Re: [PATCH] Get rid of ? true : false and simplify ? false : true

On Fri, Jul 31, 2026 at 6:59 AM Jakub Jelinek <[email protected]> wrote:
>
> Hi!
>
> Last night I've noticed in match.pd various places like
> cmp == EQ_EXPR ? true : false
> and
> cmp == EQ_EXPR ? false : true
> I don't think that is useful, neither for readers nor for code formatting.
> Sure, x ? true : false is not always equivalent to just x, but if it is
> passed to a bool argument or sets a bool variable or if x is actually
> a comparison in C++, it is exactly the same.
> I think using just cmp == EQ_EXPR and cmp != EQ_EXPR is better.
>
> So far lightly tested, ok for trunk if it passes full bootstrap/regtest?
>
> 2026-07-31  Jakub Jelinek  <[email protected]>
>
>         * ipa-polymorphic-call.cc (csftc_abort_walking_p): Remove useless
>         "? true : false".
>         * tree-ssa-loop-im.cc (ref_indep_loop_p): Likewise.
>         * match.pd (X ==/!= !X is false/true): Replace "? false : true"
>         with negation of the condition.
>         (((C << x) & D) != 0): Likewise.
>         (fold_sign_changed_comparison and fold_widened_comparison): Likewise.
>         Remove useless "? true : false".
>         (if the second operand is NaN, the result is constant): Replace
>         "? false : true" with negation of the condition.
>         (__builtin_ctz (x) >= C -> (x & ((1 << C) - 1)) == 0): Likewise.
>         Remove useless "? true : false".
>         (__builtin_ctz (x) == C -> (x & ((1 << (C + 1)) - 1)) == (1 << C)):
>         Replace "? false : true" with negation of the condition.
>         (__builtin_ffs (X) == 0 -> X == 0): Remove useless "? true : false".
>         (__builtin_ffs (X) > 6 -> X != 0 && (X & 63) == 0): Likewise.
>         Replace "? false : true" with negation of the condition.
>         * gimple-pretty-print.cc (dump_phi_nodes):
>         Use (flags & TDF_GIMPLE) == 0 instead
>         of (flags & TDF_GIMPLE) ? false : true.
> gcc/fortran/
>         * expr.cc (gfc_check_init_expr): Remove useless "? true : false".
>         (gfc_expr_check_typed): Replace "? false : true" with negation of the
>         condition.
>         * parse.cc (gfc_find_state): Likewise.
>         * resolve.cc (impure_stmt_fcn): Likewise.
>         * arith.cc (gfc_check_character_range): Remove useless
>         "? true : false".
>         * array.cc (is_constant_element): Likewise.
>         * decl.cc (gfc_verify_c_interop): Likewise.
>         * interface.cc (gfc_check_dummy_characteristics): Likewise.
>         * io.cc (check_open_constraints): Likewise.
>         (check_close_constraints): Likewise.
>         (check_io_constraints): Likewise.
> gcc/jit/
>         * jit-recording.cc (recording::context::set_bool_option): Remove
>         useless "? true : false".

Ok though ...

