| /* Chains of recurrences. |
| Copyright (C) 2003-2017 Free Software Foundation, Inc. |
| Contributed by Sebastian Pop <pop@cri.ensmp.fr> |
| |
| 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/>. */ |
| |
| /* This file implements operations on chains of recurrences. Chains |
| of recurrences are used for modeling evolution functions of scalar |
| variables. |
| */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "tree.h" |
| #include "gimple-expr.h" |
| #include "tree-pretty-print.h" |
| #include "fold-const.h" |
| #include "cfgloop.h" |
| #include "tree-ssa-loop-ivopts.h" |
| #include "tree-ssa-loop-niter.h" |
| #include "tree-chrec.h" |
| #include "dumpfile.h" |
| #include "params.h" |
| #include "tree-scalar-evolution.h" |
| |
| /* Extended folder for chrecs. */ |
| |
| /* Determines whether CST is not a constant evolution. */ |
| |
| static inline bool |
| is_not_constant_evolution (const_tree cst) |
| { |
| return (TREE_CODE (cst) == POLYNOMIAL_CHREC); |
| } |
| |
| /* Fold CODE for a polynomial function and a constant. */ |
| |
| static inline tree |
| chrec_fold_poly_cst (enum tree_code code, |
| tree type, |
| tree poly, |
| tree cst) |
| { |
| gcc_assert (poly); |
| gcc_assert (cst); |
| gcc_assert (TREE_CODE (poly) == POLYNOMIAL_CHREC); |
| gcc_checking_assert (!is_not_constant_evolution (cst)); |
| gcc_checking_assert (useless_type_conversion_p (type, chrec_type (poly))); |
| |
| switch (code) |
| { |
| case PLUS_EXPR: |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (poly), |
| chrec_fold_plus (type, CHREC_LEFT (poly), cst), |
| CHREC_RIGHT (poly)); |
| |
| case MINUS_EXPR: |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (poly), |
| chrec_fold_minus (type, CHREC_LEFT (poly), cst), |
| CHREC_RIGHT (poly)); |
| |
| case MULT_EXPR: |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (poly), |
| chrec_fold_multiply (type, CHREC_LEFT (poly), cst), |
| chrec_fold_multiply (type, CHREC_RIGHT (poly), cst)); |
| |
| default: |
| return chrec_dont_know; |
| } |
| } |
| |
| /* Fold the addition of two polynomial functions. */ |
| |
| static inline tree |
| chrec_fold_plus_poly_poly (enum tree_code code, |
| tree type, |
| tree poly0, |
| tree poly1) |
| { |
| tree left, right; |
| struct loop *loop0 = get_chrec_loop (poly0); |
| struct loop *loop1 = get_chrec_loop (poly1); |
| tree rtype = code == POINTER_PLUS_EXPR ? chrec_type (poly1) : type; |
| |
| gcc_assert (poly0); |
| gcc_assert (poly1); |
| gcc_assert (TREE_CODE (poly0) == POLYNOMIAL_CHREC); |
| gcc_assert (TREE_CODE (poly1) == POLYNOMIAL_CHREC); |
| if (POINTER_TYPE_P (chrec_type (poly0))) |
| gcc_checking_assert (ptrofftype_p (chrec_type (poly1)) |
| && useless_type_conversion_p (type, chrec_type (poly0))); |
| else |
| gcc_checking_assert (useless_type_conversion_p (type, chrec_type (poly0)) |
| && useless_type_conversion_p (type, chrec_type (poly1))); |
| |
| /* |
| {a, +, b}_1 + {c, +, d}_2 -> {{a, +, b}_1 + c, +, d}_2, |
| {a, +, b}_2 + {c, +, d}_1 -> {{c, +, d}_1 + a, +, b}_2, |
| {a, +, b}_x + {c, +, d}_x -> {a+c, +, b+d}_x. */ |
| if (flow_loop_nested_p (loop0, loop1)) |
| { |
| if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR) |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (poly1), |
| chrec_fold_plus (type, poly0, CHREC_LEFT (poly1)), |
| CHREC_RIGHT (poly1)); |
| else |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (poly1), |
| chrec_fold_minus (type, poly0, CHREC_LEFT (poly1)), |
| chrec_fold_multiply (type, CHREC_RIGHT (poly1), |
| SCALAR_FLOAT_TYPE_P (type) |
| ? build_real (type, dconstm1) |
| : build_int_cst_type (type, -1))); |
| } |
| |
| if (flow_loop_nested_p (loop1, loop0)) |
| { |
| if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR) |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (poly0), |
| chrec_fold_plus (type, CHREC_LEFT (poly0), poly1), |
| CHREC_RIGHT (poly0)); |
| else |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (poly0), |
| chrec_fold_minus (type, CHREC_LEFT (poly0), poly1), |
| CHREC_RIGHT (poly0)); |
| } |
| |
| /* This function should never be called for chrecs of loops that |
| do not belong to the same loop nest. */ |
| if (loop0 != loop1) |
| { |
| /* It still can happen if we are not in loop-closed SSA form. */ |
| gcc_assert (! loops_state_satisfies_p (LOOP_CLOSED_SSA)); |
| return chrec_dont_know; |
| } |
| |
| if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR) |
| { |
| left = chrec_fold_plus |
| (type, CHREC_LEFT (poly0), CHREC_LEFT (poly1)); |
| right = chrec_fold_plus |
| (rtype, CHREC_RIGHT (poly0), CHREC_RIGHT (poly1)); |
| } |
| else |
| { |
| left = chrec_fold_minus |
| (type, CHREC_LEFT (poly0), CHREC_LEFT (poly1)); |
| right = chrec_fold_minus |
| (type, CHREC_RIGHT (poly0), CHREC_RIGHT (poly1)); |
| } |
| |
| if (chrec_zerop (right)) |
| return left; |
| else |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (poly0), left, right); |
| } |
| |
| |
| |
| /* Fold the multiplication of two polynomial functions. */ |
| |
| static inline tree |
| chrec_fold_multiply_poly_poly (tree type, |
| tree poly0, |
| tree poly1) |
| { |
| tree t0, t1, t2; |
| int var; |
| struct loop *loop0 = get_chrec_loop (poly0); |
| struct loop *loop1 = get_chrec_loop (poly1); |
| |
| gcc_assert (poly0); |
| gcc_assert (poly1); |
| gcc_assert (TREE_CODE (poly0) == POLYNOMIAL_CHREC); |
| gcc_assert (TREE_CODE (poly1) == POLYNOMIAL_CHREC); |
| gcc_checking_assert (useless_type_conversion_p (type, chrec_type (poly0)) |
| && useless_type_conversion_p (type, chrec_type (poly1))); |
| |
| /* {a, +, b}_1 * {c, +, d}_2 -> {c*{a, +, b}_1, +, d}_2, |
| {a, +, b}_2 * {c, +, d}_1 -> {a*{c, +, d}_1, +, b}_2, |
| {a, +, b}_x * {c, +, d}_x -> {a*c, +, a*d + b*c + b*d, +, 2*b*d}_x. */ |
| if (flow_loop_nested_p (loop0, loop1)) |
| /* poly0 is a constant wrt. poly1. */ |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (poly1), |
| chrec_fold_multiply (type, CHREC_LEFT (poly1), poly0), |
