min_ovf == wi::OVF_OVERFLOW) |
| min = wide_int_to_tree (type, type_max); |
| else |
| min = wide_int_to_tree (type, wmin); |
| |
| if (max_ovf == wi::OVF_UNDERFLOW) |
| max = wide_int_to_tree (type, type_min); |
| else if (max_ovf == wi::OVF_OVERFLOW) |
| max = wide_int_to_tree (type, type_max); |
| else |
| max = wide_int_to_tree (type, wmax); |
| } |
| } |
| |
| /* Fold two value range's of a POINTER_PLUS_EXPR into VR. */ |
| |
| static void |
| extract_range_from_pointer_plus_expr (value_range *vr, |
| enum tree_code code, |
| tree expr_type, |
| const value_range *vr0, |
| const value_range *vr1) |
| { |
| gcc_checking_assert (POINTER_TYPE_P (expr_type) |
| && code == POINTER_PLUS_EXPR); |
| /* For pointer types, we are really only interested in asserting |
| whether the expression evaluates to non-NULL. |
| With -fno-delete-null-pointer-checks we need to be more |
| conservative. As some object might reside at address 0, |
| then some offset could be added to it and the same offset |
| subtracted again and the result would be NULL. |
| E.g. |
| static int a[12]; where &a[0] is NULL and |
| ptr = &a[6]; |
| ptr -= 6; |
| ptr will be NULL here, even when there is POINTER_PLUS_EXPR |
| where the first range doesn't include zero and the second one |
| doesn't either. As the second operand is sizetype (unsigned), |
| consider all ranges where the MSB could be set as possible |
| subtractions where the result might be NULL. */ |
| if ((!range_includes_zero_p (vr0) |
| || !range_includes_zero_p (vr1)) |
| && !TYPE_OVERFLOW_WRAPS (expr_type) |
| && (flag_delete_null_pointer_checks |
| || (range_int_cst_p (vr1) |
| && !tree_int_cst_sign_bit (vr1->max ())))) |
| vr->set_nonzero (expr_type); |
| else if (vr0->zero_p () && vr1->zero_p ()) |
| vr->set_zero (expr_type); |
| else |
| vr->set_varying (expr_type); |
| } |
| |
| /* Extract range information from a PLUS/MINUS_EXPR and store the |
| result in *VR. */ |
| |
| static void |
| extract_range_from_plus_minus_expr (value_range *vr, |
| enum tree_code code, |
| tree expr_type, |
| const value_range *vr0_, |
| const value_range *vr1_) |
| { |
| gcc_checking_assert (code == PLUS_EXPR || code == MINUS_EXPR); |
| |
| value_range vr0 = *vr0_, vr1 = *vr1_; |
| value_range vrtem0, vrtem1; |
| |
| /* Now canonicalize anti-ranges to ranges when they are not symbolic |
| and express ~[] op X as ([]' op X) U ([]'' op X). */ |
| if (vr0.kind () == VR_ANTI_RANGE |
| && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1)) |
| { |
| extract_range_from_plus_minus_expr (vr, code, expr_type, &vrtem0, vr1_); |
| if (!vrtem1.undefined_p ()) |
| { |
| value_range vrres; |
| extract_range_from_plus_minus_expr (&vrres, code, expr_type, |
| &vrtem1, vr1_); |
| vr->union_ (&vrres); |
| } |
| return; |
| } |
| /* Likewise for X op ~[]. */ |
| if (vr1.kind () == VR_ANTI_RANGE |
| && ranges_from_anti_range (&vr1, &vrtem0, &vrtem1)) |
| { |
| extract_range_from_plus_minus_expr (vr, code, expr_type, vr0_, &vrtem0); |
| if (!vrtem1.undefined_p ()) |
| { |
| value_range vrres; |
| extract_range_from_plus_minus_expr (&vrres, code, expr_type, |
| vr0_, &vrtem1); |
| vr->union_ (&vrres); |
| } |
| return; |
| } |
| |
| value_range_kind kind; |
| value_range_kind vr0_kind = vr0.kind (), vr1_kind = vr1.kind (); |
| tree vr0_min = vr0.min (), vr0_max = vr0.max (); |
| tree vr1_min = vr1.min (), vr1_max = vr1.max (); |
| tree min = NULL_TREE, max = NULL_TREE; |
| |
| /* This will normalize things such that calculating |
| [0,0] - VR_VARYING is not dropped to varying, but is |
| calculated as [MIN+1, MAX]. */ |
| if (vr0.varying_p ()) |
| { |
| vr0_kind = VR_RANGE; |
| vr0_min = vrp_val_min (expr_type); |
| vr0_max = vrp_val_max (expr_type); |
| } |
| if (vr1.varying_p ()) |
| { |
| vr1_kind = VR_RANGE; |
| vr1_min = vrp_val_min (expr_type); |
| vr1_max = vrp_val_max (expr_type); |
| } |
| |
| const bool minus_p = (code == MINUS_EXPR); |
| tree min_op0 = vr0_min; |
| tree min_op1 = minus_p ? vr1_max : vr1_min; |
| tree max_op0 = vr0_max; |
| tree max_op1 = minus_p ? vr1_min : vr1_max; |
| tree sym_min_op0 = NULL_TREE; |
| tree sym_min_op1 = NULL_TREE; |
| tree sym_max_op0 = NULL_TREE; |
| tree sym_max_op1 = NULL_TREE; |
| bool neg_min_op0, neg_min_op1, neg_max_op0, neg_max_op1; |
| |
| neg_min_op0 = neg_min_op1 = neg_max_op0 = neg_max_op1 = false; |
| |
| /* If we have a PLUS or MINUS with two VR_RANGEs, either constant or |
| single-symbolic ranges, try to compute the precise resulting range, |
| but only if we know that this resulting range will also be constant |
| or single-symbolic. */ |
| if (vr0_kind == VR_RANGE && vr1_kind == VR_RANGE |
| && (TREE_CODE (min_op0) == INTEGER_CST |
| || (sym_min_op0 |
| = get_single_symbol (min_op0, &neg_min_op0, &min_op0))) |
| && (TREE_CODE (min_op1) == INTEGER_CST |
| || (sym_min_op1 |
| = get_single_symbol (min_op1, &neg_min_op1, &min_op1))) |
| && (!(sym_min_op0 && sym_min_op1) |
| || (sym_min_op0 == sym_min_op1 |
| && neg_min_op0 == (minus_p ? neg_min_op1 : !neg_min_op1))) |
| && (TREE_CODE (max_op0) == INTEGER_CST |
| || (sym_max_op0 |
| = get_single_symbol (max_op0, &neg_max_op0, &max_op0))) |
| && (TREE_CODE (max_op1) == INTEGER_CST |
| || (sym_max_op1 |
| = get_single_symbol (max_op1, &neg_max_op1, &max_op1))) |
| && (!(sym_max_op0 && sym_max_op1) |
| || (sym_max_op0 == sym_max_op1 |
| && neg_max_op0 == (minus_p ? neg_max_op1 : !neg_max_op1)))) |
| { |
| wide_int wmin, wmax; |
| wi::overflow_type min_ovf = wi::OVF_NONE; |
| wi::overflow_type max_ovf = wi::OVF_NONE; |
| |
| /* Build the bounds. */ |
| combine_bound (code, wmin, min_ovf, expr_type, min_op0, min_op1); |
| combine_bound (code, wmax, max_ovf, expr_type, max_op0, max_op1); |
| |
| /* If the resulting range will be symbolic, we need to eliminate any |
| explicit or implicit overflow introduced in the above computation |
| because compare_values could make an incorrect use of it. That's |
| why we require one of the ranges to be a singleton. */ |
| if ((sym_min_op0 != sym_min_op1 || sym_max_op0 != sym_max_op1) |
| && ((bool)min_ovf || (bool)max_ovf |
| || (min_op0 != max_op0 && min_op1 != max_op1))) |
| { |
| vr->set_varying (expr_type); |
| return; |
| } |
| |
| /* Adjust the range for possible overflow. */ |
| set_value_range_with_overflow (kind, min, max, expr_type, |
| wmin, wmax, min_ovf, max_ovf); |
| if (kind == VR_VARYING) |
| { |
| vr->set_varying (expr_type); |
| return; |
| } |
| |
| /* Build the symbolic bounds if needed. */ |
| adjust_symbolic_bound (min, code, expr_type, |
| sym_min_op0, sym_min_op1, |
| neg_min_op0, neg_min_op1); |
| adjust_symbolic_bound (max, code, expr_type, |
| sym_max_op0, sym_max_op1, |
| neg_max_op0, neg_max_op1); |
| } |
| else |
| { |
| /* For other cases, for example if we have a PLUS_EXPR with two |
| VR_ANTI_RANGEs, drop to VR_VARYING. It would take more effort |
| to compute a precise range for such a case. |
| ??? General even mixed range kind operations can be expressed |
| by for example transforming ~[3, 5] + [1, 2] to range-only |
| operations and a union primitive: |
| [-INF, 2] + [1, 2] U [5, +INF] + [1, 2] |
| [-INF+1, 4] U [6, +INF(OVF)] |
| though usually the union is not exactly representable with |
| a single range or anti-range as the above is |
| [-INF+1, +INF(OVF)] intersected with ~[5, 5] |
| but one could use a scheme similar to equivalences for this. */ |
| vr->set_varying (expr_type); |
| return; |
| } |
| |
| /* If either MIN or MAX overflowed, then set the resulting range to |
| VARYING. */ |
| if (min == NULL_TREE |
| || TREE_OVERFLOW_P (min) |
| || max == NULL_TREE |
| || TREE_OVERFLOW_P (max)) |
| { |
| vr->set_varying (expr_type); |
| return; |
| } |
| |
| int cmp = compare_values (min, max); |
| if (cmp == -2 || cmp == 1) |
| { |
| /* If the new range has its limits swapped around (MIN > MAX), |
| then the operation caused one of them to wrap around, mark |
| the new range VARYING. */ |
| vr->set_varying (expr_type); |
| } |
| else |
| vr->set (min, max, kind); |
| } |
| |
| /* Return the range-ops handler for CODE and EXPR_TYPE. If no |
| suitable operator is found, return NULL and set VR to VARYING. */ |
| |
| static const range_operator * |
| get_range_op_handler (value_range *vr, |
| enum tree_code code, |
| tree expr_type) |
| { |
| const range_operator *op = range_op_handler (code, expr_type); |
| if (!op) |
| vr->set_varying (expr_type); |
| return op; |
| } |
| |
| /* If the types passed are supported, return TRUE, otherwise set VR to |
| VARYING and return FALSE. */ |
| |
| static bool |
| supported_types_p (value_range *vr, |
| tree type0, |
| tree type1 = NULL) |
| { |
| if (!value_range::supports_type_p (type0) |
| || (type1 && !value_range::supports_type_p (type1))) |
| { |
| vr->set_varying (type0); |
| return false; |
| } |
| return true; |
| } |
| |
| /* If any of the ranges passed are defined, return TRUE, otherwise set |
| VR to UNDEFINED and return FALSE. */ |
| |
| static bool |
| defined_ranges_p (value_range *vr, |
| const value_range *vr0, const value_range *vr1 = NULL) |
| { |
| if (vr0->undefined_p () && (!vr1 || vr1->undefined_p ())) |
| { |
| vr->set_undefined (); |
| return false; |
| } |
| return true; |
| } |
| |
| static value_range |
| drop_undefines_to_varying (const value_range *vr, tree expr_type) |
| { |
| if (vr->undefined_p ()) |
| return value_range (expr_type); |
| else |
| return *vr; |
| } |
| |
| /* If any operand is symbolic, perform a binary operation on them and |
| return TRUE, otherwise return FALSE. */ |
| |
| static bool |
| range_fold_binary_symbolics_p (value_range *vr, |
| tree_code code, |
| tree expr_type, |
| const value_range *vr0_, |
| const value_range *vr1_) |
| { |
| if (vr0_->symbolic_p () || vr1_->symbolic_p ()) |
| { |
