On Thu, Sep 14, 2023 at 7:49 PM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> I had missed that integer_onep can match vector types with uniform constant
> of `1`.
> This means the shifter could be an scalar type and then doing a comparison
> against `0`
> would be an invalid transformation.
> This fixes the problem by adding a check for the type of the integer_onep to
> make
> sure it is a INTEGRAL_TYPE_P (which does not match a vector type).
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
OK.
> PR tree-optimization/111414
>
> gcc/ChangeLog:
>
> * match.pd (`(1 >> X) != 0`): Check to see if
> the integer_onep was an integral type (not a vector type).
>
> gcc/testsuite/ChangeLog:
>
> * gcc.c-torture/compile/pr111414-1.c: New test.
> ---
> gcc/match.pd | 5 +++--
> gcc/testsuite/gcc.c-torture/compile/pr111414-1.c | 13 +++++++++++++
> 2 files changed, 16 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr111414-1.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 07ffd831132..97db0eb5f25 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -4206,8 +4206,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> /* `(1 >> X) != 0` -> `X == 0` */
> /* `(1 >> X) == 0` -> `X != 0` */
> (simplify
> - (cmp (rshift integer_onep @0) integer_zerop)
> - (icmp @0 { build_zero_cst (TREE_TYPE (@0)); })))
> + (cmp (rshift integer_onep@1 @0) integer_zerop)
> + (if (INTEGRAL_TYPE_P (TREE_TYPE (@1)))
> + (icmp @0 { build_zero_cst (TREE_TYPE (@0)); }))))
>
> /* (CST1 << A) == CST2 -> A == ctz (CST2) - ctz (CST1)
> (CST1 << A) != CST2 -> A != ctz (CST2) - ctz (CST1)
> diff --git a/gcc/testsuite/gcc.c-torture/compile/pr111414-1.c
> b/gcc/testsuite/gcc.c-torture/compile/pr111414-1.c
> new file mode 100644
> index 00000000000..13fbdae7230
> --- /dev/null
> +++ b/gcc/testsuite/gcc.c-torture/compile/pr111414-1.c
> @@ -0,0 +1,13 @@
> +int a, b, c, d, e, f, g;
> +int h(int i) { return b >= 2 ?: i >> b; }
> +void j() {
> + int k;
> + int *l = &c;
> + for (; d; d++) {
> + g = h(0 != j);
> + f = g >> a;
> + k = f << 7;
> + e = k > 5 ? k : 0;
> + *l ^= e;
> + }
> +}
> --
> 2.31.1
>