| CHREC_RIGHT (poly1)); |
| |
| if (flow_loop_nested_p (loop1, loop0)) |
| /* poly1 is a constant wrt. poly0. */ |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (poly0), |
| chrec_fold_multiply (type, CHREC_LEFT (poly0), poly1), |
| CHREC_RIGHT (poly0)); |
| |
| if (loop0 != loop1) |
| { |
| /* It still can happen if we are not in loop-closed SSA form. */ |
| gcc_assert (! loops_state_satisfies_p (LOOP_CLOSED_SSA)); |
| return chrec_dont_know; |
| } |
| |
| /* poly0 and poly1 are two polynomials in the same variable, |
| {a, +, b}_x * {c, +, d}_x -> {a*c, +, a*d + b*c + b*d, +, 2*b*d}_x. */ |
| |
| /* "a*c". */ |
| t0 = chrec_fold_multiply (type, CHREC_LEFT (poly0), CHREC_LEFT (poly1)); |
| |
| /* "a*d + b*c". */ |
| t1 = chrec_fold_multiply (type, CHREC_LEFT (poly0), CHREC_RIGHT (poly1)); |
| t1 = chrec_fold_plus (type, t1, chrec_fold_multiply (type, |
| CHREC_RIGHT (poly0), |
| CHREC_LEFT (poly1))); |
| /* "b*d". */ |
| t2 = chrec_fold_multiply (type, CHREC_RIGHT (poly0), CHREC_RIGHT (poly1)); |
| /* "a*d + b*c + b*d". */ |
| t1 = chrec_fold_plus (type, t1, t2); |
| /* "2*b*d". */ |
| t2 = chrec_fold_multiply (type, SCALAR_FLOAT_TYPE_P (type) |
| ? build_real (type, dconst2) |
| : build_int_cst (type, 2), t2); |
| |
| var = CHREC_VARIABLE (poly0); |
| return build_polynomial_chrec (var, t0, |
| build_polynomial_chrec (var, t1, t2)); |
| } |
| |
| /* When the operands are automatically_generated_chrec_p, the fold has |
| to respect the semantics of the operands. */ |
| |
| static inline tree |
| chrec_fold_automatically_generated_operands (tree op0, |
| tree op1) |
| { |
| if (op0 == chrec_dont_know |
| || op1 == chrec_dont_know) |
| return chrec_dont_know; |
| |
| if (op0 == chrec_known |
| || op1 == chrec_known) |
| return chrec_known; |
| |
| if (op0 == chrec_not_analyzed_yet |
| || op1 == chrec_not_analyzed_yet) |
| return chrec_not_analyzed_yet; |
| |
| /* The default case produces a safe result. */ |
| return chrec_dont_know; |
| } |
| |
| /* Fold the addition of two chrecs. */ |
| |
| static tree |
| chrec_fold_plus_1 (enum tree_code code, tree type, |
| tree op0, tree op1) |
| { |
| if (automatically_generated_chrec_p (op0) |
| || automatically_generated_chrec_p (op1)) |
| return chrec_fold_automatically_generated_operands (op0, op1); |
| |
| switch (TREE_CODE (op0)) |
| { |
| case POLYNOMIAL_CHREC: |
| gcc_checking_assert |
| (!chrec_contains_symbols_defined_in_loop (op0, CHREC_VARIABLE (op0))); |
| switch (TREE_CODE (op1)) |
| { |
| case POLYNOMIAL_CHREC: |
| gcc_checking_assert |
| (!chrec_contains_symbols_defined_in_loop (op1, |
| CHREC_VARIABLE (op1))); |
| return chrec_fold_plus_poly_poly (code, type, op0, op1); |
| |
| CASE_CONVERT: |
| if (tree_contains_chrecs (op1, NULL)) |
| return chrec_dont_know; |
| /* FALLTHRU */ |
| |
| default: |
| if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR) |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (op0), |
| chrec_fold_plus (type, CHREC_LEFT (op0), op1), |
| CHREC_RIGHT (op0)); |
| else |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (op0), |
| chrec_fold_minus (type, CHREC_LEFT (op0), op1), |
| CHREC_RIGHT (op0)); |
| } |
| |
| CASE_CONVERT: |
| if (tree_contains_chrecs (op0, NULL)) |
| return chrec_dont_know; |
| /* FALLTHRU */ |
| |
| default: |
| switch (TREE_CODE (op1)) |
| { |
| case POLYNOMIAL_CHREC: |
| gcc_checking_assert |
| (!chrec_contains_symbols_defined_in_loop (op1, |
| CHREC_VARIABLE (op1))); |
| if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR) |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (op1), |
| chrec_fold_plus (type, op0, CHREC_LEFT (op1)), |
| CHREC_RIGHT (op1)); |
| else |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (op1), |
| chrec_fold_minus (type, op0, CHREC_LEFT (op1)), |
| chrec_fold_multiply (type, CHREC_RIGHT (op1), |
| SCALAR_FLOAT_TYPE_P (type) |
| ? build_real (type, dconstm1) |
| : build_int_cst_type (type, -1))); |
| |
| CASE_CONVERT: |
| if (tree_contains_chrecs (op1, NULL)) |
| return chrec_dont_know; |
| /* FALLTHRU */ |
| |
| default: |
| { |
| int size = 0; |
| if ((tree_contains_chrecs (op0, &size) |
| || tree_contains_chrecs (op1, &size)) |
| && size < PARAM_VALUE (PARAM_SCEV_MAX_EXPR_SIZE)) |
| return build2 (code, type, op0, op1); |
| else if (size < PARAM_VALUE (PARAM_SCEV_MAX_EXPR_SIZE)) |
| { |
| if (code == POINTER_PLUS_EXPR) |
| return fold_build_pointer_plus (fold_convert (type, op0), |
| op1); |
| else |
| return fold_build2 (code, type, |
| fold_convert (type, op0), |
| fold_convert (type, op1)); |
| } |
| else |
| return chrec_dont_know; |
| } |
| } |
| } |
| } |
| |
| /* Fold the addition of two chrecs. */ |
| |
| tree |
| chrec_fold_plus (tree type, |
| tree op0, |
| tree op1) |
| { |
| enum tree_code code; |
| if (automatically_generated_chrec_p (op0) |
| || automatically_generated_chrec_p (op1)) |
| return chrec_fold_automatically_generated_operands (op0, op1); |
| |
| if (integer_zerop (op0)) |
| return chrec_convert (type, op1, NULL); |
| if (integer_zerop (op1)) |
| return chrec_convert (type, op0, NULL); |
| |
| if (POINTER_TYPE_P (type)) |
| code = POINTER_PLUS_EXPR; |
| else |
| code = PLUS_EXPR; |
| |
| return chrec_fold_plus_1 (code, type, op0, op1); |
| } |
| |
| /* Fold the subtraction of two chrecs. */ |
| |
| tree |
| chrec_fold_minus (tree type, |
| tree op0, |
| tree op1) |
| { |
| if (automatically_generated_chrec_p (op0) |
| || automatically_generated_chrec_p (op1)) |
| return chrec_fold_automatically_generated_operands (op0, op1); |
| |
| if (integer_zerop (op1)) |
| return op0; |
| |
| return chrec_fold_plus_1 (MINUS_EXPR, type, op0, op1); |
| } |
| |
| /* Fold the multiplication of two chrecs. */ |
| |
| tree |
| chrec_fold_multiply (tree type, |
| tree op0, |
| tree op1) |
| { |
| if (automatically_generated_chrec_p (op0) |
| || automatically_generated_chrec_p (op1)) |
| return chrec_fold_automatically_generated_operands (op0, op1); |
| |
| switch (TREE_CODE (op0)) |
| { |