| value_range vr0 = drop_undefines_to_varying (vr0_, expr_type); |
| value_range vr1 = drop_undefines_to_varying (vr1_, expr_type); |
| if ((code == PLUS_EXPR || code == MINUS_EXPR)) |
| { |
| extract_range_from_plus_minus_expr (vr, code, expr_type, |
| &vr0, &vr1); |
| return true; |
| } |
| if (POINTER_TYPE_P (expr_type) && code == POINTER_PLUS_EXPR) |
| { |
| extract_range_from_pointer_plus_expr (vr, code, expr_type, |
| &vr0, &vr1); |
| return true; |
| } |
| const range_operator *op = get_range_op_handler (vr, code, expr_type); |
| vr0.normalize_symbolics (); |
| vr1.normalize_symbolics (); |
| return op->fold_range (*vr, expr_type, vr0, vr1); |
| } |
| return false; |
| } |
| |
| /* If operand is symbolic, perform a unary operation on it and return |
| TRUE, otherwise return FALSE. */ |
| |
| static bool |
| range_fold_unary_symbolics_p (value_range *vr, |
| tree_code code, |
| tree expr_type, |
| const value_range *vr0) |
| { |
| if (vr0->symbolic_p ()) |
| { |
| if (code == NEGATE_EXPR) |
| { |
| /* -X is simply 0 - X. */ |
| value_range zero; |
| zero.set_zero (vr0->type ()); |
| range_fold_binary_expr (vr, MINUS_EXPR, expr_type, &zero, vr0); |
| return true; |
| } |
| if (code == BIT_NOT_EXPR) |
| { |
| /* ~X is simply -1 - X. */ |
| value_range minusone; |
| minusone.set (build_int_cst (vr0->type (), -1)); |
| range_fold_binary_expr (vr, MINUS_EXPR, expr_type, &minusone, vr0); |
| return true; |
| } |
| const range_operator *op = get_range_op_handler (vr, code, expr_type); |
| value_range vr0_cst (*vr0); |
| vr0_cst.normalize_symbolics (); |
| return op->fold_range (*vr, expr_type, vr0_cst, value_range (expr_type)); |
| } |
| return false; |
| } |
| |
| /* Perform a binary operation on a pair of ranges. */ |
| |
| void |
| range_fold_binary_expr (value_range *vr, |
| enum tree_code code, |
| tree expr_type, |
| const value_range *vr0_, |
| const value_range *vr1_) |
| { |
| if (!supported_types_p (vr, expr_type) |
| || !defined_ranges_p (vr, vr0_, vr1_)) |
| return; |
| const range_operator *op = get_range_op_handler (vr, code, expr_type); |
| if (!op) |
| return; |
| |
| if (range_fold_binary_symbolics_p (vr, code, expr_type, vr0_, vr1_)) |
| return; |
| |
| value_range vr0 (*vr0_); |
| value_range vr1 (*vr1_); |
| if (vr0.undefined_p ()) |
| vr0.set_varying (expr_type); |
| if (vr1.undefined_p ()) |
| vr1.set_varying (expr_type); |
| vr0.normalize_addresses (); |
| vr1.normalize_addresses (); |
| op->fold_range (*vr, expr_type, vr0, vr1); |
| } |
| |
| /* Perform a unary operation on a range. */ |
| |
| void |
| range_fold_unary_expr (value_range *vr, |
| enum tree_code code, tree expr_type, |
| const value_range *vr0, |
| tree vr0_type) |
| { |
| if (!supported_types_p (vr, expr_type, vr0_type) |
| || !defined_ranges_p (vr, vr0)) |
| return; |
| const range_operator *op = get_range_op_handler (vr, code, expr_type); |
| if (!op) |
| return; |
| |
| if (range_fold_unary_symbolics_p (vr, code, expr_type, vr0)) |
| return; |
| |
| value_range vr0_cst (*vr0); |
| vr0_cst.normalize_addresses (); |
| op->fold_range (*vr, expr_type, vr0_cst, value_range (expr_type)); |
| } |
| |
| /* If the range of values taken by OP can be inferred after STMT executes, |
| return the comparison code (COMP_CODE_P) and value (VAL_P) that |
| describes the inferred range. Return true if a range could be |
| inferred. */ |
| |
| bool |
| infer_value_range (gimple *stmt, tree op, tree_code *comp_code_p, tree *val_p) |
| { |
| *val_p = NULL_TREE; |
| *comp_code_p = ERROR_MARK; |
| |
| /* Do not attempt to infer anything in names that flow through |
| abnormal edges. */ |
| if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op)) |
| return false; |
| |
| /* If STMT is the last statement of a basic block with no normal |
| successors, there is no point inferring anything about any of its |
| operands. We would not be able to find a proper insertion point |
| for the assertion, anyway. */ |
| if (stmt_ends_bb_p (stmt)) |
| { |
| edge_iterator ei; |
| edge e; |
| |
| FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs) |
| if (!(e->flags & (EDGE_ABNORMAL|EDGE_EH))) |
| break; |
| if (e == NULL) |
| return false; |
| } |
| |
| if (infer_nonnull_range (stmt, op)) |
| { |
| *val_p = build_int_cst (TREE_TYPE (op), 0); |
| *comp_code_p = NE_EXPR; |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* Dump assert_info structure. */ |
| |
| void |
| dump_assert_info (FILE *file, const assert_info &assert) |
| { |
| fprintf (file, "Assert for: "); |
| print_generic_expr (file, assert.name); |
| fprintf (file, "\n\tPREDICATE: expr=["); |
| print_generic_expr (file, assert.expr); |
| fprintf (file, "] %s ", get_tree_code_name (assert.comp_code)); |
| fprintf (file, "val=["); |
| print_generic_expr (file, assert.val); |
| fprintf (file, "]\n\n"); |
| } |
| |
| DEBUG_FUNCTION void |
| debug (const assert_info &assert) |
| { |
| dump_assert_info (stderr, assert); |
| } |
| |
| /* Dump a vector of assert_info's. */ |
| |
| void |
| dump_asserts_info (FILE *file, const vec<assert_info> &asserts) |
| { |
| for (unsigned i = 0; i < asserts.length (); ++i) |
| { |
| dump_assert_info (file, asserts[i]); |
| fprintf (file, "\n"); |
| } |
| } |
| |
| DEBUG_FUNCTION void |
| debug (const vec<assert_info> &asserts) |
| { |
| dump_asserts_info (stderr, asserts); |
| } |
| |
| /* Push the assert info for NAME, EXPR, COMP_CODE and VAL to ASSERTS. */ |
| |
| static void |
| add_assert_info (vec<assert_info> &asserts, |
| tree name, tree expr, enum tree_code comp_code, tree val) |
| { |
| assert_info info; |
| info.comp_code = comp_code; |
| info.name = name; |
| if (TREE_OVERFLOW_P (val)) |
| val = drop_tree_overflow (val); |
| info.val = val; |
| info.expr = expr; |
| asserts.safe_push (info); |
| if (dump_enabled_p ()) |
| dump_printf (MSG_NOTE | MSG_PRIORITY_INTERNALS, |
| "Adding assert for %T from %T %s %T\n", |
| name, expr, op_symbol_code (comp_code), val); |
| } |
| |
| /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME. |
| Extract a suitable test code and value and store them into *CODE_P and |
| *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P. |
| |
| If no extraction was possible, return FALSE, otherwise return TRUE. |
| |
| If INVERT is true, then we invert the result stored into *CODE_P. */ |
| |
| static bool |
| extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code, |
| tree cond_op0, tree cond_op1, |
| bool invert, enum tree_code *code_p, |
| tree *val_p) |
| { |
| enum tree_code comp_code; |
| tree val; |
| |
| /* Otherwise, we have a comparison of the form NAME COMP VAL |
| or VAL COMP NAME. */ |
| if (name == cond_op1) |
| { |
| /* If the predicate is of the form VAL COMP NAME, flip |
| COMP around because we need to register NAME as the |
| first operand in the predicate. */ |
| comp_code = swap_tree_comparison (cond_code); |
| val = cond_op0; |
| } |
| else if (name == cond_op0) |
| { |
| /* The comparison is of the form NAME COMP VAL, so the |
| comparison code remains unchanged. */ |
| comp_code = cond_code; |
| val = cond_op1; |
| } |
| else |
| gcc_unreachable (); |
| |
| /* Invert the comparison code as necessary. */ |
| if (invert) |
| comp_code = invert_tree_comparison (comp_code, 0); |
| |
| /* VRP only handles integral and pointer types. */ |
| if (! INTEGRAL_TYPE_P (TREE_TYPE (val)) |
| && ! POINTER_TYPE_P (TREE_TYPE (val))) |
| return false; |
| |
| /* Do not register always-false predicates. |
| FIXME: this works around a limitation in fold() when dealing with |
| enumerations. Given 'enum { N1, N2 } x;', fold will not |
| fold 'if (x > N2)' to 'if (0)'. */ |
| if ((comp_code == GT_EXPR || comp_code == LT_EXPR) |
| && INTEGRAL_TYPE_P (TREE_TYPE (val))) |
| { |
| tree min = TYPE_MIN_VALUE (TREE_TYPE (val)); |
| tree max = TYPE_MAX_VALUE (TREE_TYPE (val)); |
| |
| if (comp_code == GT_EXPR |
| && (!max |
| || compare_values (val, max) == 0)) |
| return false; |
| |
| if (comp_code == LT_EXPR |
| && (!min |
| || compare_values (val, min) == 0)) |
| return false; |
| } |
| *code_p = comp_code; |
| *val_p = val; |
| return true; |
| } |
| |
| /* Find out smallest RES where RES > VAL && (RES & MASK) == RES, if any |
| (otherwise return VAL). VAL and MASK must be zero-extended for |
| precision PREC. If SGNBIT is non-zero, first xor VAL with SGNBIT |
| (to transform signed values into unsigned) and at the end xor |
| SGNBIT back. */ |
| |
| wide_int |
| masked_increment (const wide_int &val_in, const wide_int &mask, |
| const wide_int &sgnbit, unsigned int prec) |
| { |
| wide_int bit = wi::one (prec), res; |
| unsigned int i; |
| |
| wide_int val = val_in ^ sgnbit; |
| for (i = 0; i < prec; i++, bit += bit) |
| { |
| res = mask; |
| if ((res & bit) == 0) |
| continue; |
| res = bit - 1; |
| res = wi::bit_and_not (val + bit, res); |
| res &= mask; |
| if (wi::gtu_p (res, val)) |
| return res ^ sgnbit; |
| } |
| return val ^ sgnbit; |
| } |
| |
| /* Helper for overflow_comparison_p |
| |
| OP0 CODE OP1 is a comparison. Examine the comparison and potentially |
| OP1's defining statement to see if it ultimately has the form |
| OP0 CODE (OP0 PLUS INTEGER_CST) |
| |
| If so, return TRUE indicating this is an overflow test and store into |
| *NEW_CST an updated constant that can be used in a narrowed range test. |
| |
| REVERSED indicates if the comparison was originally: |
| |
| OP1 CODE' OP0. |
| |
| This affects how we build the updated constant. */ |
| |
| static bool |
| overflow_comparison_p_1 (enum tree_code code, tree op0, tree op1, |
| bool follow_assert_exprs, bool reversed, tree *new_cst) |
| { |
| /* See if this is a relational operation between two SSA_NAMES with |
| unsigned, overflow wrapping values. If so, check it more deeply. */ |
| if ((code == LT_EXPR || code == LE_EXPR |
