Konstantinos Eleftheriou <konstantinos.elefther...@vrull.eu> writes:
> From: kelefth <konstantinos.elefther...@vrull.eu>
>
> In expressions like (a != b || ((a ^ b) & CST0) == CST1) and
> (a != b || (a ^ b) == CST), (a ^ b) is folded to false.
> In the equivalent expressions (((a ^ b) & CST0) == CST1 || a != b) and
> ((a ^ b) == CST, (a ^ b) || a != b) this is not happening.
>
> This patch adds the following simplifications in match.pd:
> ((a ^ b) & CST0) == CST1 || a != b --> 0 == (CST1 || a != b)
> (a ^ b) == CST || a != b --> 0 == CST || (a != b)
>
> PR tree-optimization/114326
>
> gcc/ChangeLog:
>
> * match.pd: Add two patterns to fold a ^ b to 0, when a == b.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/fold-xor-and-or-1.c: New test.
> * gcc.dg/tree-ssa/fold-xor-and-or-2.c: New test.
> * gcc.dg/tree-ssa/fold-xor-or-1.c: New test.
> * gcc.dg/tree-ssa/fold-xor-or-2.c: New test.
>
> Reviewed-by: Christoph Müllner <christoph.muell...@vrull.eu>
> Signed-off-by: Philipp Tomsich <philipp.toms...@vrull.eu>
> Signed-off-by: Konstantinos Eleftheriou <konstantinos.elefther...@vrull.eu>
> ---
> gcc/match.pd | 30 +++++++++++++++++++
> .../gcc.dg/tree-ssa/fold-xor-and-or-1.c | 17 +++++++++++
> .../gcc.dg/tree-ssa/fold-xor-and-or-2.c | 19 ++++++++++++
> gcc/testsuite/gcc.dg/tree-ssa/fold-xor-or-1.c | 17 +++++++++++
> gcc/testsuite/gcc.dg/tree-ssa/fold-xor-or-2.c | 19 ++++++++++++
> 5 files changed, 102 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/fold-xor-and-or-1.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/fold-xor-and-or-2.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/fold-xor-or-1.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/fold-xor-or-2.c
>
> [...]
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/fold-xor-and-or-2.c
> @@ -0,0 +1,19 @@
> +/* { dg-do-compile } */
/* { dg-do compile } */
Please fix each instance of that. Thanks!
> [...]
sam
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