| case POLYNOMIAL_CHREC: |
| gcc_checking_assert |
| (!chrec_contains_symbols_defined_in_loop (op0, CHREC_VARIABLE (op0))); |
| switch (TREE_CODE (op1)) |
| { |
| case POLYNOMIAL_CHREC: |
| gcc_checking_assert |
| (!chrec_contains_symbols_defined_in_loop (op1, |
| CHREC_VARIABLE (op1))); |
| return chrec_fold_multiply_poly_poly (type, op0, op1); |
| |
| CASE_CONVERT: |
| if (tree_contains_chrecs (op1, NULL)) |
| return chrec_dont_know; |
| /* FALLTHRU */ |
| |
| default: |
| if (integer_onep (op1)) |
| return op0; |
| if (integer_zerop (op1)) |
| return build_int_cst (type, 0); |
| |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (op0), |
| chrec_fold_multiply (type, CHREC_LEFT (op0), op1), |
| chrec_fold_multiply (type, CHREC_RIGHT (op0), op1)); |
| } |
| |
| CASE_CONVERT: |
| if (tree_contains_chrecs (op0, NULL)) |
| return chrec_dont_know; |
| /* FALLTHRU */ |
| |
| default: |
| if (integer_onep (op0)) |
| return op1; |
| |
| if (integer_zerop (op0)) |
| return build_int_cst (type, 0); |
| |
| switch (TREE_CODE (op1)) |
| { |
| case POLYNOMIAL_CHREC: |
| gcc_checking_assert |
| (!chrec_contains_symbols_defined_in_loop (op1, |
| CHREC_VARIABLE (op1))); |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (op1), |
| chrec_fold_multiply (type, CHREC_LEFT (op1), op0), |
| chrec_fold_multiply (type, CHREC_RIGHT (op1), op0)); |
| |
| CASE_CONVERT: |
| if (tree_contains_chrecs (op1, NULL)) |
| return chrec_dont_know; |
| /* FALLTHRU */ |
| |
| default: |
| if (integer_onep (op1)) |
| return op0; |
| if (integer_zerop (op1)) |
| return build_int_cst (type, 0); |
| return fold_build2 (MULT_EXPR, type, op0, op1); |
| } |
| } |
| } |
| |
| |
| |
| /* Operations. */ |
| |
| /* Evaluate the binomial coefficient. Return NULL_TREE if the intermediate |
| calculation overflows, otherwise return C(n,k) with type TYPE. */ |
| |
| static tree |
| tree_fold_binomial (tree type, tree n, unsigned int k) |
| { |
| bool overflow; |
| unsigned int i; |
| |
| /* Handle the most frequent cases. */ |
| if (k == 0) |
| return build_int_cst (type, 1); |
| if (k == 1) |
| return fold_convert (type, n); |
| |
| widest_int num = wi::to_widest (n); |
| |
| /* Check that k <= n. */ |
| if (wi::ltu_p (num, k)) |
| return NULL_TREE; |
| |
| /* Denominator = 2. */ |
| widest_int denom = 2; |
| |
| /* Index = Numerator-1. */ |
| widest_int idx = num - 1; |
| |
| /* Numerator = Numerator*Index = n*(n-1). */ |
| num = wi::smul (num, idx, &overflow); |
| if (overflow) |
| return NULL_TREE; |
| |
| for (i = 3; i <= k; i++) |
| { |
| /* Index--. */ |
| --idx; |
| |
| /* Numerator *= Index. */ |
| num = wi::smul (num, idx, &overflow); |
| if (overflow) |
| return NULL_TREE; |
| |
| /* Denominator *= i. */ |
| denom *= i; |
| } |
| |
| /* Result = Numerator / Denominator. */ |
| num = wi::udiv_trunc (num, denom); |
| if (! wi::fits_to_tree_p (num, type)) |
| return NULL_TREE; |
| return wide_int_to_tree (type, num); |
| } |
| |
| /* Helper function. Use the Newton's interpolating formula for |
| evaluating the value of the evolution function. |
| The result may be in an unsigned type of CHREC. */ |
| |
| static tree |
| chrec_evaluate (unsigned var, tree chrec, tree n, unsigned int k) |
| { |
| tree arg0, arg1, binomial_n_k; |
| tree type = TREE_TYPE (chrec); |
| struct loop *var_loop = get_loop (cfun, var); |
| |
| while (TREE_CODE (chrec) == POLYNOMIAL_CHREC |
| && flow_loop_nested_p (var_loop, get_chrec_loop (chrec))) |
| chrec = CHREC_LEFT (chrec); |
| |
| /* The formula associates the expression and thus we have to make |
| sure to not introduce undefined overflow. */ |
| tree ctype = type; |
| if (INTEGRAL_TYPE_P (type) |
| && ! TYPE_OVERFLOW_WRAPS (type)) |
| ctype = unsigned_type_for (type); |
| |
| if (TREE_CODE (chrec) == POLYNOMIAL_CHREC |
| && CHREC_VARIABLE (chrec) == var) |
| { |
| arg1 = chrec_evaluate (var, CHREC_RIGHT (chrec), n, k + 1); |
| if (arg1 == chrec_dont_know) |
| return chrec_dont_know; |
| binomial_n_k = tree_fold_binomial (ctype, n, k); |
| if (!binomial_n_k) |
| return chrec_dont_know; |
| tree l = chrec_convert (ctype, CHREC_LEFT (chrec), NULL); |
| arg0 = fold_build2 (MULT_EXPR, ctype, l, binomial_n_k); |
| return chrec_fold_plus (ctype, arg0, arg1); |
| } |
| |
| binomial_n_k = tree_fold_binomial (ctype, n, k); |
| if (!binomial_n_k) |
| return chrec_dont_know; |
| |
| return fold_build2 (MULT_EXPR, ctype, |
| chrec_convert (ctype, chrec, NULL), binomial_n_k); |
| } |
| |
| /* Evaluates "CHREC (X)" when the varying variable is VAR. |
| Example: Given the following parameters, |
| |
| var = 1 |
| chrec = {3, +, 4}_1 |
| x = 10 |
| |
| The result is given by the Newton's interpolating formula: |
| 3 * \binom{10}{0} + 4 * \binom{10}{1}. |
| */ |
| |
| tree |
| chrec_apply (unsigned var, |
| tree chrec, |
| tree x) |
| { |
| tree type = chrec_type (chrec); |
| tree res = chrec_dont_know; |
| |
| if (automatically_generated_chrec_p (chrec) |
| || automatically_generated_chrec_p (x) |
| |
| /* When the symbols are defined in an outer loop, it is possible |
| to symbolically compute the apply, since the symbols are |
| constants with respect to the varying loop. */ |
| || chrec_contains_symbols_defined_in_loop (chrec, var)) |
| return chrec_dont_know; |
| |
| if (dump_file && (dump_flags & TDF_SCEV)) |
| fprintf (dump_file, "(chrec_apply \n"); |
| |
| if (TREE_CODE (x) == INTEGER_CST && SCALAR_FLOAT_TYPE_P (type)) |
| x = build_real_from_int_cst (type, x); |
| |
| switch (TREE_CODE (chrec)) |
| { |
| case POLYNOMIAL_CHREC: |
| if (evolution_function_is_affine_p (chrec)) |
| { |
| if (CHREC_VARIABLE (chrec) != var) |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (chrec), |
| chrec_apply (var, CHREC_LEFT (chrec), x), |
| chrec_apply (var, CHREC_RIGHT (chrec), x)); |
| |
| /* "{a, +, b} (x)" -> "a + b*x". */ |
| x = chrec_convert_rhs (type, x, NULL); |
| res = chrec_fold_multiply (TREE_TYPE (x), CHREC_RIGHT (chrec), x); |