>
> --- gcc/ipa-polymorphic-call.cc.jj      2026-05-30 17:45:09.439109090 +0200
> +++ gcc/ipa-polymorphic-call.cc 2026-07-31 15:17:30.309767738 +0200
> @@ -1405,7 +1405,7 @@ static inline bool
>  csftc_abort_walking_p (unsigned speculative)
>  {
>    unsigned max = param_max_speculative_devirt_maydefs;
> -  return speculative > max ? true : false;
> +  return speculative > max;
>  }
>
>  /* Callback of walk_aliased_vdefs and a helper function for
> --- gcc/tree-ssa-loop-im.cc.jj  2026-06-25 10:03:50.887435500 +0200
> +++ gcc/tree-ssa-loop-im.cc     2026-07-31 15:17:57.214437056 +0200
> @@ -3257,7 +3257,7 @@ ref_indep_loop_p (class loop *loop, im_m
>        /* tri-state, { unknown, independent, dependent }  */
>        dep_state state = query_loop_dependence (loop, ref, kind);
>        if (state != dep_unknown)
> -       return state == dep_independent ? true : false;
> +       return state == dep_independent;
>
>        class loop *inner = loop->inner;
>        while (inner)
> --- gcc/match.pd.jj     2026-07-31 09:11:01.089161684 +0200
> +++ gcc/match.pd        2026-07-31 15:19:53.051013328 +0200
> @@ -2522,7 +2522,7 @@ (define_operator_list SYNC_FETCH_AND_AND
>  (for op (bit_ior bit_xor eq ne)
>   (simplify
>    (op:c truth_valued_p@0 (logical_inverted_value @0))
> -  { constant_boolean_node (op == EQ_EXPR ? false : true, type); }))
> +  { constant_boolean_node (op != EQ_EXPR, type); }))
>
>  /* ~~x -> x */
>  (simplify
> @@ -5289,7 +5289,7 @@ (define_operator_list SYNC_FETCH_AND_AND
>             than D.  See PR126476.  */
>          || !wi::fits_to_tree_p (wi::shwi (c1 - c2, HOST_BITS_PER_INT),
>                                  TREE_TYPE (@0)))
> -     { constant_boolean_node (cmp == NE_EXPR ? false : true, type); }
> +     { constant_boolean_node (cmp != NE_EXPR, type); }
>       (icmp @0 { build_int_cst (TREE_TYPE (@0), c1 - c2); }))))
>   (simplify
>    (cmp (bit_and (rshift integer_pow2p@1 @0) integer_pow2p@2) integer_zerop)
> @@ -5299,7 +5299,7 @@ (define_operator_list SYNC_FETCH_AND_AND
>       (if (c1 > c2
>           || !wi::fits_to_tree_p (wi::shwi (c2 - c1, HOST_BITS_PER_INT),
>                                   TREE_TYPE (@0)))
> -      { constant_boolean_node (cmp == NE_EXPR ? false : true, type); }
> +      { constant_boolean_node (cmp != NE_EXPR, type); }
>        (icmp @0 { build_int_cst (TREE_TYPE (@0), c2 - c1); }))))))
>
>  /* (CST1 << A) == CST2 -> A == ctz (CST2) - ctz (CST1)
> @@ -8104,11 +8104,11 @@ (define_operator_list SYNC_FETCH_AND_AND
>         }
>         (if (above || below)
>          (if (cmp == EQ_EXPR || cmp == NE_EXPR)
> -         { constant_boolean_node (cmp == EQ_EXPR ? false : true, type); }
> +         { constant_boolean_node (cmp != EQ_EXPR, type); }
>           (if (cmp == LT_EXPR || cmp == LE_EXPR)
> -          { constant_boolean_node (above ? true : false, type); }
> +          { constant_boolean_node (above, type); }
>            (if (cmp == GT_EXPR || cmp == GE_EXPR)
> -           { constant_boolean_node (above ? false : true, type); })))))))
> +           { constant_boolean_node (!above, type); })))))))
>
>      /* For eq/ne with narrowing conversion:
>         (T)(X) == (T)(Y) -> (T)(X ^ Y) == 0  */
