On Mon, May 27, 2024 at 2:48 AM Andrew Pinski <quic_apin...@quicinc.com> wrote:
>
> While looking into something else, I noticed that `a ^ CST` needed to be
> special casing to bitwise_inverted_equal_p as it would simplify to `a ^ ~CST`
> for the bitwise not.
>
> Bootstrapped and tested on x86_64-linux-gnu with no regressions.
OK.
> PR tree-optimization/115224
>
> gcc/ChangeLog:
>
> * generic-match-head.cc (bitwise_inverted_equal_p): Add `a ^ CST`
> case.
> * gimple-match-head.cc (gimple_bit_xor_cst): New declaration.
> (gimple_bitwise_inverted_equal_p): Add `a ^ CST` case.
> * match.pd (bit_xor_cst): New match.
> (maybe_bit_not): Add bit_xor_cst case.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/bitops-8.c: New test.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/generic-match-head.cc | 10 ++++++++++
> gcc/gimple-match-head.cc | 13 +++++++++++++
> gcc/match.pd | 4 ++++
> gcc/testsuite/gcc.dg/tree-ssa/bitops-8.c | 15 +++++++++++++++
> 4 files changed, 42 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/bitops-8.c
>
> diff --git a/gcc/generic-match-head.cc b/gcc/generic-match-head.cc
> index e2e1e4b2d64..3709fe5456d 100644
> --- a/gcc/generic-match-head.cc
> +++ b/gcc/generic-match-head.cc
> @@ -156,6 +156,16 @@ bitwise_inverted_equal_p (tree expr1, tree expr2, bool
> &wascmp)
> if (TREE_CODE (expr2) == BIT_NOT_EXPR
> && bitwise_equal_p (expr1, TREE_OPERAND (expr2, 0)))
> return true;
> +
> + /* `X ^ CST` and `X ^ ~CST` match for ~. */
> + if (TREE_CODE (expr1) == BIT_XOR_EXPR && TREE_CODE (expr2) == BIT_XOR_EXPR
> + && bitwise_equal_p (TREE_OPERAND (expr1, 0), TREE_OPERAND (expr2, 0)))
> + {
> + tree cst1 = uniform_integer_cst_p (TREE_OPERAND (expr1, 1));
> + tree cst2 = uniform_integer_cst_p (TREE_OPERAND (expr2, 1));
> + if (cst1 && cst2 && wi::to_wide (cst1) == ~wi::to_wide (cst2))
> + return true;
> + }
> if (COMPARISON_CLASS_P (expr1)
> && COMPARISON_CLASS_P (expr2))
> {
> diff --git a/gcc/gimple-match-head.cc b/gcc/gimple-match-head.cc
> index 49b1dde6ae4..d5908f4e9a6 100644
> --- a/gcc/gimple-match-head.cc
> +++ b/gcc/gimple-match-head.cc
> @@ -283,6 +283,7 @@ gimple_bitwise_equal_p (tree expr1, tree expr2, tree
> (*valueize) (tree))
>
> bool gimple_bit_not_with_nop (tree, tree *, tree (*) (tree));
> bool gimple_maybe_cmp (tree, tree *, tree (*) (tree));
> +bool gimple_bit_xor_cst (tree, tree *, tree (*) (tree));
>
> /* Helper function for bitwise_inverted_equal_p macro. */
>
> @@ -299,6 +300,18 @@ gimple_bitwise_inverted_equal_p (tree expr1, tree expr2,
> bool &wascmp, tree (*va
> if (operand_equal_p (expr1, expr2, 0))
> return false;
>
> + tree xor1[2];
> + tree xor2[2];
> + /* `X ^ CST` and `X ^ ~CST` match for ~. */
> + if (gimple_bit_xor_cst (expr1, xor1, valueize)
> + && gimple_bit_xor_cst (expr2, xor2, valueize))
> + {
> + if (operand_equal_p (xor1[0], xor2[0], 0)
> + && (wi::to_wide (uniform_integer_cst_p (xor1[1]))
> + == ~wi::to_wide (uniform_integer_cst_p (xor2[1]))))
> + return true;
> + }
> +
> tree other;
> /* Try if EXPR1 was defined as ~EXPR2. */
> if (gimple_bit_not_with_nop (expr1, &other, valueize))
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 090ad4e08b0..480e36bbbaf 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -174,6 +174,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (match (bit_not_with_nop @0)
> (convert (bit_not @0))
> (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))))
> +(match (bit_xor_cst @0 @1)
> + (bit_xor @0 uniform_integer_cst_p@1))
> (for cmp (tcc_comparison)
> (match (maybe_cmp @0)
> (cmp@0 @1 @2))
> @@ -195,6 +197,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (INTEGER_CST@0))
> (match (maybe_bit_not @0)
> (maybe_cmp@0 @1))
> +(match (maybe_bit_not @0)
> + (bit_xor_cst@0 @1 @2))
>
> /* Transform likes of (char) ABS_EXPR <(int) x> into (char) ABSU_EXPR <x>
> ABSU_EXPR returns unsigned absolute value of the operand and the operand
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bitops-8.c
> b/gcc/testsuite/gcc.dg/tree-ssa/bitops-8.c
> new file mode 100644
> index 00000000000..40f756e4455
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/bitops-8.c
> @@ -0,0 +1,15 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
> +/* PR tree-optimization/115224 */
> +
> +int f1(int a, int b)
> +{
> + a = a ^ 1;
> + int c = ~a;
> + return c | (a ^ b);
> + // ~((a ^ 1) & b) or (a ^ -2) | ~b
> +}
> +/* { dg-final { scan-tree-dump-times "bit_xor_expr, " 1 "optimized" } }
> */
> +/* { dg-final { scan-tree-dump-times "bit_ior_expr, " 1 "optimized" } }
> */
> +/* { dg-final { scan-tree-dump-times "bit_not_expr, " 1 "optimized" } }
> */
> +
> --
> 2.43.0
>