| res = chrec_fold_plus (type, CHREC_LEFT (chrec), res); |
| } |
| else if (TREE_CODE (x) == INTEGER_CST |
| && tree_int_cst_sgn (x) == 1) |
| /* testsuite/.../ssa-chrec-38.c. */ |
| res = chrec_convert (type, chrec_evaluate (var, chrec, x, 0), NULL); |
| else |
| res = chrec_dont_know; |
| break; |
| |
| CASE_CONVERT: |
| res = chrec_convert (TREE_TYPE (chrec), |
| chrec_apply (var, TREE_OPERAND (chrec, 0), x), |
| NULL); |
| break; |
| |
| default: |
| res = chrec; |
| break; |
| } |
| |
| if (dump_file && (dump_flags & TDF_SCEV)) |
| { |
| fprintf (dump_file, " (varying_loop = %d\n", var); |
| fprintf (dump_file, ")\n (chrec = "); |
| print_generic_expr (dump_file, chrec); |
| fprintf (dump_file, ")\n (x = "); |
| print_generic_expr (dump_file, x); |
| fprintf (dump_file, ")\n (res = "); |
| print_generic_expr (dump_file, res); |
| fprintf (dump_file, "))\n"); |
| } |
| |
| return res; |
| } |
| |
| /* For a given CHREC and an induction variable map IV_MAP that maps |
| (loop->num, expr) for every loop number of the current_loops an |
| expression, calls chrec_apply when the expression is not NULL. */ |
| |
| tree |
| chrec_apply_map (tree chrec, vec<tree> iv_map) |
| { |
| int i; |
| tree expr; |
| |
| FOR_EACH_VEC_ELT (iv_map, i, expr) |
| if (expr) |
| chrec = chrec_apply (i, chrec, expr); |
| |
| return chrec; |
| } |
| |
| /* Replaces the initial condition in CHREC with INIT_COND. */ |
| |
| tree |
| chrec_replace_initial_condition (tree chrec, |
| tree init_cond) |
| { |
| if (automatically_generated_chrec_p (chrec)) |
| return chrec; |
| |
| gcc_assert (chrec_type (chrec) == chrec_type (init_cond)); |
| |
| switch (TREE_CODE (chrec)) |
| { |
| case POLYNOMIAL_CHREC: |
| return build_polynomial_chrec |
| (CHREC_VARIABLE (chrec), |
| chrec_replace_initial_condition (CHREC_LEFT (chrec), init_cond), |
| CHREC_RIGHT (chrec)); |
| |
| default: |
| return init_cond; |
| } |
| } |
| |
| /* Returns the initial condition of a given CHREC. */ |
| |
| tree |
| initial_condition (tree chrec) |
| { |
| if (automatically_generated_chrec_p (chrec)) |
| return chrec; |
| |
| if (TREE_CODE (chrec) == POLYNOMIAL_CHREC) |
| return initial_condition (CHREC_LEFT (chrec)); |
| else |
| return chrec; |
| } |
| |
| /* Returns a univariate function that represents the evolution in |
| LOOP_NUM. Mask the evolution of any other loop. */ |
| |
| tree |
| hide_evolution_in_other_loops_than_loop (tree chrec, |
| unsigned loop_num) |
| { |
| struct loop *loop = get_loop (cfun, loop_num), *chloop; |
| if (automatically_generated_chrec_p (chrec)) |
| return chrec; |
| |
| switch (TREE_CODE (chrec)) |
| { |
| case POLYNOMIAL_CHREC: |
| chloop = get_chrec_loop (chrec); |
| |
| if (chloop == loop) |
| return build_polynomial_chrec |
| (loop_num, |
| hide_evolution_in_other_loops_than_loop (CHREC_LEFT (chrec), |
| loop_num), |
| CHREC_RIGHT (chrec)); |
| |
| else if (flow_loop_nested_p (chloop, loop)) |
| /* There is no evolution in this loop. */ |
| return initial_condition (chrec); |
| |
| else if (flow_loop_nested_p (loop, chloop)) |
| return hide_evolution_in_other_loops_than_loop (CHREC_LEFT (chrec), |
| loop_num); |
| |
| else |
| return chrec_dont_know; |
| |
| default: |
| return chrec; |
| } |
| } |
| |
| /* Returns the evolution part of CHREC in LOOP_NUM when RIGHT is |
| true, otherwise returns the initial condition in LOOP_NUM. */ |
| |
| static tree |
| chrec_component_in_loop_num (tree chrec, |
| unsigned loop_num, |
| bool right) |
| { |
| tree component; |
| struct loop *loop = get_loop (cfun, loop_num), *chloop; |
| |
| if (automatically_generated_chrec_p (chrec)) |
| return chrec; |
| |
| switch (TREE_CODE (chrec)) |
| { |
| case POLYNOMIAL_CHREC: |
| chloop = get_chrec_loop (chrec); |
| |
| if (chloop == loop) |
| { |
| if (right) |
| component = CHREC_RIGHT (chrec); |
| else |
| component = CHREC_LEFT (chrec); |
| |
| if (TREE_CODE (CHREC_LEFT (chrec)) != POLYNOMIAL_CHREC |
| || CHREC_VARIABLE (CHREC_LEFT (chrec)) != CHREC_VARIABLE (chrec)) |
| return component; |
| |
| else |
| return build_polynomial_chrec |
| (loop_num, |
| chrec_component_in_loop_num (CHREC_LEFT (chrec), |
| loop_num, |
| right), |
| component); |
| } |
| |
| else if (flow_loop_nested_p (chloop, loop)) |
| /* There is no evolution part in this loop. */ |
| return NULL_TREE; |
| |
| else |
| { |
| gcc_assert (flow_loop_nested_p (loop, chloop)); |
| return chrec_component_in_loop_num (CHREC_LEFT (chrec), |
| loop_num, |
| right); |
| } |
| |
| default: |
| if (right) |
| return NULL_TREE; |
| else |
| return chrec; |
| } |
| } |
| |
| /* Returns the evolution part in LOOP_NUM. Example: the call |
| evolution_part_in_loop_num ({{0, +, 1}_1, +, 2}_1, 1) returns |
| {1, +, 2}_1 */ |
| |
| tree |
| evolution_part_in_loop_num (tree chrec, |
| unsigned loop_num) |
| { |
| return chrec_component_in_loop_num (chrec, loop_num, true); |
| } |
| |
| /* Returns the initial condition in LOOP_NUM. Example: the call |
| initial_condition_in_loop_num ({{0, +, 1}_1, +, 2}_2, 2) returns |
| {0, +, 1}_1 */ |
| |
| tree |
| initial_condition_in_loop_num (tree chrec, |
| unsigned loop_num) |
| { |
| return chrec_component_in_loop_num (chrec, loop_num, false); |
| } |
| |
| /* Set or reset the evolution of CHREC to NEW_EVOL in loop LOOP_NUM. |
| This function is essentially used for setting the evolution to |
| chrec_dont_know, for example after having determined that it is |
| impossible to say how many times a loop will execute. */ |
| |
| tree |
| reset_evolution_in_loop (unsigned loop_num, |
| tree chrec, |
| tree new_evol) |
| { |
| struct loop *loop = get_loop (cfun, loop_num); |
| |
| if (POINTER_TYPE_P (chrec_type (chrec))) |
| gcc_assert (ptrofftype_p (chrec_type (new_evol))); |
| else |
| gcc_assert (chrec_type (chrec) == chrec_type (new_evol)); |
| |
| if (TREE_CODE (chrec) == POLYNOMIAL_CHREC |
| && flow_loop_nested_p (loop, get_chrec_loop (chrec))) |
| { |
| tree left = reset_evolution_in_loop (loop_num, CHREC_LEFT (chrec), |