| || code == GE_EXPR || code == GT_EXPR) |
| && TREE_CODE (op0) == SSA_NAME |
| && TREE_CODE (op1) == SSA_NAME |
| && INTEGRAL_TYPE_P (TREE_TYPE (op0)) |
| && TYPE_UNSIGNED (TREE_TYPE (op0)) |
| && TYPE_OVERFLOW_WRAPS (TREE_TYPE (op0))) |
| { |
| gimple *op1_def = SSA_NAME_DEF_STMT (op1); |
| |
| /* If requested, follow any ASSERT_EXPRs backwards for OP1. */ |
| if (follow_assert_exprs) |
| { |
| while (gimple_assign_single_p (op1_def) |
| && TREE_CODE (gimple_assign_rhs1 (op1_def)) == ASSERT_EXPR) |
| { |
| op1 = TREE_OPERAND (gimple_assign_rhs1 (op1_def), 0); |
| if (TREE_CODE (op1) != SSA_NAME) |
| break; |
| op1_def = SSA_NAME_DEF_STMT (op1); |
| } |
| } |
| |
| /* Now look at the defining statement of OP1 to see if it adds |
| or subtracts a nonzero constant from another operand. */ |
| if (op1_def |
| && is_gimple_assign (op1_def) |
| && gimple_assign_rhs_code (op1_def) == PLUS_EXPR |
| && TREE_CODE (gimple_assign_rhs2 (op1_def)) == INTEGER_CST |
| && !integer_zerop (gimple_assign_rhs2 (op1_def))) |
| { |
| tree target = gimple_assign_rhs1 (op1_def); |
| |
| /* If requested, follow ASSERT_EXPRs backwards for op0 looking |
| for one where TARGET appears on the RHS. */ |
| if (follow_assert_exprs) |
| { |
| /* Now see if that "other operand" is op0, following the chain |
| of ASSERT_EXPRs if necessary. */ |
| gimple *op0_def = SSA_NAME_DEF_STMT (op0); |
| while (op0 != target |
| && gimple_assign_single_p (op0_def) |
| && TREE_CODE (gimple_assign_rhs1 (op0_def)) == ASSERT_EXPR) |
| { |
| op0 = TREE_OPERAND (gimple_assign_rhs1 (op0_def), 0); |
| if (TREE_CODE (op0) != SSA_NAME) |
| break; |
| op0_def = SSA_NAME_DEF_STMT (op0); |
| } |
| } |
| |
| /* If we did not find our target SSA_NAME, then this is not |
| an overflow test. */ |
| if (op0 != target) |
| return false; |
| |
| tree type = TREE_TYPE (op0); |
| wide_int max = wi::max_value (TYPE_PRECISION (type), UNSIGNED); |
| tree inc = gimple_assign_rhs2 (op1_def); |
| if (reversed) |
| *new_cst = wide_int_to_tree (type, max + wi::to_wide (inc)); |
| else |
| *new_cst = wide_int_to_tree (type, max - wi::to_wide (inc)); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /* OP0 CODE OP1 is a comparison. Examine the comparison and potentially |
| OP1's defining statement to see if it ultimately has the form |
| OP0 CODE (OP0 PLUS INTEGER_CST) |
| |
| If so, return TRUE indicating this is an overflow test and store into |
| *NEW_CST an updated constant that can be used in a narrowed range test. |
| |
| These statements are left as-is in the IL to facilitate discovery of |
| {ADD,SUB}_OVERFLOW sequences later in the optimizer pipeline. But |
| the alternate range representation is often useful within VRP. */ |
| |
| bool |
| overflow_comparison_p (tree_code code, tree name, tree val, |
| bool use_equiv_p, tree *new_cst) |
| { |
| if (overflow_comparison_p_1 (code, name, val, use_equiv_p, false, new_cst)) |
| return true; |
| return overflow_comparison_p_1 (swap_tree_comparison (code), val, name, |
| use_equiv_p, true, new_cst); |
| } |
| |
| |
| /* Try to register an edge assertion for SSA name NAME on edge E for |
| the condition COND contributing to the conditional jump pointed to by BSI. |
| Invert the condition COND if INVERT is true. */ |
| |
| static void |
| register_edge_assert_for_2 (tree name, edge e, |
| enum tree_code cond_code, |
| tree cond_op0, tree cond_op1, bool invert, |
| vec<assert_info> &asserts) |
| { |
| tree val; |
| enum tree_code comp_code; |
| |
| if (!extract_code_and_val_from_cond_with_ops (name, cond_code, |
| cond_op0, |
| cond_op1, |
| invert, &comp_code, &val)) |
| return; |
| |
| /* Queue the assert. */ |
| tree x; |
| if (overflow_comparison_p (comp_code, name, val, false, &x)) |
| { |
| enum tree_code new_code = ((comp_code == GT_EXPR || comp_code == GE_EXPR) |
| ? GT_EXPR : LE_EXPR); |
| add_assert_info (asserts, name, name, new_code, x); |
| } |
| add_assert_info (asserts, name, name, comp_code, val); |
| |
| /* In the case of NAME <= CST and NAME being defined as |
| NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2 |
| and NAME2 <= CST - CST2. We can do the same for NAME > CST. |
| This catches range and anti-range tests. */ |
| if ((comp_code == LE_EXPR |
| || comp_code == GT_EXPR) |
| && TREE_CODE (val) == INTEGER_CST |
| && TYPE_UNSIGNED (TREE_TYPE (val))) |
| { |
| gimple *def_stmt = SSA_NAME_DEF_STMT (name); |
| tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE; |
| |
| /* Extract CST2 from the (optional) addition. */ |
| if (is_gimple_assign (def_stmt) |
| && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR) |
| { |
| name2 = gimple_assign_rhs1 (def_stmt); |
| cst2 = gimple_assign_rhs2 (def_stmt); |
| if (TREE_CODE (name2) == SSA_NAME |
| && TREE_CODE (cst2) == INTEGER_CST) |
| def_stmt = SSA_NAME_DEF_STMT (name2); |
| } |
| |
| /* Extract NAME2 from the (optional) sign-changing cast. */ |
| if (gassign *ass = dyn_cast <gassign *> (def_stmt)) |
| { |
| if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (ass)) |
| && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (ass))) |
| && (TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (ass))) |
| == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (ass))))) |
| name3 = gimple_assign_rhs1 (ass); |
| } |
| |
| /* If name3 is used later, create an ASSERT_EXPR for it. */ |
| if (name3 != NULL_TREE |
| && TREE_CODE (name3) == SSA_NAME |
| && (cst2 == NULL_TREE |
| || TREE_CODE (cst2) == INTEGER_CST) |
| && INTEGRAL_TYPE_P (TREE_TYPE (name3))) |
| { |
| tree tmp; |
| |
| /* Build an expression for the range test. */ |
| tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3); |
| if (cst2 != NULL_TREE) |
| tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2); |
| add_assert_info (asserts, name3, tmp, comp_code, val); |
| } |
| |
| /* If name2 is used later, create an ASSERT_EXPR for it. */ |
| if (name2 != NULL_TREE |
| && TREE_CODE (name2) == SSA_NAME |
| && TREE_CODE (cst2) == INTEGER_CST |
| && INTEGRAL_TYPE_P (TREE_TYPE (name2))) |
| { |
| tree tmp; |
| |
| /* Build an expression for the range test. */ |
| tmp = name2; |
| if (TREE_TYPE (name) != TREE_TYPE (name2)) |
| tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp); |
| if (cst2 != NULL_TREE) |
| tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2); |
| add_assert_info (asserts, name2, tmp, comp_code, val); |
| } |
| } |
| |
| /* In the case of post-in/decrement tests like if (i++) ... and uses |
| of the in/decremented value on the edge the extra name we want to |
| assert for is not on the def chain of the name compared. Instead |
| it is in the set of use stmts. |
| Similar cases happen for conversions that were simplified through |
| fold_{sign_changed,widened}_comparison. */ |
| if ((comp_code == NE_EXPR |
| || comp_code == EQ_EXPR) |
| && TREE_CODE (val) == INTEGER_CST) |
| { |
| imm_use_iterator ui; |
| gimple *use_stmt; |
| FOR_EACH_IMM_USE_STMT (use_stmt, ui, name) |
| { |
| if (!is_gimple_assign (use_stmt)) |
| continue; |
| |
| /* Cut off to use-stmts that are dominating the predecessor. */ |
| if (!dominated_by_p (CDI_DOMINATORS, e->src, gimple_bb (use_stmt))) |
| continue; |
| |
| tree name2 = gimple_assign_lhs (use_stmt); |
| if (TREE_CODE (name2) != SSA_NAME) |
| continue; |
| |
| enum tree_code code = gimple_assign_rhs_code (use_stmt); |
| tree cst; |
| if (code == PLUS_EXPR |
| || code == MINUS_EXPR) |
| { |
| cst = gimple_assign_rhs2 (use_stmt); |
| if (TREE_CODE (cst) != INTEGER_CST) |
| continue; |
| cst = int_const_binop (code, val, cst); |
| } |
| else if (CONVERT_EXPR_CODE_P (code)) |
| { |
| /* For truncating conversions we cannot record |
| an inequality. */ |
| if (comp_code == NE_EXPR |
| && (TYPE_PRECISION (TREE_TYPE (name2)) |
| < TYPE_PRECISION (TREE_TYPE (name)))) |
| continue; |
| cst = fold_convert (TREE_TYPE (name2), val); |
| } |
| else |
| continue; |
| |
| if (TREE_OVERFLOW_P (cst)) |
| cst = drop_tree_overflow (cst); |
| add_assert_info (asserts, name2, name2, comp_code, cst); |
| } |
| } |
| |
| if (TREE_CODE_CLASS (comp_code) == tcc_comparison |
| && TREE_CODE (val) == INTEGER_CST) |
| { |
| gimple *def_stmt = SSA_NAME_DEF_STMT (name); |
| tree name2 = NULL_TREE, names[2], cst2 = NULL_TREE; |
| tree val2 = NULL_TREE; |
| unsigned int prec = TYPE_PRECISION (TREE_TYPE (val)); |
| wide_int mask = wi::zero (prec); |
| unsigned int nprec = prec; |
| enum tree_code rhs_code = ERROR_MARK; |
| |
| if (is_gimple_assign (def_stmt)) |
| rhs_code = gimple_assign_rhs_code (def_stmt); |
| |
| /* In the case of NAME != CST1 where NAME = A +- CST2 we can |
| assert that A != CST1 -+ CST2. */ |
| if ((comp_code == EQ_EXPR || comp_code == NE_EXPR) |
| && (rhs_code == PLUS_EXPR || rhs_code == MINUS_EXPR)) |
| { |
| tree op0 = gimple_assign_rhs1 (def_stmt); |
| tree op1 = gimple_assign_rhs2 (def_stmt); |
| if (TREE_CODE (op0) == SSA_NAME |
| && TREE_CODE (op1) == INTEGER_CST) |
| { |
| enum tree_code reverse_op = (rhs_code == PLUS_EXPR |
| ? MINUS_EXPR : PLUS_EXPR); |
| op1 = int_const_binop (reverse_op, val, op1); |
| if (TREE_OVERFLOW (op1)) |
| op1 = drop_tree_overflow (op1); |
| add_assert_info (asserts, op0, op0, comp_code, op1); |
| } |
| } |
| |
| /* Add asserts for NAME cmp CST and NAME being defined |
| as NAME = (int) NAME2. */ |
| if (!TYPE_UNSIGNED (TREE_TYPE (val)) |
| && (comp_code == LE_EXPR || comp_code == LT_EXPR |
| || comp_code == GT_EXPR || comp_code == GE_EXPR) |
| && gimple_assign_cast_p (def_stmt)) |
| { |
| name2 = gimple_assign_rhs1 (def_stmt); |
| if (CONVERT_EXPR_CODE_P (rhs_code) |
| && TREE_CODE (name2) == SSA_NAME |
| && INTEGRAL_TYPE_P (TREE_TYPE (name2)) |
| && TYPE_UNSIGNED (TREE_TYPE (name2)) |
| && prec == TYPE_PRECISION (TREE_TYPE (name2)) |
| && (comp_code == LE_EXPR || comp_code == GT_EXPR |
