On Wed, Feb 16, 2022 at 05:03:09PM +0800, liuhongt via Gcc-patches wrote:
> > > +(match (cond_expr_convert_p @0 @2 @3 @6)
> > > + (cond (simple_comparison@6 @0 @1) (convert@4 @2) (convert@5 @3))
> > > + (if (types_match (TREE_TYPE (@2), TREE_TYPE (@3))
> >
> > But in principle @2 or @3 could safely differ in sign, you'd then need to
> > ensure
> > to insert sign conversions to @2/@3 to the signedness of @4/@5.
> >
> It turns out differ in sign is not suitable for extension(but ok for
> truncation),
> because it's zero_extend vs sign_extend.
>
> The patch add types_match check when convert is extension.
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> And native Bootstrapped and regtested on CLX.
>
> Ok for trunk?
>
> gcc/ChangeLog:
>
> PR tree-optimization/104551
> PR tree-optimization/103771
> * match.pd (cond_expr_convert_p): Add types_match check when
> convert is extension.
> * tree-vect-patterns.cc
> (gimple_cond_expr_convert_p): Adjust comments.
> (vect_recog_cond_expr_convert_pattern): Ditto.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/i386/pr104551.c: New test.
> ---
> gcc/match.pd | 8 +++++---
> gcc/testsuite/gcc.target/i386/pr104551.c | 24 ++++++++++++++++++++++++
> gcc/tree-vect-patterns.cc | 6 ++++--
> 3 files changed, 33 insertions(+), 5 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr104551.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 05a10ab6bfd..8e80b9f1576 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -7692,11 +7692,13 @@ and,
> (if (INTEGRAL_TYPE_P (type)
> && INTEGRAL_TYPE_P (TREE_TYPE (@2))
> && INTEGRAL_TYPE_P (TREE_TYPE (@0))
> - && INTEGRAL_TYPE_P (TREE_TYPE (@3))
> && TYPE_PRECISION (type) != TYPE_PRECISION (TREE_TYPE (@0))
> && TYPE_PRECISION (TREE_TYPE (@0))
> == TYPE_PRECISION (TREE_TYPE (@2))
> - && TYPE_PRECISION (TREE_TYPE (@0))
> - == TYPE_PRECISION (TREE_TYPE (@3))
> + && (types_match (TREE_TYPE (@2), TREE_TYPE (@3))
> + || ((TYPE_PRECISION (TREE_TYPE (@0))
> + == TYPE_PRECISION (TREE_TYPE (@3)))
> + && INTEGRAL_TYPE_P (TREE_TYPE (@3))
> + && TYPE_PRECISION (TREE_TYPE (@3)) > TYPE_PRECISION (type)))
> && single_use (@4)
> && single_use (@5))))
I find this quite unreadable, it looks like if @2 and @3 are treated
differently. I think keeping the old 3 lines and just adding
&& (TYPE_PRECISION (TREE_TYPE (@0)) >= TYPE_PRECISION (type)
|| (TYPE_UNSIGNED (TREE_TYPE (@2))
== TYPE_UNSIGNED (TREE_TYPE (@3))))
after it ideally with a comment why would be better.
Note, if the precision of @0 and type is the same, I think signedness can
still differ, no?
Jakub