| new_evol); |
| tree right = reset_evolution_in_loop (loop_num, CHREC_RIGHT (chrec), |
| new_evol); |
| return build_polynomial_chrec (CHREC_VARIABLE (chrec), left, right); |
| } |
| |
| while (TREE_CODE (chrec) == POLYNOMIAL_CHREC |
| && CHREC_VARIABLE (chrec) == loop_num) |
| chrec = CHREC_LEFT (chrec); |
| |
| return build_polynomial_chrec (loop_num, chrec, new_evol); |
| } |
| |
| /* Merges two evolution functions that were found by following two |
| alternate paths of a conditional expression. */ |
| |
| tree |
| chrec_merge (tree chrec1, |
| tree chrec2) |
| { |
| if (chrec1 == chrec_dont_know |
| || chrec2 == chrec_dont_know) |
| return chrec_dont_know; |
| |
| if (chrec1 == chrec_known |
| || chrec2 == chrec_known) |
| return chrec_known; |
| |
| if (chrec1 == chrec_not_analyzed_yet) |
| return chrec2; |
| if (chrec2 == chrec_not_analyzed_yet) |
| return chrec1; |
| |
| if (eq_evolutions_p (chrec1, chrec2)) |
| return chrec1; |
| |
| return chrec_dont_know; |
| } |
| |
| |
| |
| /* Observers. */ |
| |
| /* Helper function for is_multivariate_chrec. */ |
| |
| static bool |
| is_multivariate_chrec_rec (const_tree chrec, unsigned int rec_var) |
| { |
| if (chrec == NULL_TREE) |
| return false; |
| |
| if (TREE_CODE (chrec) == POLYNOMIAL_CHREC) |
| { |
| if (CHREC_VARIABLE (chrec) != rec_var) |
| return true; |
| else |
| return (is_multivariate_chrec_rec (CHREC_LEFT (chrec), rec_var) |
| || is_multivariate_chrec_rec (CHREC_RIGHT (chrec), rec_var)); |
| } |
| else |
| return false; |
| } |
| |
| /* Determine whether the given chrec is multivariate or not. */ |
| |
| bool |
| is_multivariate_chrec (const_tree chrec) |
| { |
| if (chrec == NULL_TREE) |
| return false; |
| |
| if (TREE_CODE (chrec) == POLYNOMIAL_CHREC) |
| return (is_multivariate_chrec_rec (CHREC_LEFT (chrec), |
| CHREC_VARIABLE (chrec)) |
| || is_multivariate_chrec_rec (CHREC_RIGHT (chrec), |
| CHREC_VARIABLE (chrec))); |
| else |
| return false; |
| } |
| |
| /* Determines whether the chrec contains symbolic names or not. */ |
| |
| bool |
| chrec_contains_symbols (const_tree chrec) |
| { |
| int i, n; |
| |
| if (chrec == NULL_TREE) |
| return false; |
| |
| if (TREE_CODE (chrec) == SSA_NAME |
| || VAR_P (chrec) |
| || TREE_CODE (chrec) == PARM_DECL |
| || TREE_CODE (chrec) == FUNCTION_DECL |
| || TREE_CODE (chrec) == LABEL_DECL |
| || TREE_CODE (chrec) == RESULT_DECL |
| || TREE_CODE (chrec) == FIELD_DECL) |
| return true; |
| |
| n = TREE_OPERAND_LENGTH (chrec); |
| for (i = 0; i < n; i++) |
| if (chrec_contains_symbols (TREE_OPERAND (chrec, i))) |
| return true; |
| return false; |
| } |
| |
| /* Determines whether the chrec contains undetermined coefficients. */ |
| |
| bool |
| chrec_contains_undetermined (const_tree chrec) |
| { |
| int i, n; |
| |
| if (chrec == chrec_dont_know) |
| return true; |
| |
| if (chrec == NULL_TREE) |
| return false; |
| |
| n = TREE_OPERAND_LENGTH (chrec); |
| for (i = 0; i < n; i++) |
| if (chrec_contains_undetermined (TREE_OPERAND (chrec, i))) |
| return true; |
| return false; |
| } |
| |
| /* Determines whether the tree EXPR contains chrecs, and increment |
| SIZE if it is not a NULL pointer by an estimation of the depth of |
| the tree. */ |
| |
| bool |
| tree_contains_chrecs (const_tree expr, int *size) |
| { |
| int i, n; |
| |
| if (expr == NULL_TREE) |
| return false; |
| |
| if (size) |
| (*size)++; |
| |
| if (tree_is_chrec (expr)) |
| return true; |
| |
| n = TREE_OPERAND_LENGTH (expr); |
| for (i = 0; i < n; i++) |
| if (tree_contains_chrecs (TREE_OPERAND (expr, i), size)) |
| return true; |
| return false; |
| } |
| |
| /* Recursive helper function. */ |
| |
| static bool |
| evolution_function_is_invariant_rec_p (tree chrec, int loopnum) |
| { |
| if (evolution_function_is_constant_p (chrec)) |
| return true; |
| |
| if (TREE_CODE (chrec) == SSA_NAME |
| && (loopnum == 0 |
| || expr_invariant_in_loop_p (get_loop (cfun, loopnum), chrec))) |
| return true; |
| |
| if (TREE_CODE (chrec) == POLYNOMIAL_CHREC) |
| { |
| if (CHREC_VARIABLE (chrec) == (unsigned) loopnum |
| || flow_loop_nested_p (get_loop (cfun, loopnum), |
| get_chrec_loop (chrec)) |
| || !evolution_function_is_invariant_rec_p (CHREC_RIGHT (chrec), |
| loopnum) |
| || !evolution_function_is_invariant_rec_p (CHREC_LEFT (chrec), |
| loopnum)) |
| return false; |
| return true; |
| } |
| |
| switch (TREE_OPERAND_LENGTH (chrec)) |
| { |
| case 2: |
| if (!evolution_function_is_invariant_rec_p (TREE_OPERAND (chrec, 1), |
| loopnum)) |
| return false; |
| /* FALLTHRU */ |
| |
| case 1: |
| if (!evolution_function_is_invariant_rec_p (TREE_OPERAND (chrec, 0), |
| loopnum)) |
| return false; |
| return true; |
| |
| default: |
| return false; |
| } |
| |
| return false; |
| } |
| |
| /* Return true if CHREC is invariant in loop LOOPNUM, false otherwise. */ |
| |
| bool |
| evolution_function_is_invariant_p (tree chrec, int loopnum) |
| { |
| return evolution_function_is_invariant_rec_p (chrec, loopnum); |
| } |
| |
| /* Determine whether the given tree is an affine multivariate |
| evolution. */ |
| |
| bool |
| evolution_function_is_affine_multivariate_p (const_tree chrec, int loopnum) |
| { |
| if (chrec == NULL_TREE) |
| return false; |
| |
| switch (TREE_CODE (chrec)) |
| { |
| case POLYNOMIAL_CHREC: |
| if (evolution_function_is_invariant_rec_p (CHREC_LEFT (chrec), loopnum)) |
| { |
| if (evolution_function_is_invariant_rec_p (CHREC_RIGHT (chrec), loopnum)) |
| return true; |
| else |
| { |
| if (TREE_CODE (CHREC_RIGHT (chrec)) == POLYNOMIAL_CHREC |
| && CHREC_VARIABLE (CHREC_RIGHT (chrec)) |
| != CHREC_VARIABLE (chrec) |
| && evolution_function_is_affine_multivariate_p |
| (CHREC_RIGHT (chrec), loopnum)) |
| return true; |
| else |
| return false; |
| } |
| } |
| else |
| { |
| if (evolution_function_is_invariant_rec_p (CHREC_RIGHT (chrec), loopnum) |
| && TREE_CODE (CHREC_LEFT (chrec)) == POLYNOMIAL_CHREC |
| && CHREC_VARIABLE (CHREC_LEFT (chrec)) != CHREC_VARIABLE (chrec) |
