On Tue, Nov 5, 2024 at 12:10 PM Martin Jambor <mjam...@suse.cz> wrote:
>
> Hi,
>
> When looking into cases where we know an actual argument of a call is
> a constant but we don't generate a singleton value-range for the jump
> function, I found out that the special handling of pointer constants
> does not work well for constant zero pointer values. However, the
> code for other types works well for zeros, so I just added a simple
> test.
>
> With this patch, we generate
>
> [prange] struct S * [0, 0] MASK 0x0 VALUE 0x0
>
> instead of for example:
>
> [prange] struct S * [0, +INF] MASK 0xfffffffffffffff0 VALUE 0x0
>
> for a zero constant passed in a call.
>
> Bootstrapped and tested on x86_64-linux, the whole patch series has
> additionally passed LTO and profiled-LTO bootstrap on the same platform
> and a bootstrap and testsuite on ppc64-linux. Aarch64-linux bootstrap
> and testing is in progress. OK for master is that passes too?
>
> Thanks,
>
> Martin
>
>
> gcc/ChangeLog:
>
> 2024-11-01 Martin Jambor <mjam...@suse.cz>
>
> * ipa-prop.cc (ipa_compute_jump_functions_for_edge): When creating
> value-range jump functions from pointer type constant zero, do so
> as if it was not a pointer.
> ---
> gcc/ipa-prop.cc | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/ipa-prop.cc b/gcc/ipa-prop.cc
> index 9bd2e4bc60c..012f8a32386 100644
> --- a/gcc/ipa-prop.cc
> +++ b/gcc/ipa-prop.cc
> @@ -2368,7 +2368,8 @@ ipa_compute_jump_functions_for_edge (struct
> ipa_func_body_info *fbi,
> }
>
> value_range vr (TREE_TYPE (arg));
> - if (POINTER_TYPE_P (TREE_TYPE (arg)))
> + if (POINTER_TYPE_P (TREE_TYPE (arg))
> + && !zerop (arg))
integer_zerop (arg) - I also think this deserves a comment.
Richard.
> {
> bool addr_nonzero = false;
> bool strict_overflow = false;
> --
> 2.47.0
>