> @@ -8584,8 +8584,8 @@ (define_operator_list SYNC_FETCH_AND_AND
>    (cmp @0 REAL_CST@1)
>    (if (REAL_VALUE_ISNAN (TREE_REAL_CST (@1))
>         && (cmp != LTGT_EXPR || ! flag_trapping_math))
> -   { constant_boolean_node (cmp == ORDERED_EXPR || cmp == LTGT_EXPR
> -                           ? false : true, type); })))
> +   { constant_boolean_node (cmp != ORDERED_EXPR && cmp != LTGT_EXPR,
> +                           type); })))
>
>  /* Fold UNORDERED if either operand must be NaN, or neither can be.  */
>  (simplify
> @@ -10535,9 +10535,9 @@ (define_operator_list SYNC_FETCH_AND_AND
>           }
>       (if (ok && prec <= MAX_FIXED_MODE_SIZE)
>        (if (val <= 0)
> -       { constant_boolean_node (cmp == EQ_EXPR ? true : false, type); }
> +       { constant_boolean_node (cmp == EQ_EXPR, type); }
>         (if (val >= prec)
> -       { constant_boolean_node (cmp == EQ_EXPR ? false : true, type); }
> +       { constant_boolean_node (cmp != EQ_EXPR, type); }
>         (cmp (bit_and @0 { wide_int_to_tree (type0,
>                                              wi::mask (val, false, prec)); })
>              { build_zero_cst (type0); })))))))
> @@ -10557,7 +10557,7 @@ (define_operator_list SYNC_FETCH_AND_AND
>           }
>       (if (ok && prec <= MAX_FIXED_MODE_SIZE)
>        (if (tree_int_cst_sgn (@1) < 0 || wi::to_widest (@1) >= prec)
> -       { constant_boolean_node (op == EQ_EXPR ? false : true, type); }
> +       { constant_boolean_node (op != EQ_EXPR, type); }
>         (op (bit_and @0 { wide_int_to_tree (type0,
>                                            wi::mask (tree_to_uhwi (@1) + 1,
>                                                      false, prec)); })
> @@ -10593,10 +10593,10 @@ (define_operator_list SYNC_FETCH_AND_AND
>           }
>       (if (val <= 0)
>        (if (ok && zero_val >= val)
> -       { constant_boolean_node (cmp == EQ_EXPR ? true : false, type); })
> +       { constant_boolean_node (cmp == EQ_EXPR, type); })
>        (if (val >= prec)
>         (if (ok && zero_val < val)
> -       { constant_boolean_node (cmp == EQ_EXPR ? false : true, type); })
> +       { constant_boolean_node (cmp != EQ_EXPR, type); })
>         (if (ok && (zero_val < 0 || zero_val >= prec))
>         (cmp (bit_and @0 { wide_int_to_tree (type0,
>                                              wi::mask (val, false, prec)); })
> @@ -10612,7 +10612,7 @@ (define_operator_list SYNC_FETCH_AND_AND
>      (if (prec <= MAX_FIXED_MODE_SIZE)
>       (if (tree_int_cst_sgn (@1) < 0 || wi::to_widest (@1) >= prec)
>        (if (zero_val != wi::to_widest (@1))
> -       { constant_boolean_node (op == EQ_EXPR ? false : true, type); })
> +       { constant_boolean_node (op != EQ_EXPR, type); })
>        (if (zero_val < 0 || zero_val >= prec)
>         (op (bit_and @0 { wide_int_to_tree (type0,
>                                            wi::mask (tree_to_uhwi (@1) + 1,
> @@ -11284,7 +11284,7 @@ (define_operator_list SYNC_FETCH_AND_AND
>        (if (integer_zerop (@1))
>         (cmp @0 { build_zero_cst (TREE_TYPE (@0)); }))
>        (if (tree_int_cst_sgn (@1) < 0 || wi::to_widest (@1) > prec)
> -       { constant_boolean_node (cmp == NE_EXPR ? true : false, type); })