| && evolution_function_is_affine_multivariate_p |
| (CHREC_LEFT (chrec), loopnum)) |
| return true; |
| else |
| return false; |
| } |
| |
| default: |
| return false; |
| } |
| } |
| |
| /* Determine whether the given tree is a function in zero or one |
| variables. */ |
| |
| bool |
| evolution_function_is_univariate_p (const_tree chrec) |
| { |
| if (chrec == NULL_TREE) |
| return true; |
| |
| switch (TREE_CODE (chrec)) |
| { |
| case POLYNOMIAL_CHREC: |
| switch (TREE_CODE (CHREC_LEFT (chrec))) |
| { |
| case POLYNOMIAL_CHREC: |
| if (CHREC_VARIABLE (chrec) != CHREC_VARIABLE (CHREC_LEFT (chrec))) |
| return false; |
| if (!evolution_function_is_univariate_p (CHREC_LEFT (chrec))) |
| return false; |
| break; |
| |
| default: |
| if (tree_contains_chrecs (CHREC_LEFT (chrec), NULL)) |
| return false; |
| break; |
| } |
| |
| switch (TREE_CODE (CHREC_RIGHT (chrec))) |
| { |
| case POLYNOMIAL_CHREC: |
| if (CHREC_VARIABLE (chrec) != CHREC_VARIABLE (CHREC_RIGHT (chrec))) |
| return false; |
| if (!evolution_function_is_univariate_p (CHREC_RIGHT (chrec))) |
| return false; |
| break; |
| |
| default: |
| if (tree_contains_chrecs (CHREC_RIGHT (chrec), NULL)) |
| return false; |
| break; |
| } |
| |
| default: |
| return true; |
| } |
| } |
| |
| /* Returns the number of variables of CHREC. Example: the call |
| nb_vars_in_chrec ({{0, +, 1}_5, +, 2}_6) returns 2. */ |
| |
| unsigned |
| nb_vars_in_chrec (tree chrec) |
| { |
| if (chrec == NULL_TREE) |
| return 0; |
| |
| switch (TREE_CODE (chrec)) |
| { |
| case POLYNOMIAL_CHREC: |
| return 1 + nb_vars_in_chrec |
| (initial_condition_in_loop_num (chrec, CHREC_VARIABLE (chrec))); |
| |
| default: |
| return 0; |
| } |
| } |
| |
| /* Converts BASE and STEP of affine scev to TYPE. LOOP is the loop whose iv |
| the scev corresponds to. AT_STMT is the statement at that the scev is |
| evaluated. USE_OVERFLOW_SEMANTICS is true if this function should assume |
| that the rules for overflow of the given language apply (e.g., that signed |
| arithmetics in C does not overflow) -- i.e., to use them to avoid |
| unnecessary tests, but also to enforce that the result follows them. |
| FROM is the source variable converted if it's not NULL. Returns true if |
| the conversion succeeded, false otherwise. */ |
| |
| bool |
| convert_affine_scev (struct loop *loop, tree type, |
| tree *base, tree *step, gimple *at_stmt, |
| bool use_overflow_semantics, tree from) |
| { |
| tree ct = TREE_TYPE (*step); |
| bool enforce_overflow_semantics; |
| bool must_check_src_overflow, must_check_rslt_overflow; |
| tree new_base, new_step; |
| tree step_type = POINTER_TYPE_P (type) ? sizetype : type; |
| |
| /* In general, |
| (TYPE) (BASE + STEP * i) = (TYPE) BASE + (TYPE -- sign extend) STEP * i, |
| but we must check some assumptions. |
| |
| 1) If [BASE, +, STEP] wraps, the equation is not valid when precision |
| of CT is smaller than the precision of TYPE. For example, when we |
| cast unsigned char [254, +, 1] to unsigned, the values on left side |
| are 254, 255, 0, 1, ..., but those on the right side are |
| 254, 255, 256, 257, ... |
| 2) In case that we must also preserve the fact that signed ivs do not |
| overflow, we must additionally check that the new iv does not wrap. |
| For example, unsigned char [125, +, 1] casted to signed char could |
| become a wrapping variable with values 125, 126, 127, -128, -127, ..., |
| which would confuse optimizers that assume that this does not |
| happen. */ |
| must_check_src_overflow = TYPE_PRECISION (ct) < TYPE_PRECISION (type); |
| |
| enforce_overflow_semantics = (use_overflow_semantics |
| && nowrap_type_p (type)); |
| if (enforce_overflow_semantics) |
| { |
| /* We can avoid checking whether the result overflows in the following |
| cases: |
| |
| -- must_check_src_overflow is true, and the range of TYPE is superset |
| of the range of CT -- i.e., in all cases except if CT signed and |
| TYPE unsigned. |
| -- both CT and TYPE have the same precision and signedness, and we |
| verify instead that the source does not overflow (this may be |
| easier than verifying it for the result, as we may use the |
| information about the semantics of overflow in CT). */ |
| if (must_check_src_overflow) |
| { |
| if (TYPE_UNSIGNED (type) && !TYPE_UNSIGNED (ct)) |
| must_check_rslt_overflow = true; |
| else |
| must_check_rslt_overflow = false; |
| } |
| else if (TYPE_UNSIGNED (ct) == TYPE_UNSIGNED (type) |
| && TYPE_PRECISION (ct) == TYPE_PRECISION (type)) |
| { |
| must_check_rslt_overflow = false; |
| must_check_src_overflow = true; |
| } |
| else |
| must_check_rslt_overflow = true; |
| } |
| else |
| must_check_rslt_overflow = false; |
| |
| if (must_check_src_overflow |
| && scev_probably_wraps_p (from, *base, *step, at_stmt, loop, |
| use_overflow_semantics)) |
| return false; |
| |
| new_base = chrec_convert (type, *base, at_stmt, use_overflow_semantics); |
| /* The step must be sign extended, regardless of the signedness |
| of CT and TYPE. This only needs to be handled specially when |
| CT is unsigned -- to avoid e.g. unsigned char [100, +, 255] |
| (with values 100, 99, 98, ...) from becoming signed or unsigned |
| [100, +, 255] with values 100, 355, ...; the sign-extension is |
| performed by default when CT is signed. */ |
| new_step = *step; |
| if (TYPE_PRECISION (step_type) > TYPE_PRECISION (ct) && TYPE_UNSIGNED (ct)) |
| { |
| tree signed_ct = build_nonstandard_integer_type (TYPE_PRECISION (ct), 0); |
| new_step = chrec_convert (signed_ct, new_step, at_stmt, |
| use_overflow_semantics); |
| } |
| new_step = chrec_convert (step_type, new_step, at_stmt, |
| use_overflow_semantics); |
| |
| if (automatically_generated_chrec_p (new_base) |
| || automatically_generated_chrec_p (new_step)) |
| return false; |
| |
| if (must_check_rslt_overflow |
| /* Note that in this case we cannot use the fact that signed variables |
| do not overflow, as this is what we are verifying for the new iv. */ |
