On Wed, May 7, 2025 at 3:50 AM Andrew Pinski <quic_apin...@quicinc.com> wrote:
>
> While fixing up how rewrite_to_defined_overflow works, gcc.dg/Wrestrict-22.c
> started
> to fail. This is because `d p+ 2` would moved by LIM and then be rewritten
> not using
> pointer plus. The rewriting part is correct behavior. It only recently
> started to be
> moved out; due to r16-190-g6901d56fea2132.
> Which has the following comment:
> ```
> When we run before PRE and PRE is active hoist all expressions
> since PRE would do so anyway and we can preserve range info
> but PRE cannot.
> ```
> This is not true if hoisting past the always executed point; so, instead of
> hoisting
> these statements all the way out of the max loops, take into account the
> always executed
> loop too.
>
> Bootstrapped and tested on x86_64-linux-gnu.
OK.
Thanks,
Richard.
> gcc/ChangeLog:
>
> * tree-ssa-loop-im.cc (compute_invariantness): Hoist to the always
> executed point
> if ignorning the cost.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/tree-ssa-loop-im.cc | 22 +++++++++++++++++-----
> 1 file changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/gcc/tree-ssa-loop-im.cc b/gcc/tree-ssa-loop-im.cc
> index a3ca5af3e3e..b7f9f9befa5 100644
> --- a/gcc/tree-ssa-loop-im.cc
> +++ b/gcc/tree-ssa-loop-im.cc
> @@ -1241,12 +1241,24 @@ compute_invariantness (basic_block bb)
> lim_data->cost);
> }
>
> - if (lim_data->cost >= LIM_EXPENSIVE
> - /* When we run before PRE and PRE is active hoist all expressions
> - since PRE would do so anyway and we can preserve range info
> - but PRE cannot. */
> - || (flag_tree_pre && !in_loop_pipeline))
> + if (lim_data->cost >= LIM_EXPENSIVE)
> set_profitable_level (stmt);
> + /* When we run before PRE and PRE is active hoist all expressions
> + to the always executed loop since PRE would do so anyway
> + and we can preserve range info while PRE cannot. */
> + else if (flag_tree_pre && !in_loop_pipeline
> + && outermost)
> + {
> + class loop *mloop = lim_data->max_loop;
> + if (loop_depth (outermost) > loop_depth (mloop))
> + {
> + mloop = outermost;
> + if (dump_file && (dump_flags & TDF_DETAILS))
> + fprintf (dump_file, " constraining to loop depth %d\n\n\n",
> + loop_depth (mloop));
> + }
> + set_level (stmt, bb->loop_father, mloop);
> + }
> }
> }
>
> --
> 2.34.1
>