| || !tree_int_cst_equal (val, |
| TYPE_MIN_VALUE (TREE_TYPE (val))))) |
| { |
| tree tmp, cst; |
| enum tree_code new_comp_code = comp_code; |
| |
| cst = fold_convert (TREE_TYPE (name2), |
| TYPE_MIN_VALUE (TREE_TYPE (val))); |
| /* Build an expression for the range test. */ |
| tmp = build2 (PLUS_EXPR, TREE_TYPE (name2), name2, cst); |
| cst = fold_build2 (PLUS_EXPR, TREE_TYPE (name2), cst, |
| fold_convert (TREE_TYPE (name2), val)); |
| if (comp_code == LT_EXPR || comp_code == GE_EXPR) |
| { |
| new_comp_code = comp_code == LT_EXPR ? LE_EXPR : GT_EXPR; |
| cst = fold_build2 (MINUS_EXPR, TREE_TYPE (name2), cst, |
| build_int_cst (TREE_TYPE (name2), 1)); |
| } |
| add_assert_info (asserts, name2, tmp, new_comp_code, cst); |
| } |
| } |
| |
| /* Add asserts for NAME cmp CST and NAME being defined as |
| NAME = NAME2 >> CST2. |
| |
| Extract CST2 from the right shift. */ |
| if (rhs_code == RSHIFT_EXPR) |
| { |
| name2 = gimple_assign_rhs1 (def_stmt); |
| cst2 = gimple_assign_rhs2 (def_stmt); |
| if (TREE_CODE (name2) == SSA_NAME |
| && tree_fits_uhwi_p (cst2) |
| && INTEGRAL_TYPE_P (TREE_TYPE (name2)) |
| && IN_RANGE (tree_to_uhwi (cst2), 1, prec - 1) |
| && type_has_mode_precision_p (TREE_TYPE (val))) |
| { |
| mask = wi::mask (tree_to_uhwi (cst2), false, prec); |
| val2 = fold_binary (LSHIFT_EXPR, TREE_TYPE (val), val, cst2); |
| } |
| } |
| if (val2 != NULL_TREE |
| && TREE_CODE (val2) == INTEGER_CST |
| && simple_cst_equal (fold_build2 (RSHIFT_EXPR, |
| TREE_TYPE (val), |
| val2, cst2), val)) |
| { |
| enum tree_code new_comp_code = comp_code; |
| tree tmp, new_val; |
| |
| tmp = name2; |
| if (comp_code == EQ_EXPR || comp_code == NE_EXPR) |
| { |
| if (!TYPE_UNSIGNED (TREE_TYPE (val))) |
| { |
| tree type = build_nonstandard_integer_type (prec, 1); |
| tmp = build1 (NOP_EXPR, type, name2); |
| val2 = fold_convert (type, val2); |
| } |
| tmp = fold_build2 (MINUS_EXPR, TREE_TYPE (tmp), tmp, val2); |
| new_val = wide_int_to_tree (TREE_TYPE (tmp), mask); |
| new_comp_code = comp_code == EQ_EXPR ? LE_EXPR : GT_EXPR; |
| } |
| else if (comp_code == LT_EXPR || comp_code == GE_EXPR) |
| { |
| wide_int minval |
| = wi::min_value (prec, TYPE_SIGN (TREE_TYPE (val))); |
| new_val = val2; |
| if (minval == wi::to_wide (new_val)) |
| new_val = NULL_TREE; |
| } |
| else |
| { |
| wide_int maxval |
| = wi::max_value (prec, TYPE_SIGN (TREE_TYPE (val))); |
| mask |= wi::to_wide (val2); |
| if (wi::eq_p (mask, maxval)) |
| new_val = NULL_TREE; |
| else |
| new_val = wide_int_to_tree (TREE_TYPE (val2), mask); |
| } |
| |
| if (new_val) |
| add_assert_info (asserts, name2, tmp, new_comp_code, new_val); |
| } |
| |
| /* If we have a conversion that doesn't change the value of the source |
| simply register the same assert for it. */ |
| if (CONVERT_EXPR_CODE_P (rhs_code)) |
| { |
| value_range vr; |
| tree rhs1 = gimple_assign_rhs1 (def_stmt); |
| if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) |
| && TREE_CODE (rhs1) == SSA_NAME |
| /* Make sure the relation preserves the upper/lower boundary of |
| the range conservatively. */ |
| && (comp_code == NE_EXPR |
| || comp_code == EQ_EXPR |
| || (TYPE_SIGN (TREE_TYPE (name)) |
| == TYPE_SIGN (TREE_TYPE (rhs1))) |
| || ((comp_code == LE_EXPR |
| || comp_code == LT_EXPR) |
| && !TYPE_UNSIGNED (TREE_TYPE (rhs1))) |
| || ((comp_code == GE_EXPR |
| || comp_code == GT_EXPR) |
| && TYPE_UNSIGNED (TREE_TYPE (rhs1)))) |
| /* And the conversion does not alter the value we compare |
| against and all values in rhs1 can be represented in |
| the converted to type. */ |
| && int_fits_type_p (val, TREE_TYPE (rhs1)) |
| && ((TYPE_PRECISION (TREE_TYPE (name)) |
| > TYPE_PRECISION (TREE_TYPE (rhs1))) |
| || ((get_range_query (cfun)->range_of_expr (vr, rhs1) |
| && vr.kind () == VR_RANGE) |
| && wi::fits_to_tree_p |
| (widest_int::from (vr.lower_bound (), |
| TYPE_SIGN (TREE_TYPE (rhs1))), |
| TREE_TYPE (name)) |
| && wi::fits_to_tree_p |
| (widest_int::from (vr.upper_bound (), |
| TYPE_SIGN (TREE_TYPE (rhs1))), |
| TREE_TYPE (name))))) |
| add_assert_info (asserts, rhs1, rhs1, |
| comp_code, fold_convert (TREE_TYPE (rhs1), val)); |
| } |
| |
| /* Add asserts for NAME cmp CST and NAME being defined as |
| NAME = NAME2 & CST2. |
| |
| Extract CST2 from the and. |
| |
| Also handle |
| NAME = (unsigned) NAME2; |
| casts where NAME's type is unsigned and has smaller precision |
| than NAME2's type as if it was NAME = NAME2 & MASK. */ |
| names[0] = NULL_TREE; |
| names[1] = NULL_TREE; |
| cst2 = NULL_TREE; |
| if (rhs_code == BIT_AND_EXPR |
| || (CONVERT_EXPR_CODE_P (rhs_code) |
| && INTEGRAL_TYPE_P (TREE_TYPE (val)) |
| && TYPE_UNSIGNED (TREE_TYPE (val)) |
| && TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt))) |
| > prec)) |
| { |
| name2 = gimple_assign_rhs1 (def_stmt); |
| if (rhs_code == BIT_AND_EXPR) |
| cst2 = gimple_assign_rhs2 (def_stmt); |
| else |
| { |
| cst2 = TYPE_MAX_VALUE (TREE_TYPE (val)); |
| nprec = TYPE_PRECISION (TREE_TYPE (name2)); |
| } |
| if (TREE_CODE (name2) == SSA_NAME |
| && INTEGRAL_TYPE_P (TREE_TYPE (name2)) |
| && TREE_CODE (cst2) == INTEGER_CST |
| && !integer_zerop (cst2) |
| && (nprec > 1 |
| || TYPE_UNSIGNED (TREE_TYPE (val)))) |
| { |
| gimple *def_stmt2 = SSA_NAME_DEF_STMT (name2); |
| if (gimple_assign_cast_p (def_stmt2)) |
| { |
| names[1] = gimple_assign_rhs1 (def_stmt2); |
| if (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt2)) |
| || TREE_CODE (names[1]) != SSA_NAME |
| || !INTEGRAL_TYPE_P (TREE_TYPE (names[1])) |
| || (TYPE_PRECISION (TREE_TYPE (name2)) |
| != TYPE_PRECISION (TREE_TYPE (names[1])))) |
| names[1] = NULL_TREE; |
| } |
| names[0] = name2; |
| } |
| } |
| if (names[0] || names[1]) |
| { |
| wide_int minv, maxv, valv, cst2v; |
| wide_int tem, sgnbit; |
| bool valid_p = false, valn, cst2n; |
| enum tree_code ccode = comp_code; |
| |
| valv = wide_int::from (wi::to_wide (val), nprec, UNSIGNED); |
| cst2v = wide_int::from (wi::to_wide (cst2), nprec, UNSIGNED); |
| valn = wi::neg_p (valv, TYPE_SIGN (TREE_TYPE (val))); |
| cst2n = wi::neg_p (cst2v, TYPE_SIGN (TREE_TYPE (val))); |
| /* If CST2 doesn't have most significant bit set, |
| but VAL is negative, we have comparison like |
| if ((x & 0x123) > -4) (always true). Just give up. */ |
| if (!cst2n && valn) |
| ccode = ERROR_MARK; |
| if (cst2n) |
| sgnbit = wi::set_bit_in_zero (nprec - 1, nprec); |
| else |
| sgnbit = wi::zero (nprec); |
| minv = valv & cst2v; |
| switch (ccode) |
| { |
| case EQ_EXPR: |
| /* Minimum unsigned value for equality is VAL & CST2 |
| (should be equal to VAL, otherwise we probably should |
| have folded the comparison into false) and |
| maximum unsigned value is VAL | ~CST2. */ |
| maxv = valv | ~cst2v; |
| valid_p = true; |
| break; |
| |
| case NE_EXPR: |
| tem = valv | ~cst2v; |
| /* If VAL is 0, handle (X & CST2) != 0 as (X & CST2) > 0U. */ |
| if (valv == 0) |
| { |
| cst2n = false; |
| sgnbit = wi::zero (nprec); |
| goto gt_expr; |
| } |
| /* If (VAL | ~CST2) is all ones, handle it as |
| (X & CST2) < VAL. */ |
| if (tem == -1) |
| { |
| cst2n = false; |
| valn = false; |
| sgnbit = wi::zero (nprec); |
| goto lt_expr; |
| } |
| if (!cst2n && wi::neg_p (cst2v)) |
| sgnbit = wi::set_bit_in_zero (nprec - 1, nprec); |
| if (sgnbit != 0) |
| { |
| if (valv == sgnbit) |
| { |
| cst2n = true; |
| valn = true; |
| goto gt_expr; |
| } |
| if (tem == wi::mask (nprec - 1, false, nprec)) |
| { |
| cst2n = true; |
| goto lt_expr; |
| } |
| if (!cst2n) |
| sgnbit = wi::zero (nprec); |
| } |
| break; |
| |
| case GE_EXPR: |
| /* Minimum unsigned value for >= if (VAL & CST2) == VAL |
| is VAL and maximum unsigned value is ~0. For signed |
| comparison, if CST2 doesn't have most significant bit |
| set, handle it similarly. If CST2 has MSB set, |
| the minimum is the same, and maximum is ~0U/2. */ |
| if (minv != valv) |
| { |
| /* If (VAL & CST2) != VAL, X & CST2 can't be equal to |
| VAL. */ |
| minv = masked_increment (valv, cst2v, sgnbit, nprec); |
| if (minv == valv) |
| break; |
| } |
| maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec); |
| valid_p = true; |
| break; |
| |
| case GT_EXPR: |
| gt_expr: |
| /* Find out smallest MINV where MINV > VAL |
| && (MINV & CST2) == MINV, if any. If VAL is signed and |
| CST2 has MSB set, compute it biased by 1 << (nprec - 1). */ |
| minv = masked_increment (valv, cst2v, sgnbit, nprec); |
| if (minv == valv) |
| break; |
| maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec); |
| valid_p = true; |
| break; |
| |
| case LE_EXPR: |
| /* Minimum unsigned value for <= is 0 and maximum |
| unsigned value is VAL | ~CST2 if (VAL & CST2) == VAL. |
| Otherwise, find smallest VAL2 where VAL2 > VAL |
| && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2 |
| as maximum. |
| For signed comparison, if CST2 doesn't have most |
| significant bit set, handle it similarly. If CST2 has |
| MSB set, the maximum is the same and minimum is INT_MIN. */ |
| if (minv == valv) |
| maxv = valv; |
| else |
| { |
| maxv = masked_increment (valv, cst2v, sgnbit, nprec); |
| if (maxv == valv) |
| break; |
| maxv -= 1; |
| } |
| maxv |= ~cst2v; |
| minv = sgnbit; |
| valid_p = true; |
| break; |
| |
| case LT_EXPR: |
| lt_expr: |
| /* Minimum unsigned value for < is 0 and maximum |
| unsigned value is (VAL-1) | ~CST2 if (VAL & CST2) == VAL. |
| Otherwise, find smallest VAL2 where VAL2 > VAL |
| && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2 |
| as maximum. |
| For signed comparison, if CST2 doesn't have most |
| significant bit set, handle it similarly. If CST2 has |
| MSB set, the maximum is the same and minimum is INT_MIN. */ |
| if (minv == valv) |
| { |
| if (valv == sgnbit) |
| break; |
| maxv = valv; |
| } |
| else |
| { |
| maxv = masked_increment (valv, cst2v, sgnbit, nprec); |
