On Mon, 13 Feb 2017, Jakub Jelinek wrote:
> On Mon, Feb 13, 2017 at 09:59:12AM +0100, Richard Biener wrote:
> > On Sun, 12 Feb 2017, Marc Glisse wrote:
> >
> > > On Sun, 12 Feb 2017, Marc Glisse wrote:
> > >
> > > > On Tue, 7 Feb 2017, Jakub Jelinek wrote:
> > > >
> > > > > * tree-vrp.c (simplify_div_or_mod_using_ranges): If op1 is not
> > > > > constant, but SSA_NAME with a known integer range, use the
> > > > > minimum
> > > > > of that range instead of op1 to determine if modulo can be
> > > > > replaced
> > > > > with its first operand.
> > > >
> > > > Would it make sense to use something like the operand_less_p helper so
> > > > we
> > > > would also handle an INTEGER_CST lhs?
> > >
> > > Oops, operand_less_p is just a helper for compare_values_warnv and even
> > > that
> > > one doesn't seem to use ranges, so there may not already be a nice
> > > function we
> > > can call (?). The idea remains that reusing such code would help handle
> > > more
> > > cases (it may even handle a few symbolic cases).
> >
> > Yeah, we only have the compare_range_with_value / compare_ranges functions
> > and those require you to "expand" the value you have a range for first.
>
> I think we can do something like following, but not sure how you want to
> actually simplify it using helpers. The only thing I can think of is
> something like get_value_range that works on both SSA_NAMEs and
> INTEGER_CSTs, but then it either has to allocate a new value range struct
> for the INTEGER_CST case, or be more like extract_range_from_tree and
> then it would copy the range for the SSA_NAME case, penalizing the code.
You'd of course allocate it on the stack. But yeah, sth like your patch
works for me.
Richard.
> 2017-02-13 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/79408
> * tree-vrp.c (simplify_div_or_mod_using_ranges): Handle also the
> case when on TRUNC_MOD_EXPR op0 is INTEGER_CST.
> (simplify_stmt_using_ranges): Call simplify_div_or_mod_using_ranges
> also if rhs1 is INTEGER_CST.
>
> * gcc.dg/tree-ssa/pr79408-2.c: New test.
>
> --- gcc/tree-vrp.c.jj 2017-02-08 10:21:31.000000000 +0100
> +++ gcc/tree-vrp.c 2017-02-13 10:55:00.755070795 +0100
> @@ -9241,8 +9241,24 @@ simplify_div_or_mod_using_ranges (gimple
> tree val = NULL;
> tree op0 = gimple_assign_rhs1 (stmt);
> tree op1 = gimple_assign_rhs2 (stmt);
> + tree op0min = NULL_TREE, op0max = NULL_TREE;
> tree op1min = op1;
> - value_range *vr = get_value_range (op0);
> + value_range *vr = NULL;
> +
> + if (TREE_CODE (op0) == INTEGER_CST)
> + {
> + op0min = op0;
> + op0max = op0;
> + }
> + else
> + {
> + vr = get_value_range (op0);
> + if (range_int_cst_p (vr))
> + {
> + op0min = vr->min;
> + op0max = vr->max;
> + }
> + }
>
> if (rhs_code == TRUNC_MOD_EXPR
> && TREE_CODE (op1) == SSA_NAME)
> @@ -9254,13 +9270,13 @@ simplify_div_or_mod_using_ranges (gimple
> if (rhs_code == TRUNC_MOD_EXPR
> && TREE_CODE (op1min) == INTEGER_CST
> && tree_int_cst_sgn (op1min) == 1
> - && range_int_cst_p (vr)
> - && tree_int_cst_lt (vr->max, op1min))
> + && op0max
> + && tree_int_cst_lt (op0max, op1min))
> {
> if (TYPE_UNSIGNED (TREE_TYPE (op0))
> - || tree_int_cst_sgn (vr->min) >= 0
> + || tree_int_cst_sgn (op0min) >= 0
> || tree_int_cst_lt (fold_unary (NEGATE_EXPR, TREE_TYPE (op1min),
> op1min),
> - vr->min))
> + op0min))
> {
> /* If op0 already has the range op0 % op1 has,
> then TRUNC_MOD_EXPR won't change anything. */
> @@ -9269,6 +9285,9 @@ simplify_div_or_mod_using_ranges (gimple
> }
> }
>
> + if (TREE_CODE (op0) != SSA_NAME)
> + return false;
> +
> if (!integer_pow2p (op1))
> {
> /* X % -Y can be only optimized into X % Y either if
> @@ -10377,7 +10396,8 @@ simplify_stmt_using_ranges (gimple_stmt_
> range. */
> case TRUNC_DIV_EXPR:
> case TRUNC_MOD_EXPR:
> - if (TREE_CODE (rhs1) == SSA_NAME
> + if ((TREE_CODE (rhs1) == SSA_NAME
> + || TREE_CODE (rhs1) == INTEGER_CST)
> && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
> return simplify_div_or_mod_using_ranges (gsi, stmt);
> break;
> --- gcc/testsuite/gcc.dg/tree-ssa/pr79408-2.c.jj 2017-02-13
> 10:51:13.939063664 +0100
> +++ gcc/testsuite/gcc.dg/tree-ssa/pr79408-2.c 2017-02-13 10:52:33.868008990
> +0100
> @@ -0,0 +1,34 @@
> +/* PR tree-optimization/79408 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +
> +void link_error (void);
> +
> +void
> +foo (unsigned int y)
> +{
> + if (y <= 7312)
> + return;
> + if (7312 % y != 7312)
> + link_error ();
> +}
> +
> +void
> +bar (int x, int y)
> +{
> + if (y <= 7312)
> + return;
> + if (7312 % y != 7312)
> + link_error ();
> +}
> +
> +void
> +baz (int x, int y)
> +{
> + if (y <= 7312)
> + return;
> + if (-7312 % y != -7312)
> + link_error ();
> +}
> +
> +/* { dg-final { scan-tree-dump-times "link_error" 0 "optimized"} } */
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