> +       { constant_boolean_node (cmp == NE_EXPR, type); })
>        (if (single_use (@2))
>         (cmp (bit_and @0 { wide_int_to_tree (TREE_TYPE (@0),
>                                             wi::mask (tree_to_uhwi (@1),
> @@ -11305,9 +11305,9 @@ (define_operator_list SYNC_FETCH_AND_AND
>        (if (integer_zerop (@1))
>         (cmp2 @0 { build_zero_cst (TREE_TYPE (@0)); }))
>        (if (tree_int_cst_sgn (@1) < 0)
> -       { constant_boolean_node (cmp == GT_EXPR ? true : false, type); })
> +       { constant_boolean_node (cmp == GT_EXPR, type); })
>        (if (wi::to_widest (@1) >= prec)
> -       { constant_boolean_node (cmp == GT_EXPR ? false : true, type); })
> +       { constant_boolean_node (cmp != GT_EXPR, type); })
>        (if (wi::to_widest (@1) == prec - 1)
>         (cmp3 @0 { wide_int_to_tree (TREE_TYPE (@0),
>                                     wi::shifted_mask (prec - 1, 1,
> --- gcc/gimple-pretty-print.cc.jj       2026-03-27 10:17:14.165330233 +0100
> +++ gcc/gimple-pretty-print.cc  2026-07-31 15:21:17.902970820 +0200
> @@ -3023,8 +3023,7 @@ dump_phi_nodes (pretty_printer *pp, basi
>        if (!virtual_operand_p (gimple_phi_result (phi)) || (flags & TDF_VOPS))
>          {
>            INDENT (indent);
> -         dump_gimple_phi (pp, phi, indent,
> -                          (flags & TDF_GIMPLE) ? false : true, flags);
> +         dump_gimple_phi (pp, phi, indent, (flags & TDF_GIMPLE) == 0, flags);

I thought you would have used `!(flags & TDF_GIMPLE)` here. I see both
` == 0` and `!` are used in the sources but `!` is used more with the
TDF_* flags.

Thanks,
Andrea

>            pp_newline (pp);
>          }
>      }
> --- gcc/fortran/expr.cc.jj      2026-07-29 10:01:14.292373398 +0200
> +++ gcc/fortran/expr.cc 2026-07-31 15:25:27.963898620 +0200
> @@ -3413,7 +3413,7 @@ gfc_check_init_expr (gfc_expr *e)
>        break;
>
>      case EXPR_STRUCTURE:
> -      t = e->ts.is_iso_c ? true : false;
> +      t = e->ts.is_iso_c;
>        if (t)
>         break;
>
> @@ -6112,7 +6112,7 @@ gfc_expr_check_typed (gfc_expr* e, gfc_n
>    check_typed_ns = ns;
>    error_found = gfc_traverse_expr (e, NULL, &expr_check_typed_help, 0);
>
> -  return error_found ? false : true;
> +  return !error_found;
>  }
>
>
> --- gcc/fortran/parse.cc.jj     2026-07-30 22:43:17.993110629 +0200
> +++ gcc/fortran/parse.cc        2026-07-31 15:22:31.631065011 +0200
> @@ -2129,7 +2129,7 @@ gfc_find_state (gfc_compile_state state)
>      if (p->state == state)
>        break;
>
> -  return (p == NULL) ? false : true;
> +  return p != NULL;
>  }
>
>
> --- gcc/fortran/resolve.cc.jj   2026-07-30 22:43:17.995110605 +0200
> +++ gcc/fortran/resolve.cc      2026-07-31 15:22:54.200787725 +0200
> @@ -3292,7 +3292,7 @@ impure_stmt_fcn (gfc_expr *e, gfc_symbol
>         || e->symtree->n.sym->attr.proc == PROC_ST_FUNCTION)
>      return false;
>
> -  return gfc_pure_function (e, &name) ? false : true;
> +  return !gfc_pure_function (e, &name);
>  }
>
>
> --- gcc/fortran/arith.cc.jj     2026-03-27 10:17:14.129330821 +0100
> +++ gcc/fortran/arith.cc        2026-07-31 15:24:08.186878747 +0200
> @@ -354,7 +354,7 @@ gfc_check_character_range (gfc_char_t c,
>      return true;
>
>    if (kind == 1)