| if (maxv == valv) |
| break; |
| } |
| maxv -= 1; |
| maxv |= ~cst2v; |
| minv = sgnbit; |
| valid_p = true; |
| break; |
| |
| default: |
| break; |
| } |
| if (valid_p |
| && (maxv - minv) != -1) |
| { |
| tree tmp, new_val, type; |
| int i; |
| |
| for (i = 0; i < 2; i++) |
| if (names[i]) |
| { |
| wide_int maxv2 = maxv; |
| tmp = names[i]; |
| type = TREE_TYPE (names[i]); |
| if (!TYPE_UNSIGNED (type)) |
| { |
| type = build_nonstandard_integer_type (nprec, 1); |
| tmp = build1 (NOP_EXPR, type, names[i]); |
| } |
| if (minv != 0) |
| { |
| tmp = build2 (PLUS_EXPR, type, tmp, |
| wide_int_to_tree (type, -minv)); |
| maxv2 = maxv - minv; |
| } |
| new_val = wide_int_to_tree (type, maxv2); |
| add_assert_info (asserts, names[i], tmp, LE_EXPR, new_val); |
| } |
| } |
| } |
| } |
| } |
| |
| /* OP is an operand of a truth value expression which is known to have |
| a particular value. Register any asserts for OP and for any |
| operands in OP's defining statement. |
| |
| If CODE is EQ_EXPR, then we want to register OP is zero (false), |
| if CODE is NE_EXPR, then we want to register OP is nonzero (true). */ |
| |
| static void |
| register_edge_assert_for_1 (tree op, enum tree_code code, |
| edge e, vec<assert_info> &asserts) |
| { |
| gimple *op_def; |
| tree val; |
| enum tree_code rhs_code; |
| |
| /* We only care about SSA_NAMEs. */ |
| if (TREE_CODE (op) != SSA_NAME) |
| return; |
| |
| /* We know that OP will have a zero or nonzero value. */ |
| val = build_int_cst (TREE_TYPE (op), 0); |
| add_assert_info (asserts, op, op, code, val); |
| |
| /* Now look at how OP is set. If it's set from a comparison, |
| a truth operation or some bit operations, then we may be able |
| to register information about the operands of that assignment. */ |
| op_def = SSA_NAME_DEF_STMT (op); |
| if (gimple_code (op_def) != GIMPLE_ASSIGN) |
| return; |
| |
| rhs_code = gimple_assign_rhs_code (op_def); |
| |
| if (TREE_CODE_CLASS (rhs_code) == tcc_comparison) |
| { |
| bool invert = (code == EQ_EXPR ? true : false); |
| tree op0 = gimple_assign_rhs1 (op_def); |
| tree op1 = gimple_assign_rhs2 (op_def); |
| |
| if (TREE_CODE (op0) == SSA_NAME) |
| register_edge_assert_for_2 (op0, e, rhs_code, op0, op1, invert, asserts); |
| if (TREE_CODE (op1) == SSA_NAME) |
| register_edge_assert_for_2 (op1, e, rhs_code, op0, op1, invert, asserts); |
| } |
| else if ((code == NE_EXPR |
| && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR) |
| || (code == EQ_EXPR |
| && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)) |
| { |
| /* Recurse on each operand. */ |
| tree op0 = gimple_assign_rhs1 (op_def); |
| tree op1 = gimple_assign_rhs2 (op_def); |
| if (TREE_CODE (op0) == SSA_NAME |
| && has_single_use (op0)) |
| register_edge_assert_for_1 (op0, code, e, asserts); |
| if (TREE_CODE (op1) == SSA_NAME |
| && has_single_use (op1)) |
| register_edge_assert_for_1 (op1, code, e, asserts); |
| } |
| else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR |
| && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1) |
| { |
| /* Recurse, flipping CODE. */ |
| code = invert_tree_comparison (code, false); |
| register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), code, e, asserts); |
| } |
| else if (gimple_assign_rhs_code (op_def) == SSA_NAME) |
| { |
| /* Recurse through the copy. */ |
| register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), code, e, asserts); |
| } |
| else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def))) |
| { |
| /* Recurse through the type conversion, unless it is a narrowing |
| conversion or conversion from non-integral type. */ |
| tree rhs = gimple_assign_rhs1 (op_def); |
| if (INTEGRAL_TYPE_P (TREE_TYPE (rhs)) |
| && (TYPE_PRECISION (TREE_TYPE (rhs)) |
| <= TYPE_PRECISION (TREE_TYPE (op)))) |
| register_edge_assert_for_1 (rhs, code, e, asserts); |
| } |
| } |
| |
| /* Check if comparison |
| NAME COND_OP INTEGER_CST |
| has a form of |
| (X & 11...100..0) COND_OP XX...X00...0 |
| Such comparison can yield assertions like |
| X >= XX...X00...0 |
| X <= XX...X11...1 |
| in case of COND_OP being EQ_EXPR or |
| X < XX...X00...0 |
| X > XX...X11...1 |
| in case of NE_EXPR. */ |
| |
| static bool |
| is_masked_range_test (tree name, tree valt, enum tree_code cond_code, |
| tree *new_name, tree *low, enum tree_code *low_code, |
| tree *high, enum tree_code *high_code) |
| { |
| gimple *def_stmt = SSA_NAME_DEF_STMT (name); |
| |
| if (!is_gimple_assign (def_stmt) |
| || gimple_assign_rhs_code (def_stmt) != BIT_AND_EXPR) |
| return false; |
| |
| tree t = gimple_assign_rhs1 (def_stmt); |
| tree maskt = gimple_assign_rhs2 (def_stmt); |
| if (TREE_CODE (t) != SSA_NAME || TREE_CODE (maskt) != INTEGER_CST) |
| return false; |
| |
| wi::tree_to_wide_ref mask = wi::to_wide (maskt); |
| wide_int inv_mask = ~mask; |
| /* Must have been removed by now so don't bother optimizing. */ |
| if (mask == 0 || inv_mask == 0) |
| return false; |
| |
| /* Assume VALT is INTEGER_CST. */ |
| wi::tree_to_wide_ref val = wi::to_wide (valt); |
| |
| if ((inv_mask & (inv_mask + 1)) != 0 |
| || (val & mask) != val) |
| return false; |
| |
| bool is_range = cond_code == EQ_EXPR; |
| |
| tree type = TREE_TYPE (t); |
| wide_int min = wi::min_value (type), |
| max = wi::max_value (type); |
| |
| if (is_range) |
| { |
| *low_code = val == min ? ERROR_MARK : GE_EXPR; |
| *high_code = val == max ? ERROR_MARK : LE_EXPR; |
| } |
| else |
| { |
| /* We can still generate assertion if one of alternatives |
| is known to always be false. */ |
| if (val == min) |
| { |
| *low_code = (enum tree_code) 0; |
| *high_code = GT_EXPR; |
| } |
| else if ((val | inv_mask) == max) |
| { |
| *low_code = LT_EXPR; |
| *high_code = (enum tree_code) 0; |
| } |
| else |
| return false; |
| } |
| |
| *new_name = t; |
| *low = wide_int_to_tree (type, val); |
| *high = wide_int_to_tree (type, val | inv_mask); |
| |
| return true; |
| } |
| |
| /* Try to register an edge assertion for SSA name NAME on edge E for |
| the condition COND contributing to the conditional jump pointed to by |
| SI. */ |
| |
| void |
| register_edge_assert_for (tree name, edge e, |
| enum tree_code cond_code, tree cond_op0, |
| tree cond_op1, vec<assert_info> &asserts) |
| { |
| tree val; |
| enum tree_code comp_code; |
| bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0; |
| |
| /* Do not attempt to infer anything in names that flow through |
| abnormal edges. */ |
| if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name)) |
| return; |
| |
| if (!extract_code_and_val_from_cond_with_ops (name, cond_code, |
| cond_op0, cond_op1, |
| is_else_edge, |
| &comp_code, &val)) |
| return; |
| |
| /* Register ASSERT_EXPRs for name. */ |
| register_edge_assert_for_2 (name, e, cond_code, cond_op0, |
| cond_op1, is_else_edge, asserts); |
| |
| |
| /* If COND is effectively an equality test of an SSA_NAME against |
| the value zero or one, then we may be able to assert values |
| for SSA_NAMEs which flow into COND. */ |
| |
| /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining |
| statement of NAME we can assert both operands of the BIT_AND_EXPR |
| have nonzero value. */ |
| if ((comp_code == EQ_EXPR && integer_onep (val)) |
| || (comp_code == NE_EXPR && integer_zerop (val))) |
| { |
| gimple *def_stmt = SSA_NAME_DEF_STMT (name); |
| |
| if (is_gimple_assign (def_stmt) |
| && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR) |
| { |
| tree op0 = gimple_assign_rhs1 (def_stmt); |
| tree op1 = gimple_assign_rhs2 (def_stmt); |
| register_edge_assert_for_1 (op0, NE_EXPR, e, asserts); |
| register_edge_assert_for_1 (op1, NE_EXPR, e, asserts); |
| } |
| else if (is_gimple_assign (def_stmt) |
| && (TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt)) |
| == tcc_comparison)) |
| register_edge_assert_for_1 (name, NE_EXPR, e, asserts); |
| } |
| |
| /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining |
| statement of NAME we can assert both operands of the BIT_IOR_EXPR |
| have zero value. */ |
| if ((comp_code == EQ_EXPR && integer_zerop (val)) |
| || (comp_code == NE_EXPR |
| && integer_onep (val) |
| && TYPE_PRECISION (TREE_TYPE (name)) == 1)) |
| { |
| gimple *def_stmt = SSA_NAME_DEF_STMT (name); |
| |
| /* For BIT_IOR_EXPR only if NAME == 0 both operands have |
| necessarily zero value, or if type-precision is one. */ |
| if (is_gimple_assign (def_stmt) |
| && gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR) |
| { |
| tree op0 = gimple_assign_rhs1 (def_stmt); |
| tree op1 = gimple_assign_rhs2 (def_stmt); |
| register_edge_assert_for_1 (op0, EQ_EXPR, e, asserts); |
| register_edge_assert_for_1 (op1, EQ_EXPR, e, asserts); |
| } |
| else if (is_gimple_assign (def_stmt) |
| && (TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt)) |
| == tcc_comparison)) |
| register_edge_assert_for_1 (name, EQ_EXPR, e, asserts); |
| } |
| |
| /* Sometimes we can infer ranges from (NAME & MASK) == VALUE. */ |
| if ((comp_code == EQ_EXPR || comp_code == NE_EXPR) |
| && TREE_CODE (val) == INTEGER_CST) |
| { |
| enum tree_code low_code, high_code; |
| tree low, high; |
| if (is_masked_range_test (name, val, comp_code, &name, &low, |
| &low_code, &high, &high_code)) |
| { |
| if (low_code != ERROR_MARK) |
| register_edge_assert_for_2 (name, e, low_code, name, |
| low, /*invert*/false, asserts); |
| if (high_code != ERROR_MARK) |
| register_edge_assert_for_2 (name, e, high_code, name, |
| high, /*invert*/false, asserts); |
| } |
| } |
| } |
| |
| /* Handle |
| _4 = x_3 & 31; |
| if (_4 != 0) |
| goto <bb 6>; |
| else |
| goto <bb 7>; |
| <bb 6>: |
| __builtin_unreachable (); |
| <bb 7>: |
| x_5 = ASSERT_EXPR <x_3, ...>; |
| If x_3 has no other immediate uses (checked by caller), |
| var is the x_3 var from ASSERT_EXPR, we can clear low 5 bits |
