PR 64454: Improve VRP for %

Hello,

here is a rewrite of the patch, using wide_int, and improving a bit the 
result. Same ChangeLog, tested again on x86_64-linux-gnu.

On Fri, May 8, 2015 at 4:59 PM, Marc Glisse <marc.glisse@inria.fr> wrote:
> Hello,
>
> here is a rewrite of the patch, using wide_int, and improving a bit the
> result. Same ChangeLog, tested again on x86_64-linux-gnu.

Please use /* */ for comments.

Otherwise ok!

Thanks,
Richard.

> --
> Marc Glisse
> Index: gcc/testsuite/gcc.dg/tree-ssa/vrp97.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/tree-ssa/vrp97.c       (revision 0)
> +++ gcc/testsuite/gcc.dg/tree-ssa/vrp97.c       (working copy)
> @@ -0,0 +1,19 @@
> +/* PR tree-optimization/64454 */
> +/* { dg-options "-O2 -fdump-tree-vrp1" } */
> +
> +int f(int a, int b)
> +{
> +    if (a < -3 || a > 13) __builtin_unreachable();
> +    if (b < -6 || b > 9) __builtin_unreachable();
> +    int c = a % b;
> +    return c >= -3 && c <= 8;
> +}
> +
> +int g(int a, int b)
> +{
> +  int c = a % b;
> +  return c != -__INT_MAX__ - 1;
> +}
> +
> +/* { dg-final { scan-tree-dump-times "return 1;" 2 "vrp1" } } */
> +/* { dg-final { cleanup-tree-dump "vrp1" } } */
> Index: gcc/testsuite/gcc.dg/vect/slp-perm-7.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/vect/slp-perm-7.c      (revision 222906)
> +++ gcc/testsuite/gcc.dg/vect/slp-perm-7.c      (working copy)
> @@ -63,15 +63,15 @@ int main (int argc, const char* argv[])
>
>    foo (input, output, input2, output2);
>
>    for (i = 0; i < N; i++)
>       if (output[i] != check_results[i] || output2[i] != check_results2[i])
>         abort ();
>
>    return 0;
>  }
>
> -/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  {
> target vect_perm } } } */
> +/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 2 "vect"  {
> target vect_perm } } } */
>  /* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect"
> { target vect_perm } } } */
>  /* { dg-final { cleanup-tree-dump "vect" } } */
>
>
> Index: gcc/tree-vrp.c
> ===================================================================
> --- gcc/tree-vrp.c      (revision 222906)
> +++ gcc/tree-vrp.c      (working copy)
> @@ -3189,40 +3189,73 @@ extract_range_from_binary_expr_1 (value_
>             }
>         }
>        else
>         {
>           extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
>           return;
>         }
>      }
>    else if (code == TRUNC_MOD_EXPR)
>      {
> -      if (vr1.type != VR_RANGE
> -         || range_includes_zero_p (vr1.min, vr1.max) != 0
> -         || vrp_val_is_min (vr1.min))
> +      if (range_is_null (&vr1))
>         {
> -         set_value_range_to_varying (vr);
> +         set_value_range_to_undefined (vr);
>           return;
>         }
> +      // ABS (A % B) < ABS (B) and either 0 <= A % B <= A or A <= A % B <=
> 0.
>        type = VR_RANGE;
> -      /* Compute MAX <|vr1.min|, |vr1.max|> - 1.  */
> -      max = fold_unary_to_constant (ABS_EXPR, expr_type, vr1.min);
> -      if (tree_int_cst_lt (max, vr1.max))
> -       max = vr1.max;
> -      max = int_const_binop (MINUS_EXPR, max, build_int_cst (TREE_TYPE
> (max), 1));
> -      /* If the dividend is non-negative the modulus will be
> -        non-negative as well.  */
> -      if (TYPE_UNSIGNED (expr_type)
> -         || value_range_nonnegative_p (&vr0))
> -       min = build_int_cst (TREE_TYPE (max), 0);
> +      signop sgn = TYPE_SIGN (expr_type);
> +      unsigned int prec = TYPE_PRECISION (expr_type);
> +      wide_int wmin, wmax, tmp;
> +      wide_int zero = wi::zero (prec);
> +      wide_int one = wi::one (prec);
> +      if (vr1.type == VR_RANGE && !symbolic_range_p (&vr1))
> +       {
> +         wmax = wi::sub (vr1.max, one);
> +         if (sgn == SIGNED)
> +           {
> +             tmp = wi::sub (wi::minus_one (prec), vr1.min);
> +             wmax = wi::smax (wmax, tmp);
> +           }
> +       }
> +      else
> +       {
> +         wmax = wi::max_value (prec, sgn);
> +         // X % INT_MIN may be INT_MAX.
> +         if (sgn == UNSIGNED)
> +           wmax = wmax - one;
> +       }
> +
> +      if (sgn == UNSIGNED)
> +       wmin = zero;
>        else
> -       min = fold_unary_to_constant (NEGATE_EXPR, expr_type, max);
> +       {
> +         wmin = -wmax;
> +         if (vr0.type == VR_RANGE && TREE_CODE (vr0.min) == INTEGER_CST)
> +           {
> +             tmp = vr0.min;
> +             if (wi::gts_p (tmp, zero))
> +               tmp = zero;
> +             wmin = wi::smax (wmin, tmp);
> +           }
> +       }
> +
> +      if (vr0.type == VR_RANGE && TREE_CODE (vr0.max) == INTEGER_CST)
> +       {
> +         tmp = vr0.max;
> +         if (sgn == SIGNED && wi::neg_p (tmp))
> +           tmp = zero;
> +         wmax = wi::min (wmax, tmp, sgn);
> +       }
> +
> +      min = wide_int_to_tree (expr_type, wmin);
> +      max = wide_int_to_tree (expr_type, wmax);
>      }
>    else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code ==
> BIT_XOR_EXPR)
>      {
>        bool int_cst_range0, int_cst_range1;
>        wide_int may_be_nonzero0, may_be_nonzero1;
>        wide_int must_be_nonzero0, must_be_nonzero1;
>
>        int_cst_range0 = zero_nonzero_bits_from_vr (expr_type, &vr0,
>                                                   &may_be_nonzero0,
>                                                   &must_be_nonzero0);
>