> -    return c <= 255 ? true : false;
> +    return c <= 255;
>
>    gcc_unreachable ();
>  }
> --- gcc/fortran/array.cc.jj     2026-03-27 10:17:14.129330821 +0100
> +++ gcc/fortran/array.cc        2026-07-31 15:24:20.620725987 +0200
> @@ -2118,7 +2118,7 @@ is_constant_element (gfc_expr *e)
>    rv = gfc_is_constant_expr (e);
>    gfc_free_expr (e);
>
> -  return rv ? true : false;
> +  return rv;
>  }
>
>
> --- gcc/fortran/decl.cc.jj      2026-07-01 11:54:41.893877858 +0200
> +++ gcc/fortran/decl.cc 2026-07-31 15:24:49.210374739 +0200
> @@ -6592,8 +6592,7 @@ bool
>  gfc_verify_c_interop (gfc_typespec *ts)
>  {
>    if (ts->type == BT_DERIVED && ts->u.derived != NULL)
> -    return (ts->u.derived->ts.is_c_interop || ts->u.derived->attr.is_bind_c)
> -          ? true : false;
> +    return ts->u.derived->ts.is_c_interop || ts->u.derived->attr.is_bind_c;
>    else if (ts->type == BT_CLASS)
>      return false;
>    else if (ts->is_c_interop != 1 && ts->type != BT_ASSUMED)
> --- gcc/fortran/interface.cc.jj 2026-07-16 09:44:33.624721933 +0200
> +++ gcc/fortran/interface.cc    2026-07-31 15:25:41.168736386 +0200
> @@ -1398,7 +1398,7 @@ gfc_check_dummy_characteristics (gfc_sym
>                                  int err_len)
>  {
>    if (s1 == NULL || s2 == NULL)
> -    return s1 == s2 ? true : false;
> +    return s1 == s2;
>
>    if (s1->attr.proc == PROC_ST_FUNCTION || s2->attr.proc == PROC_ST_FUNCTION)
>      {
> --- gcc/fortran/io.cc.jj        2026-07-08 11:10:07.737602225 +0200
> +++ gcc/fortran/io.cc   2026-07-31 15:26:20.567252342 +0200
> @@ -2223,7 +2223,7 @@ check_open_constraints (gfc_open *open,
>      } \
>  }
>
> -  bool warn = (open->err || open->iostat) ? true : false;
> +  bool warn = open->err || open->iostat;
>
>    /* Checks on the ACCESS specifier.  */
>    if (open->access && open->access->expr_type == EXPR_CONSTANT)
> @@ -2750,7 +2750,7 @@ cleanup:
>  static bool
>  check_close_constraints (gfc_close *close, locus *where)
>  {
> -  bool warn = (close->iostat || close->err) ? true : false;
> +  bool warn = close->iostat || close->err;
>
>    if (close->unit == NULL)
>      {
> @@ -3842,7 +3842,7 @@ if (condition) \
>    gfc_symbol *sym = NULL;
>    bool warn, unformatted;
>
> -  warn = (dt->err || dt->iostat) ? true : false;
> +  warn = dt->err || dt->iostat;
>    unformatted = dt->format_expr == NULL && dt->format_label == NULL
>                 && dt->namelist == NULL;
>
> --- gcc/jit/jit-recording.cc.jj 2026-03-27 10:17:14.213329450 +0100
> +++ gcc/jit/jit-recording.cc    2026-07-31 15:27:38.548294293 +0200
> @@ -1546,7 +1546,7 @@ recording::context::set_bool_option (enu
>                  "unrecognized (enum gcc_jit_bool_option) value: %i", opt);
>        return;
>      }
> -  m_bool_options[opt] = value ? true : false;
> +  m_bool_options[opt] = value;
>    log_bool_option (opt);
>  }
>
> @@ -1555,7 +1555,7 @@ recording::context::set_inner_bool_optio
>                                            int value)
>  {
>    gcc_assert (inner_opt >= 0 && inner_opt < NUM_INNER_BOOL_OPTIONS);
> -  m_inner_bool_options[inner_opt] = value ? true : false;
> +  m_inner_bool_options[inner_opt] = value;
>    log_inner_bool_option (inner_opt);
>  }
>
>
>         Jakub
>