| from the non-zero bitmask. */ |
| |
| void |
| maybe_set_nonzero_bits (edge e, tree var) |
| { |
| basic_block cond_bb = e->src; |
| gimple *stmt = last_stmt (cond_bb); |
| tree cst; |
| |
| if (stmt == NULL |
| || gimple_code (stmt) != GIMPLE_COND |
| || gimple_cond_code (stmt) != ((e->flags & EDGE_TRUE_VALUE) |
| ? EQ_EXPR : NE_EXPR) |
| || TREE_CODE (gimple_cond_lhs (stmt)) != SSA_NAME |
| || !integer_zerop (gimple_cond_rhs (stmt))) |
| return; |
| |
| stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (stmt)); |
| if (!is_gimple_assign (stmt) |
| || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR |
| || TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST) |
| return; |
| if (gimple_assign_rhs1 (stmt) != var) |
| { |
| gimple *stmt2; |
| |
| if (TREE_CODE (gimple_assign_rhs1 (stmt)) != SSA_NAME) |
| return; |
| stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); |
| if (!gimple_assign_cast_p (stmt2) |
| || gimple_assign_rhs1 (stmt2) != var |
| || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt2)) |
| || (TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt))) |
| != TYPE_PRECISION (TREE_TYPE (var)))) |
| return; |
| } |
| cst = gimple_assign_rhs2 (stmt); |
| set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var), |
| wi::to_wide (cst))); |
| } |
| |
| /* Return true if STMT is interesting for VRP. */ |
| |
| bool |
| stmt_interesting_for_vrp (gimple *stmt) |
| { |
| if (gimple_code (stmt) == GIMPLE_PHI) |
| { |
| tree res = gimple_phi_result (stmt); |
| return (!virtual_operand_p (res) |
| && (INTEGRAL_TYPE_P (TREE_TYPE (res)) |
| || POINTER_TYPE_P (TREE_TYPE (res)))); |
| } |
| else if (is_gimple_assign (stmt) || is_gimple_call (stmt)) |
| { |
| tree lhs = gimple_get_lhs (stmt); |
| |
| /* In general, assignments with virtual operands are not useful |
| for deriving ranges, with the obvious exception of calls to |
| builtin functions. */ |
| if (lhs && TREE_CODE (lhs) == SSA_NAME |
| && (INTEGRAL_TYPE_P (TREE_TYPE (lhs)) |
| || POINTER_TYPE_P (TREE_TYPE (lhs))) |
| && (is_gimple_call (stmt) |
| || !gimple_vuse (stmt))) |
| return true; |
| else if (is_gimple_call (stmt) && gimple_call_internal_p (stmt)) |
| switch (gimple_call_internal_fn (stmt)) |
| { |
| case IFN_ADD_OVERFLOW: |
| case IFN_SUB_OVERFLOW: |
| case IFN_MUL_OVERFLOW: |
| case IFN_ATOMIC_COMPARE_EXCHANGE: |
| /* These internal calls return _Complex integer type, |
| but are interesting to VRP nevertheless. */ |
| if (lhs && TREE_CODE (lhs) == SSA_NAME) |
| return true; |
| break; |
| default: |
| break; |
| } |
| } |
| else if (gimple_code (stmt) == GIMPLE_COND |
| || gimple_code (stmt) == GIMPLE_SWITCH) |
| return true; |
| |
| return false; |
| } |
| |
| /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL |
| that includes the value VAL. The search is restricted to the range |
| [START_IDX, n - 1] where n is the size of VEC. |
| |
| If there is a CASE_LABEL for VAL, its index is placed in IDX and true is |
| returned. |
| |
| If there is no CASE_LABEL for VAL and there is one that is larger than VAL, |
| it is placed in IDX and false is returned. |
| |
| If VAL is larger than any CASE_LABEL, n is placed on IDX and false is |
| returned. */ |
| |
| bool |
| find_case_label_index (gswitch *stmt, size_t start_idx, tree val, size_t *idx) |
| { |
| size_t n = gimple_switch_num_labels (stmt); |
| size_t low, high; |
| |
| /* Find case label for minimum of the value range or the next one. |
| At each iteration we are searching in [low, high - 1]. */ |
| |
| for (low = start_idx, high = n; high != low; ) |
| { |
| tree t; |
| int cmp; |
| /* Note that i != high, so we never ask for n. */ |
| size_t i = (high + low) / 2; |
| t = gimple_switch_label (stmt, i); |
| |
| /* Cache the result of comparing CASE_LOW and val. */ |
| cmp = tree_int_cst_compare (CASE_LOW (t), val); |
| |
| if (cmp == 0) |
| { |
| /* Ranges cannot be empty. */ |
| *idx = i; |
| return true; |
| } |
| else if (cmp > 0) |
| high = i; |
| else |
| { |
| low = i + 1; |
| if (CASE_HIGH (t) != NULL |
| && tree_int_cst_compare (CASE_HIGH (t), val) >= 0) |
| { |
| *idx = i; |
| return true; |
| } |
| } |
| } |
| |
| *idx = high; |
| return false; |
| } |
| |
| /* Searches the case label vector VEC for the range of CASE_LABELs that is used |
| for values between MIN and MAX. The first index is placed in MIN_IDX. The |
| last index is placed in MAX_IDX. If the range of CASE_LABELs is empty |
| then MAX_IDX < MIN_IDX. |
| Returns true if the default label is not needed. */ |
| |
| bool |
| find_case_label_range (gswitch *stmt, tree min, tree max, size_t *min_idx, |
| size_t *max_idx) |
| { |
| size_t i, j; |
| bool min_take_default = !find_case_label_index (stmt, 1, min, &i); |
| bool max_take_default = !find_case_label_index (stmt, i, max, &j); |
| |
| if (i == j |
| && min_take_default |
| && max_take_default) |
| { |
| /* Only the default case label reached. |
| Return an empty range. */ |
| *min_idx = 1; |
| *max_idx = 0; |
| return false; |
| } |
| else |
| { |
| bool take_default = min_take_default || max_take_default; |
| tree low, high; |
| size_t k; |
| |
| if (max_take_default) |
| j--; |
| |
| /* If the case label range is continuous, we do not need |
| the default case label. Verify that. */ |
| high = CASE_LOW (gimple_switch_label (stmt, i)); |
| if (CASE_HIGH (gimple_switch_label (stmt, i))) |
| high = CASE_HIGH (gimple_switch_label (stmt, i)); |
| for (k = i + 1; k <= j; ++k) |
| { |
| low = CASE_LOW (gimple_switch_label (stmt, k)); |
| if (!integer_onep (int_const_binop (MINUS_EXPR, low, high))) |
| { |
| take_default = true; |
| break; |
| } |
| high = low; |
| if (CASE_HIGH (gimple_switch_label (stmt, k))) |
| high = CASE_HIGH (gimple_switch_label (stmt, k)); |
| } |
| |
| *min_idx = i; |
| *max_idx = j; |
| return !take_default; |
| } |
| } |
| |
| /* Given a SWITCH_STMT, return the case label that encompasses the |
| known possible values for the switch operand. RANGE_OF_OP is a |
| range for the known values of the switch operand. */ |
| |
| tree |
| find_case_label_range (gswitch *switch_stmt, const irange *range_of_op) |
| { |
| if (range_of_op->undefined_p () |
| || range_of_op->varying_p () |
| || range_of_op->symbolic_p ()) |
| return NULL_TREE; |
| |
| size_t i, j; |
| tree op = gimple_switch_index (switch_stmt); |
| tree type = TREE_TYPE (op); |
| tree tmin = wide_int_to_tree (type, range_of_op->lower_bound ()); |
| tree tmax = wide_int_to_tree (type, range_of_op->upper_bound ()); |
| find_case_label_range (switch_stmt, tmin, tmax, &i, &j); |
| if (i == j) |
| { |
| /* Look for exactly one label that encompasses the range of |
| the operand. */ |
| tree label = gimple_switch_label (switch_stmt, i); |
| tree case_high |
| = CASE_HIGH (label) ? CASE_HIGH (label) : CASE_LOW (label); |
| int_range_max label_range (CASE_LOW (label), case_high); |
| if (!types_compatible_p (label_range.type (), range_of_op->type ())) |
| range_cast (label_range, range_of_op->type ()); |
| label_range.intersect (range_of_op); |
| if (label_range == *range_of_op) |
| return label; |
| } |
| else if (i > j) |
| { |
| /* If there are no labels at all, take the default. */ |
| return gimple_switch_label (switch_stmt, 0); |
| } |
| else |
| { |
| /* Otherwise, there are various labels that can encompass |
| the range of operand. In which case, see if the range of |
| the operand is entirely *outside* the bounds of all the |
| (non-default) case labels. If so, take the default. */ |
| unsigned n = gimple_switch_num_labels (switch_stmt); |
| tree min_label = gimple_switch_label (switch_stmt, 1); |
| tree max_label = gimple_switch_label (switch_stmt, n - 1); |
| tree case_high = CASE_HIGH (max_label); |
| if (!case_high) |
| case_high = CASE_LOW (max_label); |
| int_range_max label_range (CASE_LOW (min_label), case_high); |
| if (!types_compatible_p (label_range.type (), range_of_op->type ())) |
| range_cast (label_range, range_of_op->type ()); |
| label_range.intersect (range_of_op); |
| if (label_range.undefined_p ()) |
| return gimple_switch_label (switch_stmt, 0); |
| } |
| return NULL_TREE; |
| } |
| |
| struct case_info |
| { |
| tree expr; |
| basic_block bb; |
| }; |
| |
| /* Location information for ASSERT_EXPRs. Each instance of this |
| structure describes an ASSERT_EXPR for an SSA name. Since a single |
| SSA name may have more than one assertion associated with it, these |
| locations are kept in a linked list attached to the corresponding |
| SSA name. */ |
| struct assert_locus |
| { |
| /* Basic block where the assertion would be inserted. */ |
| basic_block bb; |
| |
| /* Some assertions need to be inserted on an edge (e.g., assertions |
| generated by COND_EXPRs). In those cases, BB will be NULL. */ |
| edge e; |
| |
| /* Pointer to the statement that generated this assertion. */ |
| gimple_stmt_iterator si; |
| |
| /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */ |
| enum tree_code comp_code; |
| |
| /* Value being compared against. */ |
| tree val; |
| |
| /* Expression to compare. */ |
| tree expr; |
| |
| /* Next node in the linked list. */ |
| assert_locus *next; |
| }; |
| |
| /* Class to traverse the flowgraph looking for conditional jumps to |
| insert ASSERT_EXPR range expressions. These range expressions are |
| meant to provide information to optimizations that need to reason |
| in terms of value ranges. They will not be expanded into RTL. */ |
| |
| class vrp_asserts |
| { |
| public: |
| vrp_asserts (struct function *fn) : fun (fn) { } |
| |
| void insert_range_assertions (); |
| |
| /* Convert range assertion expressions into the implied copies and |
| copy propagate away the copies. */ |
| void remove_range_assertions (); |
| |
| /* Dump all the registered assertions for all the names to FILE. */ |
