On Thu, 4 May 2017, Jakub Jelinek wrote:
> Hi!
>
> This patch improves value range computation of BIT_{AND,IOR}_EXPR
> with one singleton range and one range_int_cst_p, where the singleton
> range has n clear least significant bits, then m set bits and either
> that is all it has (i.e. negation of a power of 2), or the bits above
> those two sets of bits are the same for all values in the range (i.e.
> min and max range have those bits identical).
> During x86_64-linux and i686-linux bootstraps together this triggers
> 214000 times, though I have not actually gathered statistics on whether
> the range computed without this patch would be wider in all cases.
You could try to intersect the ranges produced and assert the
result is equal to the new one.
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok.
Thanks,
Richard.
> 2017-05-04 Jakub Jelinek <[email protected]>
>
> PR tree-optimization/80558
> * tree-vrp.c (extract_range_from_binary_expr_1): Optimize
> [x, y] op z into [x op, y op z] for op & or | if conditions
> are met.
>
> * gcc.dg/tree-ssa/vrp115.c: New test.
>
> --- gcc/tree-vrp.c.jj 2017-04-29 18:13:50.000000000 +0200
> +++ gcc/tree-vrp.c 2017-05-03 16:08:44.525256483 +0200
> @@ -3162,8 +3162,59 @@ extract_range_from_binary_expr_1 (value_
> &may_be_nonzero1,
> &must_be_nonzero1);
>
> + if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
> + {
> + value_range *vr0p = NULL, *vr1p = NULL;
> + if (range_int_cst_singleton_p (&vr1))
> + {
> + vr0p = &vr0;
> + vr1p = &vr1;
> + }
> + else if (range_int_cst_singleton_p (&vr0))
> + {
> + vr0p = &vr1;
> + vr1p = &vr0;
> + }
> + /* For op & or | attempt to optimize:
> + [x, y] op z into [x op z, y op z]
> + if z is a constant which (for op | its bitwise not) has n
> + consecutive least significant bits cleared followed by m 1
> + consecutive bits set immediately above it and either
> + m + n == precision, or (x >> (m + n)) == (y >> (m + n)).
> + The least significant n bits of all the values in the range are
> + cleared or set, the m bits above it are preserved and any bits
> + above these are required to be the same for all values in the
> + range. */
> + if (vr0p && range_int_cst_p (vr0p))
> + {
> + wide_int w = vr1p->min;
> + int m = 0, n = 0;
> + if (code == BIT_IOR_EXPR)
> + w = ~w;
> + if (wi::eq_p (w, 0))
> + n = TYPE_PRECISION (expr_type);
> + else
> + {
> + n = wi::ctz (w);
> + w = ~(w | wi::mask (n, false, w.get_precision ()));
> + if (wi::eq_p (w, 0))
> + m = TYPE_PRECISION (expr_type) - n;
> + else
> + m = wi::ctz (w) - n;
> + }
> + wide_int mask = wi::mask (m + n, true, w.get_precision ());
> + if (wi::eq_p (mask & vr0p->min, mask & vr0p->max))
> + {
> + min = int_const_binop (code, vr0p->min, vr1p->min);
> + max = int_const_binop (code, vr0p->max, vr1p->min);
> + }
> + }
> + }
> +
> type = VR_RANGE;
> - if (code == BIT_AND_EXPR)
> + if (min && max)
> + /* Optimized above already. */;
> + else if (code == BIT_AND_EXPR)
> {
> min = wide_int_to_tree (expr_type,
> must_be_nonzero0 & must_be_nonzero1);
> --- gcc/testsuite/gcc.dg/tree-ssa/vrp115.c.jj 2017-05-03 16:12:55.514087451
> +0200
> +++ gcc/testsuite/gcc.dg/tree-ssa/vrp115.c 2017-05-03 16:11:35.000000000
> +0200
> @@ -0,0 +1,50 @@
> +/* PR tree-optimization/80558 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-evrp" } */
> +/* { dg-final { scan-tree-dump-not "link_error" "evrp" } } */
> +
> +void link_error (void);
> +
> +void
> +f1 (int x)
> +{
> + if (x >= 5 && x <= 19)
> + {
> + x &= -2;
> + if (x < 4 || x > 18)
> + link_error ();
> + }
> +}
> +
> +void
> +f2 (int x)
> +{
> + if (x >= 5 && x <= 19)
> + {
> + x |= 7;
> + if (x < 7 || x > 23)
> + link_error ();
> + }
> +}
> +
> +void
> +f3 (int x)
> +{
> + if (x >= -18 && x <= 19)
> + {
> + x |= 7;
> + if (x < -17 || x > 23)
> + link_error ();
> + }
> +}
> +
> +void
> +f4 (int x)
> +{
> + if (x >= 1603 && x <= 2015)
> + {
> + x &= 496;
> + if (x < 64 || x > 464)
> + link_error ();
> + }
> +}
>
> Jakub
>
>
--
Richard Biener <[email protected]>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