| && scev_probably_wraps_p (NULL_TREE, new_base, new_step, |
| at_stmt, loop, false)) |
| return false; |
| |
| *base = new_base; |
| *step = new_step; |
| return true; |
| } |
| |
| |
| /* Convert CHREC for the right hand side of a CHREC. |
| The increment for a pointer type is always sizetype. */ |
| |
| tree |
| chrec_convert_rhs (tree type, tree chrec, gimple *at_stmt) |
| { |
| if (POINTER_TYPE_P (type)) |
| type = sizetype; |
| |
| return chrec_convert (type, chrec, at_stmt); |
| } |
| |
| /* Convert CHREC to TYPE. When the analyzer knows the context in |
| which the CHREC is built, it sets AT_STMT to the statement that |
| contains the definition of the analyzed variable, otherwise the |
| conversion is less accurate: the information is used for |
| determining a more accurate estimation of the number of iterations. |
| By default AT_STMT could be safely set to NULL_TREE. |
| |
| USE_OVERFLOW_SEMANTICS is true if this function should assume that |
| the rules for overflow of the given language apply (e.g., that signed |
| arithmetics in C does not overflow) -- i.e., to use them to avoid |
| unnecessary tests, but also to enforce that the result follows them. |
| |
| FROM is the source variable converted if it's not NULL. */ |
| |
| static tree |
| chrec_convert_1 (tree type, tree chrec, gimple *at_stmt, |
| bool use_overflow_semantics, tree from) |
| { |
| tree ct, res; |
| tree base, step; |
| struct loop *loop; |
| |
| if (automatically_generated_chrec_p (chrec)) |
| return chrec; |
| |
| ct = chrec_type (chrec); |
| if (useless_type_conversion_p (type, ct)) |
| return chrec; |
| |
| if (!evolution_function_is_affine_p (chrec)) |
| goto keep_cast; |
| |
| loop = get_chrec_loop (chrec); |
| base = CHREC_LEFT (chrec); |
| step = CHREC_RIGHT (chrec); |
| |
| if (convert_affine_scev (loop, type, &base, &step, at_stmt, |
| use_overflow_semantics, from)) |
| return build_polynomial_chrec (loop->num, base, step); |
| |
| /* If we cannot propagate the cast inside the chrec, just keep the cast. */ |
| keep_cast: |
| /* Fold will not canonicalize (long)(i - 1) to (long)i - 1 because that |
| may be more expensive. We do want to perform this optimization here |
| though for canonicalization reasons. */ |
| if (use_overflow_semantics |
| && (TREE_CODE (chrec) == PLUS_EXPR |
| || TREE_CODE (chrec) == MINUS_EXPR) |
| && TREE_CODE (type) == INTEGER_TYPE |
| && TREE_CODE (ct) == INTEGER_TYPE |
| && TYPE_PRECISION (type) > TYPE_PRECISION (ct) |
| && TYPE_OVERFLOW_UNDEFINED (ct)) |
| res = fold_build2 (TREE_CODE (chrec), type, |
| fold_convert (type, TREE_OPERAND (chrec, 0)), |
| fold_convert (type, TREE_OPERAND (chrec, 1))); |
| /* Similar perform the trick that (signed char)((int)x + 2) can be |
| narrowed to (signed char)((unsigned char)x + 2). */ |
| else if (use_overflow_semantics |
| && TREE_CODE (chrec) == POLYNOMIAL_CHREC |
| && TREE_CODE (ct) == INTEGER_TYPE |
| && TREE_CODE (type) == INTEGER_TYPE |
| && TYPE_OVERFLOW_UNDEFINED (type) |
| && TYPE_PRECISION (type) < TYPE_PRECISION (ct)) |
| { |
| tree utype = unsigned_type_for (type); |
| res = build_polynomial_chrec (CHREC_VARIABLE (chrec), |
| fold_convert (utype, |
| CHREC_LEFT (chrec)), |
| fold_convert (utype, |
| CHREC_RIGHT (chrec))); |
| res = chrec_convert_1 (type, res, at_stmt, use_overflow_semantics, from); |
| } |
| else |
| res = fold_convert (type, chrec); |
| |
| /* Don't propagate overflows. */ |
| if (CONSTANT_CLASS_P (res)) |
| TREE_OVERFLOW (res) = 0; |
| |
| /* But reject constants that don't fit in their type after conversion. |
| This can happen if TYPE_MIN_VALUE or TYPE_MAX_VALUE are not the |
| natural values associated with TYPE_PRECISION and TYPE_UNSIGNED, |
| and can cause problems later when computing niters of loops. Note |
| that we don't do the check before converting because we don't want |
| to reject conversions of negative chrecs to unsigned types. */ |
| if (TREE_CODE (res) == INTEGER_CST |
| && TREE_CODE (type) == INTEGER_TYPE |
| && !int_fits_type_p (res, type)) |
| res = chrec_dont_know; |
| |
| return res; |
| } |
| |
| /* Convert CHREC to TYPE. When the analyzer knows the context in |
| which the CHREC is built, it sets AT_STMT to the statement that |
| contains the definition of the analyzed variable, otherwise the |
| conversion is less accurate: the information is used for |
| determining a more accurate estimation of the number of iterations. |
| By default AT_STMT could be safely set to NULL_TREE. |
| |
| The following rule is always true: TREE_TYPE (chrec) == |
| TREE_TYPE (CHREC_LEFT (chrec)) == TREE_TYPE (CHREC_RIGHT (chrec)). |
| An example of what could happen when adding two chrecs and the type |
| of the CHREC_RIGHT is different than CHREC_LEFT is: |
| |
| {(uint) 0, +, (uchar) 10} + |
| {(uint) 0, +, (uchar) 250} |
| |
| that would produce a wrong result if CHREC_RIGHT is not (uint): |
| |
| {(uint) 0, +, (uchar) 4} |
| |
| instead of |
| |
| {(uint) 0, +, (uint) 260} |
| |
| USE_OVERFLOW_SEMANTICS is true if this function should assume that |
| the rules for overflow of the given language apply (e.g., that signed |
| arithmetics in C does not overflow) -- i.e., to use them to avoid |
| unnecessary tests, but also to enforce that the result follows them. |
| |
| FROM is the source variable converted if it's not NULL. */ |
| |
| tree |
| chrec_convert (tree type, tree chrec, gimple *at_stmt, |
| bool use_overflow_semantics, tree from) |
| { |
| return chrec_convert_1 (type, chrec, at_stmt, use_overflow_semantics, from); |
| } |
| |
| /* Convert CHREC to TYPE, without regard to signed overflows. Returns the new |
| chrec if something else than what chrec_convert would do happens, NULL_TREE |
| otherwise. This function set TRUE to variable pointed by FOLD_CONVERSIONS |
| if the result chrec may overflow. */ |
| |
| tree |
| chrec_convert_aggressive (tree type, tree chrec, bool *fold_conversions) |
| { |