| void dump (FILE *); |
| |
| /* Dump all the registered assertions for NAME to FILE. */ |
| void dump (FILE *file, tree name); |
| |
| /* Dump all the registered assertions for NAME to stderr. */ |
| void debug (tree name) |
| { |
| dump (stderr, name); |
| } |
| |
| /* Dump all the registered assertions for all the names to stderr. */ |
| void debug () |
| { |
| dump (stderr); |
| } |
| |
| private: |
| /* Set of SSA names found live during the RPO traversal of the function |
| for still active basic-blocks. */ |
| live_names live; |
| |
| /* Function to work on. */ |
| struct function *fun; |
| |
| /* If bit I is present, it means that SSA name N_i has a list of |
| assertions that should be inserted in the IL. */ |
| bitmap need_assert_for; |
| |
| /* Array of locations lists where to insert assertions. ASSERTS_FOR[I] |
| holds a list of ASSERT_LOCUS_T nodes that describe where |
| ASSERT_EXPRs for SSA name N_I should be inserted. */ |
| assert_locus **asserts_for; |
| |
| /* Finish found ASSERTS for E and register them at GSI. */ |
| void finish_register_edge_assert_for (edge e, gimple_stmt_iterator gsi, |
| vec<assert_info> &asserts); |
| |
| /* Determine whether the outgoing edges of BB should receive an |
| ASSERT_EXPR for each of the operands of BB's LAST statement. The |
| last statement of BB must be a SWITCH_EXPR. |
| |
| If any of the sub-graphs rooted at BB have an interesting use of |
| the predicate operands, an assert location node is added to the |
| list of assertions for the corresponding operands. */ |
| void find_switch_asserts (basic_block bb, gswitch *last); |
| |
| /* Do an RPO walk over the function computing SSA name liveness |
| on-the-fly and deciding on assert expressions to insert. */ |
| void find_assert_locations (); |
| |
| /* Traverse all the statements in block BB looking for statements that |
| may generate useful assertions for the SSA names in their operand. |
| See method implementation comentary for more information. */ |
| void find_assert_locations_in_bb (basic_block bb); |
| |
| /* Determine whether the outgoing edges of BB should receive an |
| ASSERT_EXPR for each of the operands of BB's LAST statement. |
| The last statement of BB must be a COND_EXPR. |
| |
| If any of the sub-graphs rooted at BB have an interesting use of |
| the predicate operands, an assert location node is added to the |
| list of assertions for the corresponding operands. */ |
| void find_conditional_asserts (basic_block bb, gcond *last); |
| |
| /* Process all the insertions registered for every name N_i registered |
| in NEED_ASSERT_FOR. The list of assertions to be inserted are |
| found in ASSERTS_FOR[i]. */ |
| void process_assert_insertions (); |
| |
| /* If NAME doesn't have an ASSERT_EXPR registered for asserting |
| 'EXPR COMP_CODE VAL' at a location that dominates block BB or |
| E->DEST, then register this location as a possible insertion point |
| for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>. |
| |
| BB, E and SI provide the exact insertion point for the new |
| ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted |
| on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on |
| BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E |
| must not be NULL. */ |
| void register_new_assert_for (tree name, tree expr, |
| enum tree_code comp_code, |
| tree val, basic_block bb, |
| edge e, gimple_stmt_iterator si); |
| |
| /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V, |
| create a new SSA name N and return the assertion assignment |
| 'N = ASSERT_EXPR <V, V OP W>'. */ |
| gimple *build_assert_expr_for (tree cond, tree v); |
| |
| /* Create an ASSERT_EXPR for NAME and insert it in the location |
| indicated by LOC. Return true if we made any edge insertions. */ |
| bool process_assert_insertions_for (tree name, assert_locus *loc); |
| |
| /* Qsort callback for sorting assert locations. */ |
| template <bool stable> static int compare_assert_loc (const void *, |
| const void *); |
| |
| /* Return false if EXPR is a predicate expression involving floating |
| point values. */ |
| bool fp_predicate (gimple *stmt) |
| { |
| GIMPLE_CHECK (stmt, GIMPLE_COND); |
| return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt))); |
| } |
| |
| bool all_imm_uses_in_stmt_or_feed_cond (tree var, gimple *stmt, |
| basic_block cond_bb); |
| |
| static int compare_case_labels (const void *, const void *); |
| }; |
| |
| /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V, |
| create a new SSA name N and return the assertion assignment |
| 'N = ASSERT_EXPR <V, V OP W>'. */ |
| |
| gimple * |
| vrp_asserts::build_assert_expr_for (tree cond, tree v) |
| { |
| tree a; |
| gassign *assertion; |
| |
| gcc_assert (TREE_CODE (v) == SSA_NAME |
| && COMPARISON_CLASS_P (cond)); |
| |
| a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond); |
| assertion = gimple_build_assign (NULL_TREE, a); |
| |
| /* The new ASSERT_EXPR, creates a new SSA name that replaces the |
| operand of the ASSERT_EXPR. Create it so the new name and the old one |
| are registered in the replacement table so that we can fix the SSA web |
| after adding all the ASSERT_EXPRs. */ |
| tree new_def = create_new_def_for (v, assertion, NULL); |
| /* Make sure we preserve abnormalness throughout an ASSERT_EXPR chain |
| given we have to be able to fully propagate those out to re-create |
| valid SSA when removing the asserts. */ |
| if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (v)) |
| SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_def) = 1; |
| |
| return assertion; |
| } |
| |
| /* Dump all the registered assertions for NAME to FILE. */ |
| |
| void |
| vrp_asserts::dump (FILE *file, tree name) |
| { |
| assert_locus *loc; |
| |
| fprintf (file, "Assertions to be inserted for "); |
| print_generic_expr (file, name); |
| fprintf (file, "\n"); |
| |
| loc = asserts_for[SSA_NAME_VERSION (name)]; |
| while (loc) |
| { |
| fprintf (file, "\t"); |
| print_gimple_stmt (file, gsi_stmt (loc->si), 0); |
| fprintf (file, "\n\tBB #%d", loc->bb->index); |
| if (loc->e) |
| { |
| fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index, |
| loc->e->dest->index); |
| dump_edge_info (file, loc->e, dump_flags, 0); |
| } |
| fprintf (file, "\n\tPREDICATE: "); |
| print_generic_expr (file, loc->expr); |
| fprintf (file, " %s ", get_tree_code_name (loc->comp_code)); |
| print_generic_expr (file, loc->val); |
| fprintf (file, "\n\n"); |
| loc = loc->next; |
| } |
| |
| fprintf (file, "\n"); |
| } |
| |
| /* Dump all the registered assertions for all the names to FILE. */ |
| |
| void |
| vrp_asserts::dump (FILE *file) |
| { |
| unsigned i; |
| bitmap_iterator bi; |
| |
| fprintf (file, "\nASSERT_EXPRs to be inserted\n\n"); |
| EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi) |
| dump (file, ssa_name (i)); |
| fprintf (file, "\n"); |
| } |
| |
| /* If NAME doesn't have an ASSERT_EXPR registered for asserting |
| 'EXPR COMP_CODE VAL' at a location that dominates block BB or |
| E->DEST, then register this location as a possible insertion point |
| for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>. |
| |
| BB, E and SI provide the exact insertion point for the new |
| ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted |
| on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on |
| BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E |
| must not be NULL. */ |
| |
| void |
| vrp_asserts::register_new_assert_for (tree name, tree expr, |
| enum tree_code comp_code, |
| tree val, |
| basic_block bb, |
| edge e, |
| gimple_stmt_iterator si) |
| { |
| assert_locus *n, *loc, *last_loc; |
| basic_block dest_bb; |
| |
| gcc_checking_assert (bb == NULL || e == NULL); |
| |
| if (e == NULL) |
| gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND |
| && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH); |
| |
| /* Never build an assert comparing against an integer constant with |
| TREE_OVERFLOW set. This confuses our undefined overflow warning |
| machinery. */ |
| if (TREE_OVERFLOW_P (val)) |
| val = drop_tree_overflow (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, |
| assume that A will be inserted at E->DEST. Note that this is not |
| necessarily true. |
| |
| If E is a critical edge, it will be split. But even if E is |
| split, the new block will dominate the same set of blocks that |
| E->DEST dominates. |
| |
| The reverse, however, is not true, blocks dominated by E->DEST |
| will not be dominated by the new block created to split E. So, |
| if the insertion location is on a critical edge, we will not use |
| the new location to move another assertion previously registered |
| at a block dominated by E->DEST. */ |
| dest_bb = (bb) ? bb : e->dest; |
| |
| /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and |
| VAL at a block dominating DEST_BB, then we don't need to insert a new |
| one. Similarly, if the same assertion already exists at a block |
| dominated by DEST_BB and the new location is not on a critical |
| edge, then update the existing location for the assertion (i.e., |
| move the assertion up in the dominance tree). |
| |
| Note, this is implemented as a simple linked list because there |
| should not be more than a handful of assertions registered per |
| name. If this becomes a performance problem, a table hashed by |
| COMP_CODE and VAL could be implemented. */ |
| loc = asserts_for[SSA_NAME_VERSION (name)]; |
| last_loc = loc; |
| while (loc) |
| { |
| if (loc->comp_code == comp_code |
| && (loc->val == val |
| || operand_equal_p (loc->val, val, 0)) |
| && (loc->expr == expr |
| || operand_equal_p (loc->expr, expr, 0))) |
| { |
| /* If E is not a critical edge and DEST_BB |
