On Fri, 22 Jul 2016, Patrick Palka wrote:
> This patch teaches VRP to register along a default switch label
> assertions that corresponds to the anti range of each case label.
>
> Does this look OK to commit after bootstrap + regtest on
> x86_64-pc-linux-gnu?
Forgot the changelog:
gcc/ChangeLog:
PR tree-optimization/18046
* tree-vrp.c (find_switch_asserts): Register edge assertions
for the default label which correspond to the anti-ranges
of each non-case label.
gcc/testsuite/ChangeLog:
PR tree-optimization/18046
* gcc.dg/tree-ssa/ssa-dom-thread-6.c: Bump FSM count to 5.
* gcc.dg/tree-ssa/vrp103.c: New test.
* gcc.dg/tree-ssa/vrp104.c: New test.
> ---
> gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-6.c | 2 +-
> gcc/testsuite/gcc.dg/tree-ssa/vrp103.c | 30 ++++++++++++++++++
> gcc/testsuite/gcc.dg/tree-ssa/vrp104.c | 32 +++++++++++++++++++
> gcc/tree-vrp.c | 39
> ++++++++++++++++++++++--
> 4 files changed, 100 insertions(+), 3 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/vrp103.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/vrp104.c
>
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-6.c
> b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-6.c
> index 5ec4687..551fbac 100644
> --- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-6.c
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-6.c
> @@ -1,7 +1,7 @@
> /* { dg-do compile } */
> /* { dg-options "-O2 -fdump-tree-thread1-details
> -fdump-tree-thread2-details" } */
> /* { dg-final { scan-tree-dump-times "FSM" 3 "thread1" } } */
> -/* { dg-final { scan-tree-dump-times "FSM" 4 "thread2" } } */
> +/* { dg-final { scan-tree-dump-times "FSM" 5 "thread2" } } */
>
> int sum0, sum1, sum2, sum3;
> int foo (char *s, char **ret)
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp103.c
> b/gcc/testsuite/gcc.dg/tree-ssa/vrp103.c
> new file mode 100644
> index 0000000..eea98bb
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp103.c
> @@ -0,0 +1,30 @@
> +/* PR tree-optimization/18046 */
> +/* { dg-options "-O2 -fdump-tree-vrp" } */
> +/* { dg-final { scan-tree-dump-times "baz \\(0\\);" 4 "vrp1" } } */
> +
> +void foo ();
> +void bar ();
> +void baz (int);
> +
> +void
> +test (int i)
> +{
> + switch (i)
> + {
> + case 1:
> + case 2:
> + case 3:
> + foo ();
> + break;
> + case 5:
> + bar ();
> + break;
> + default:
> + /* These tests should be folded to 0, resulting in 4 calls to bar (0).
> */
> + baz (i == 1);
> + baz (i == 2);
> + baz (i == 3);
> + baz (i == 5);
> + break;
> + }
> +}
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp104.c
> b/gcc/testsuite/gcc.dg/tree-ssa/vrp104.c
> new file mode 100644
> index 0000000..6410847
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp104.c
> @@ -0,0 +1,32 @@
> +/* PR tree-optimization/18046 */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* { dg-final { scan-tree-dump-times "switch" 1 "optimized" } } */
> +
> +void foo ();
> +void bar ();
> +
> +void
> +test (int i)
> +{
> + switch (i)
> + {
> + case 1:
> + foo ();
> + break;
> + case 2:
> + bar ();
> + break;
> + default:
> + break;
> + }
> +
> + /* This switch should be gone after threading/VRP. */
> + switch (i)
> + {
> + case 1:
> + foo ();
> + break;
> + default:
> + break;
> + }
> +}
> diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
> index 06364b7..32a4de3 100644
> --- a/gcc/tree-vrp.c
> +++ b/gcc/tree-vrp.c
> @@ -5917,6 +5917,7 @@ find_switch_asserts (basic_block bb, gswitch *last)
> ci[idx].expr = gimple_switch_label (last, idx);
> ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr));
> }
> + edge default_edge = find_edge (bb, ci[0].bb);
> qsort (ci, n, sizeof (struct case_info), compare_case_labels);
>
> for (idx = 0; idx < n; ++idx)
> @@ -5945,8 +5946,8 @@ find_switch_asserts (basic_block bb, gswitch *last)
> max = CASE_LOW (ci[idx].expr);
> }
>
> - /* Nothing to do if the range includes the default label until we
> - can register anti-ranges. */
> + /* Can't extract a useful assertion out of a range that includes the
> + default label. */
> if (min == NULL_TREE)
> continue;
>
> @@ -5963,6 +5964,40 @@ find_switch_asserts (basic_block bb, gswitch *last)
> fold_convert (TREE_TYPE (op), max));
> }
>
> + /* For each case label, register along the default label an assertion that
> + corresponds to the anti-range of that label. */
> + for (idx = 0; idx < n; ++idx)
> + {
> + tree min, max;
> + tree cl = ci[idx].expr;
> +
> + min = CASE_LOW (cl);
> + max = CASE_HIGH (cl);
> +
> + if (min == NULL_TREE)
> + continue;
> +
> + if (max == NULL_TREE)
> + {
> + /* Register the assertion OP != MIN. */
> + min = fold_convert (TREE_TYPE (op), min);
> + register_edge_assert_for (op, default_edge, bsi, NE_EXPR, op, min);
> + }
> + else
> + {
> + /* Register the assertion (unsigned)OP - MIN > (MAX - MIN),
> + which will give OP the anti-range ~[MIN,MAX]. */
> + tree uop = fold_convert (unsigned_type_for (TREE_TYPE (op)), op);
> + min = fold_convert (TREE_TYPE (uop), min);
> + max = fold_convert (TREE_TYPE (uop), max);
> +
> + tree lhs = fold_build2 (MINUS_EXPR, TREE_TYPE (uop), uop, min);
> + tree rhs = int_const_binop (MINUS_EXPR, max, min);
> + register_new_assert_for (op, lhs, GT_EXPR, rhs,
> + NULL, default_edge, bsi);
> + }
> + }
> +
> XDELETEVEC (ci);
> }
>
> --
> 2.9.2.413.g76d2a70
>
>
