> Am 09.11.2024 um 05:00 schrieb Andrew Pinski <quic_apin...@quicinc.com>:
>
> This removes an (broken) simplification from fold which is already handled
> in match.
> The reason why it was broken is because of the use of wi::to_wide on the RHS
> of the
> rotate which could be 2 different types even though the LHS was the same type.
> Since it is already handled in match (by the patterns for
> `Turn (a OP c1) OP c2 into a OP (c1+c2).`). It can be removed without losing
> any optimizations.
>
> Bootstrapped and tested on x86_64-linux-gnu.
Ok
Richard
> PR middle-end/117492
>
> gcc/ChangeLog:
>
> * fold-const.cc (fold_binary_loc): Remove `Two consecutive rotates adding
> up
> to the some integer` simplifcation.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/torture/pr117492-1.c: New test.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/fold-const.cc | 10 ----------
> gcc/testsuite/gcc.dg/torture/pr117492-1.c | 16 ++++++++++++++++
> 2 files changed, 16 insertions(+), 10 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/torture/pr117492-1.c
>
> diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
> index 0e374294c01..1e8ae1ab493 100644
> --- a/gcc/fold-const.cc
> +++ b/gcc/fold-const.cc
> @@ -12530,16 +12530,6 @@ fold_binary_loc (location_t loc, enum tree_code
> code, tree type,
> arg01, arg1));
> }
>
> - /* Two consecutive rotates adding up to the some integer
> - multiple of the precision of the type can be ignored. */
> - if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
> - && TREE_CODE (arg0) == RROTATE_EXPR
> - && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
> - && wi::umod_trunc (wi::to_wide (arg1)
> - + wi::to_wide (TREE_OPERAND (arg0, 1)),
> - prec) == 0)
> - return fold_convert_loc (loc, type, TREE_OPERAND (arg0, 0));
> -
> return NULL_TREE;
>
> case MIN_EXPR:
> diff --git a/gcc/testsuite/gcc.dg/torture/pr117492-1.c
> b/gcc/testsuite/gcc.dg/torture/pr117492-1.c
> new file mode 100644
> index 00000000000..543d8b7e709
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/torture/pr117492-1.c
> @@ -0,0 +1,16 @@
> +/* { dg-do compile } */
> +/* PR middle-end/117492 */
> +
> +/* This code would ICE in fold due to code which was using wi::to_wide with
> different types
> + and adding them. */
> +
> +typedef unsigned u;
> +
> +u
> +foo(u x)
> +{
> + return
> + __builtin_stdc_rotate_left((unsigned)
> + __builtin_stdc_rotate_right(x, 0x100000001ull),
> + 1);
> +}
> --
> 2.43.0
>