| dominates the existing location for the assertion, move |
| the assertion up in the dominance tree by updating its |
| location information. */ |
| if ((e == NULL || !EDGE_CRITICAL_P (e)) |
| && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb)) |
| { |
| loc->bb = dest_bb; |
| loc->e = e; |
| loc->si = si; |
| return; |
| } |
| } |
| |
| /* Update the last node of the list and move to the next one. */ |
| last_loc = loc; |
| loc = loc->next; |
| } |
| |
| /* If we didn't find an assertion already registered for |
| NAME COMP_CODE VAL, add a new one at the end of the list of |
| assertions associated with NAME. */ |
| n = XNEW (struct assert_locus); |
| n->bb = dest_bb; |
| n->e = e; |
| n->si = si; |
| n->comp_code = comp_code; |
| n->val = val; |
| n->expr = expr; |
| n->next = NULL; |
| |
| if (last_loc) |
| last_loc->next = n; |
| else |
| asserts_for[SSA_NAME_VERSION (name)] = n; |
| |
| bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name)); |
| } |
| |
| /* Finish found ASSERTS for E and register them at GSI. */ |
| |
| void |
| vrp_asserts::finish_register_edge_assert_for (edge e, |
| gimple_stmt_iterator gsi, |
| vec<assert_info> &asserts) |
| { |
| for (unsigned i = 0; i < asserts.length (); ++i) |
| /* Only register an ASSERT_EXPR if NAME was found in the sub-graph |
| reachable from E. */ |
| if (live.live_on_edge_p (asserts[i].name, e)) |
| register_new_assert_for (asserts[i].name, asserts[i].expr, |
| asserts[i].comp_code, asserts[i].val, |
| NULL, e, gsi); |
| } |
| |
| /* Determine whether the outgoing edges of BB should receive an |
| ASSERT_EXPR for each of the operands of BB's LAST statement. |
| The last statement of BB must be a COND_EXPR. |
| |
| If any of the sub-graphs rooted at BB have an interesting use of |
| the predicate operands, an assert location node is added to the |
| list of assertions for the corresponding operands. */ |
| |
| void |
| vrp_asserts::find_conditional_asserts (basic_block bb, gcond *last) |
| { |
| gimple_stmt_iterator bsi; |
| tree op; |
| edge_iterator ei; |
| edge e; |
| ssa_op_iter iter; |
| |
| bsi = gsi_for_stmt (last); |
| |
| /* Look for uses of the operands in each of the sub-graphs |
| rooted at BB. We need to check each of the outgoing edges |
| separately, so that we know what kind of ASSERT_EXPR to |
| insert. */ |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| { |
| if (e->dest == bb) |
| continue; |
| |
| /* Register the necessary assertions for each operand in the |
| conditional predicate. */ |
| auto_vec<assert_info, 8> asserts; |
| FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE) |
| register_edge_assert_for (op, e, |
| gimple_cond_code (last), |
| gimple_cond_lhs (last), |
| gimple_cond_rhs (last), asserts); |
| finish_register_edge_assert_for (e, bsi, asserts); |
| } |
| } |
| |
| /* Compare two case labels sorting first by the destination bb index |
| and then by the case value. */ |
| |
| int |
| vrp_asserts::compare_case_labels (const void *p1, const void *p2) |
| { |
| const struct case_info *ci1 = (const struct case_info *) p1; |
| const struct case_info *ci2 = (const struct case_info *) p2; |
| int idx1 = ci1->bb->index; |
| int idx2 = ci2->bb->index; |
| |
| if (idx1 < idx2) |
| return -1; |
| else if (idx1 == idx2) |
| { |
| /* Make sure the default label is first in a group. */ |
| if (!CASE_LOW (ci1->expr)) |
| return -1; |
| else if (!CASE_LOW (ci2->expr)) |
| return 1; |
| else |
| return tree_int_cst_compare (CASE_LOW (ci1->expr), |
| CASE_LOW (ci2->expr)); |
| } |
| else |
| return 1; |
| } |
| |
| /* Determine whether the outgoing edges of BB should receive an |
| ASSERT_EXPR for each of the operands of BB's LAST statement. |
| The last statement of BB must be a SWITCH_EXPR. |
| |
| If any of the sub-graphs rooted at BB have an interesting use of |
| the predicate operands, an assert location node is added to the |
| list of assertions for the corresponding operands. */ |
| |
| void |
| vrp_asserts::find_switch_asserts (basic_block bb, gswitch *last) |
| { |
| gimple_stmt_iterator bsi; |
| tree op; |
| edge e; |
| struct case_info *ci; |
| 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 |
| |
| bsi = gsi_for_stmt (last); |
| op = gimple_switch_index (last); |
| if (TREE_CODE (op) != SSA_NAME) |
| return; |
| |
| /* Build a vector of case labels sorted by destination label. */ |
| ci = XNEWVEC (struct case_info, n); |
| for (idx = 0; idx < n; ++idx) |
| { |
| ci[idx].expr = gimple_switch_label (last, idx); |
| ci[idx].bb = label_to_block (fun, CASE_LABEL (ci[idx].expr)); |
| } |
| edge default_edge = find_edge (bb, ci[0].bb); |
| qsort (ci, n, sizeof (struct case_info), compare_case_labels); |
| |
| for (idx = 0; idx < n; ++idx) |
| { |
| tree min, max; |
| tree cl = ci[idx].expr; |
| basic_block cbb = ci[idx].bb; |
| |
| min = CASE_LOW (cl); |
| max = CASE_HIGH (cl); |
| |
| /* If there are multiple case labels with the same destination |
| we need to combine them to a single value range for the edge. */ |
| if (idx + 1 < n && cbb == ci[idx + 1].bb) |
| { |
| /* Skip labels until the last of the group. */ |
| do { |
| ++idx; |
| } while (idx < n && cbb == ci[idx].bb); |
| --idx; |
| |
| /* Pick up the maximum of the case label range. */ |
| if (CASE_HIGH (ci[idx].expr)) |
| max = CASE_HIGH (ci[idx].expr); |
| else |
| max = CASE_LOW (ci[idx].expr); |
| } |
| |
| /* Can't extract a useful assertion out of a range that includes the |
| default label. */ |
| if (min == NULL_TREE) |
| continue; |
| |
| /* Find the edge to register the assert expr on. */ |
| e = find_edge (bb, cbb); |
| |
| /* Register the necessary assertions for the operand in the |
| SWITCH_EXPR. */ |
| auto_vec<assert_info, 8> asserts; |
| register_edge_assert_for (op, e, |
| max ? GE_EXPR : EQ_EXPR, |
| op, fold_convert (TREE_TYPE (op), min), |
| asserts); |
| if (max) |
| register_edge_assert_for (op, e, LE_EXPR, op, |
| fold_convert (TREE_TYPE (op), max), |
| asserts); |
| finish_register_edge_assert_for (e, bsi, asserts); |
| } |
| |
| XDELETEVEC (ci); |
| |
| if (!live.live_on_edge_p (op, default_edge)) |
| return; |
| |
| /* Now register along the default label assertions that correspond to the |
| anti-range of each label. */ |
| int insertion_limit = param_max_vrp_switch_assertions; |
| if (insertion_limit == 0) |
| return; |
| |
| /* We can't do this if the default case shares a label with another case. */ |
| tree default_cl = gimple_switch_default_label (last); |
| for (idx = 1; idx < n; idx++) |
| { |
| tree min, max; |
| tree cl = gimple_switch_label (last, idx); |
| if (CASE_LABEL (cl) == CASE_LABEL (default_cl)) |
| continue; |
| |
| min = CASE_LOW (cl); |
| max = CASE_HIGH (cl); |
| |
| /* Combine contiguous case ranges to reduce the number of assertions |
| to insert. */ |
| for (idx = idx + 1; idx < n; idx++) |
| { |
| tree next_min, next_max; |
| tree next_cl = gimple_switch_label (last, idx); |
| if (CASE_LABEL (next_cl) == CASE_LABEL (default_cl)) |
| break; |
| |
| next_min = CASE_LOW (next_cl); |
| next_max = CASE_HIGH (next_cl); |
| |
| wide_int difference = (wi::to_wide (next_min) |
| - wi::to_wide (max ? max : min)); |
| if (wi::eq_p (difference, 1)) |
| max = next_max ? next_max : next_min; |
| else |
| break; |
| } |
| idx--; |
| |
| if (max == NULL_TREE) |
| { |
| /* Register the assertion OP != MIN. */ |
| auto_vec<assert_info, 8> asserts; |
| min = fold_convert (TREE_TYPE (op), min); |
| register_edge_assert_for (op, default_edge, NE_EXPR, op, min, |
| asserts); |
| finish_register_edge_assert_for (default_edge, bsi, asserts); |
| } |
| else |
| { |
| /* Register the assertion (unsigned)OP - MIN > (MAX - MIN), |
| which will give OP the anti-range ~[MIN,MAX]. */ |
| tree uop = fold_convert (unsigned_type_for (TREE_TYPE (op)), op); |
| min = fold_convert (TREE_TYPE (uop), min); |
| max = fold_convert (TREE_TYPE (uop), max); |
| |
| tree lhs = fold_build2 (MINUS_EXPR, TREE_TYPE (uop), uop, min); |
| tree rhs = int_const_binop (MINUS_EXPR, max, min); |
| register_new_assert_for (op, lhs, GT_EXPR, rhs, |
| NULL, default_edge, bsi); |
| } |
| |
| if (--insertion_limit == 0) |
| break; |
| } |
| } |
| |
| /* Traverse all the statements in block BB looking for statements that |
| may generate useful assertions for the SSA names in their operand. |
| If a statement produces a useful assertion A for name N_i, then the |
| list of assertions already generated for N_i is scanned to |
| determine if A is actually needed. |
| |
| If N_i already had the assertion A at a location dominating the |
| current location, then nothing needs to be done. Otherwise, the |
| new location for A is recorded instead. |
| |
| 1- For every statement S in BB, all the variables used by S are |
| added to bitmap FOUND_IN_SUBGRAPH. |
| |
| 2- If statement S uses an operand N in a way that exposes a known |
| value range for N, then if N was not already generated by an |
| ASSERT_EXPR, create a new assert location for N. For instance, |
| if N is a pointer and the statement dereferences it, we can |
| assume that N is not NULL. |
| |
| 3- COND_EXPRs are a special case of #2. We can derive range |
| information from the predicate but need to insert different |
| ASSERT_EXPRs for each of the sub-graphs rooted at the |
| conditional block. If the last statement of BB is a conditional |
| expression of the form 'X op Y', then |
| |
| a) Remove X and Y from the set FOUND_IN_SUBGRAPH. |
| |
| b) If the conditional is the only entry point to the sub-graph |
| corresponding to the THEN_CLAUSE, recurse into it. On |
| return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then |
| an ASSERT_EXPR is added for the corresponding variable. |
| |
| c) Repeat step (b) on the ELSE_CLAUSE. |
| |
| d) Mark X and Y in FOUND_IN_SUBGRAPH. |
|