| tree inner_type, left, right, lc, rc, rtype; |
| |
| gcc_assert (fold_conversions != NULL); |
| |
| if (automatically_generated_chrec_p (chrec) |
| || TREE_CODE (chrec) != POLYNOMIAL_CHREC) |
| return NULL_TREE; |
| |
| inner_type = TREE_TYPE (chrec); |
| if (TYPE_PRECISION (type) > TYPE_PRECISION (inner_type)) |
| return NULL_TREE; |
| |
| if (useless_type_conversion_p (type, inner_type)) |
| return NULL_TREE; |
| |
| if (!*fold_conversions && evolution_function_is_affine_p (chrec)) |
| { |
| tree base, step; |
| struct loop *loop; |
| |
| loop = get_chrec_loop (chrec); |
| base = CHREC_LEFT (chrec); |
| step = CHREC_RIGHT (chrec); |
| if (convert_affine_scev (loop, type, &base, &step, NULL, true)) |
| return build_polynomial_chrec (loop->num, base, step); |
| } |
| rtype = POINTER_TYPE_P (type) ? sizetype : type; |
| |
| left = CHREC_LEFT (chrec); |
| right = CHREC_RIGHT (chrec); |
| lc = chrec_convert_aggressive (type, left, fold_conversions); |
| if (!lc) |
| lc = chrec_convert (type, left, NULL); |
| rc = chrec_convert_aggressive (rtype, right, fold_conversions); |
| if (!rc) |
| rc = chrec_convert (rtype, right, NULL); |
| |
| *fold_conversions = true; |
| |
| return build_polynomial_chrec (CHREC_VARIABLE (chrec), lc, rc); |
| } |
| |
| /* Returns true when CHREC0 == CHREC1. */ |
| |
| bool |
| eq_evolutions_p (const_tree chrec0, const_tree chrec1) |
| { |
| if (chrec0 == NULL_TREE |
| || chrec1 == NULL_TREE |
| || TREE_CODE (chrec0) != TREE_CODE (chrec1)) |
| return false; |
| |
| if (chrec0 == chrec1) |
| return true; |
| |
| if (! types_compatible_p (TREE_TYPE (chrec0), TREE_TYPE (chrec1))) |
| return false; |
| |
| switch (TREE_CODE (chrec0)) |
| { |
| case POLYNOMIAL_CHREC: |
| return (CHREC_VARIABLE (chrec0) == CHREC_VARIABLE (chrec1) |
| && eq_evolutions_p (CHREC_LEFT (chrec0), CHREC_LEFT (chrec1)) |
| && eq_evolutions_p (CHREC_RIGHT (chrec0), CHREC_RIGHT (chrec1))); |
| |
| case PLUS_EXPR: |
| case MULT_EXPR: |
| case MINUS_EXPR: |
| case POINTER_PLUS_EXPR: |
| return eq_evolutions_p (TREE_OPERAND (chrec0, 0), |
| TREE_OPERAND (chrec1, 0)) |
| && eq_evolutions_p (TREE_OPERAND (chrec0, 1), |
| TREE_OPERAND (chrec1, 1)); |
| |
| CASE_CONVERT: |
| return eq_evolutions_p (TREE_OPERAND (chrec0, 0), |
| TREE_OPERAND (chrec1, 0)); |
| |
| default: |
| return operand_equal_p (chrec0, chrec1, 0); |
| } |
| } |
| |
| /* Returns EV_GROWS if CHREC grows (assuming that it does not overflow), |
| EV_DECREASES if it decreases, and EV_UNKNOWN if we cannot determine |
| which of these cases happens. */ |
| |
| enum ev_direction |
| scev_direction (const_tree chrec) |
| { |
| const_tree step; |
| |
| if (!evolution_function_is_affine_p (chrec)) |
| return EV_DIR_UNKNOWN; |
| |
| step = CHREC_RIGHT (chrec); |
| if (TREE_CODE (step) != INTEGER_CST) |
| return EV_DIR_UNKNOWN; |
| |
| if (tree_int_cst_sign_bit (step)) |
| return EV_DIR_DECREASES; |
| else |
| return EV_DIR_GROWS; |
| } |
| |
| /* Iterates over all the components of SCEV, and calls CBCK. */ |
| |
| void |
| for_each_scev_op (tree *scev, bool (*cbck) (tree *, void *), void *data) |
| { |
| switch (TREE_CODE_LENGTH (TREE_CODE (*scev))) |
| { |
| case 3: |
| for_each_scev_op (&TREE_OPERAND (*scev, 2), cbck, data); |
| /* FALLTHRU */ |
| |
| case 2: |
| for_each_scev_op (&TREE_OPERAND (*scev, 1), cbck, data); |
| /* FALLTHRU */ |
| |
| case 1: |
| for_each_scev_op (&TREE_OPERAND (*scev, 0), cbck, data); |
| /* FALLTHRU */ |
| |
| default: |
| cbck (scev, data); |
| break; |
| } |
| } |
| |
| /* Returns true when the operation can be part of a linear |
| expression. */ |
| |
| static inline bool |
| operator_is_linear (tree scev) |
| { |
| switch (TREE_CODE (scev)) |
| { |
| case INTEGER_CST: |
| case POLYNOMIAL_CHREC: |
| case PLUS_EXPR: |
| case POINTER_PLUS_EXPR: |
| case MULT_EXPR: |
| case MINUS_EXPR: |
| case NEGATE_EXPR: |
| case SSA_NAME: |
| case NON_LVALUE_EXPR: |
| case BIT_NOT_EXPR: |
| CASE_CONVERT: |
| return true; |
| |
| default: |
| return false; |
| } |
| } |
| |
| /* Return true when SCEV is a linear expression. Linear expressions |
| can contain additions, substractions and multiplications. |
| Multiplications are restricted to constant scaling: "cst * x". */ |
| |
| bool |
| scev_is_linear_expression (tree scev) |
| { |
| if (evolution_function_is_constant_p (scev)) |
| return true; |
| |
| if (scev == NULL |
| || !operator_is_linear (scev)) |
| return false; |
| |
| if (TREE_CODE (scev) == MULT_EXPR) |
| return !(tree_contains_chrecs (TREE_OPERAND (scev, 0), NULL) |
| && tree_contains_chrecs (TREE_OPERAND (scev, 1), NULL)); |
| |
| if (TREE_CODE (scev) == POLYNOMIAL_CHREC |
| && !evolution_function_is_affine_multivariate_p (scev, CHREC_VARIABLE (scev))) |
| return false; |
| |
| switch (TREE_CODE_LENGTH (TREE_CODE (scev))) |
| { |
| case 3: |
| return scev_is_linear_expression (TREE_OPERAND (scev, 0)) |
| && scev_is_linear_expression (TREE_OPERAND (scev, 1)) |
| && scev_is_linear_expression (TREE_OPERAND (scev, 2)); |
| |
| case 2: |
| return scev_is_linear_expression (TREE_OPERAND (scev, 0)) |
| && scev_is_linear_expression (TREE_OPERAND (scev, 1)); |
| |
| case 1: |
| return scev_is_linear_expression (TREE_OPERAND (scev, 0)); |
| |
| case 0: |
| return true; |
| |
| default: |
| return false; |
| } |
| } |
| |
| /* Determines whether the expression CHREC contains only interger consts |
| in the right parts. */ |
| |
| bool |
| evolution_function_right_is_integer_cst (const_tree chrec) |
| { |
| if (chrec == NULL_TREE) |
| return false; |
| |
| switch (TREE_CODE (chrec)) |
| { |
| case INTEGER_CST: |
| return true; |
| |
| case POLYNOMIAL_CHREC: |
| return TREE_CODE (CHREC_RIGHT (chrec)) == INTEGER_CST |
| && (TREE_CODE (CHREC_LEFT (chrec)) != POLYNOMIAL_CHREC |
| || evolution_function_right_is_integer_cst (CHREC_LEFT (chrec))); |
| |
| CASE_CONVERT: |
| return evolution_function_right_is_integer_cst (TREE_OPERAND (chrec, 0)); |
| |
| default: |
| return false; |
| } |
| } |