On Fri, Jan 17, 2025 at 1:11 AM Andrew Pinski <quic_apin...@quicinc.com> wrote:
>
> This improves this pattern by 2 ways:
> * Allow for an optional convert, similar to how the few other
> `a OP ~a` patterns also allow for an optional convert.
> * Use bitwise_inverted_equal_p/maybe_bit_not instead of directly
> matching bit_not. Just like the other patterns do too.
>
> Note pr118483-2.c used to optimized for aarch64-linux-gnu with GCC 4.9.4
> on the RTL level even though the gimple level was missing it.
OK.
Thanks,
Richard.
> PR tree-optimization/118483
>
> gcc/ChangeLog:
>
> * match.pd (`x ==/!= ~x`): Allow for an optional convert
> and use itwise_inverted_equal_p/maybe_bit_not instead of
> directly matching bit_not.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/pr118483-1.c: New test.
> * gcc.dg/tree-ssa/pr118483-2.c: New test.
> * gcc.dg/tree-ssa/pr118483-3.c: New test.
> * gcc.dg/tree-ssa/pr118483-4.c: New test.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/match.pd | 7 +++++--
> gcc/testsuite/gcc.dg/tree-ssa/pr118483-1.c | 18 ++++++++++++++++++
> gcc/testsuite/gcc.dg/tree-ssa/pr118483-2.c | 18 ++++++++++++++++++
> gcc/testsuite/gcc.dg/tree-ssa/pr118483-3.c | 14 ++++++++++++++
> gcc/testsuite/gcc.dg/tree-ssa/pr118483-4.c | 11 +++++++++++
> 5 files changed, 66 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr118483-1.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr118483-2.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr118483-3.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr118483-4.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index b6cbb851897..5ac7e7417b1 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -6959,8 +6959,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> /* x != ~x -> true */
> (for cmp (eq ne)
> (simplify
> - (cmp:c @0 (bit_not @0))
> - { constant_boolean_node (cmp == NE_EXPR, type); }))
> + (cmp:c (convert? @0) (convert? (maybe_bit_not @1)))
> + (with { bool wascmp; }
> + (if (types_match (TREE_TYPE (@0), TREE_TYPE (@1))
> + && bitwise_inverted_equal_p (@0, @1, wascmp))
> + { constant_boolean_node (cmp == NE_EXPR, type); }))))
>
> /* Fold ~X op ~Y as Y op X. */
> (for cmp (simple_comparison)
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr118483-1.c
> b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-1.c
> new file mode 100644
> index 00000000000..e31876c940a
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-1.c
> @@ -0,0 +1,18 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* PR tree-optimization/118483 */
> +/* { dg-final { scan-tree-dump-not "abort " "optimized" } } */
> +
> +
> +/* The value of `l == e` is always false as it is
> + `(b == 0) == (b != 0)`. */
> +
> +int d;
> +int f(int b)
> +{
> + int e = b == 0;
> + d = e;
> + int l = b != 0;
> + if (l == e)
> + __builtin_abort ();
> +}
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr118483-2.c
> b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-2.c
> new file mode 100644
> index 00000000000..84867719867
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-2.c
> @@ -0,0 +1,18 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* PR tree-optimization/118483 */
> +/* { dg-final { scan-tree-dump-not "abort " "optimized" } } */
> +
> +
> +/* The value of `l == e` is always false as it is
> + `(b == 0) == (b != 0)`. */
> +
> +int d;
> +int f(int b)
> +{
> + int e = b == 0;
> + d = e;
> + int l = !e;
> + if (l == e)
> + __builtin_abort ();
> +}
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr118483-3.c
> b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-3.c
> new file mode 100644
> index 00000000000..65efaf5c30f
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-3.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* PR tree-optimization/118483 */
> +/* { dg-final { scan-tree-dump "return 0;" "optimized" } } */
> +
> +/* This should optimize down to just `return 0;` */
> +/* as `(short)a == ~(short)a` is always false. */
> +int f(int a)
> +{
> + short b = a;
> + int e = ~a;
> + short c = e;
> + return b == c;
> +}
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr118483-4.c
> b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-4.c
> new file mode 100644
> index 00000000000..c6e389c4674
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-4.c
> @@ -0,0 +1,11 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* PR tree-optimization/118483 */
> +/* { dg-final { scan-tree-dump "return 0;" "optimized" } } */
> +
> +/* This should optimize down to just `return 0;` */
> +/* as `a == 0` and `a != 0` are opposites. */
> +int f(int a)
> +{
> + return (a == 0) == (a != 0);
> +}
> --
> 2.43.0
>
