Re: [PATCH] Don't check can_vec_perm_const_p for nonlinear iv_init when it's constant.

[Hongtao Liu via Gcc-patches]

On Wed, Sep 21, 2022 at 3:41 PM Richard Biener via Gcc-patches
 wrote:
>
> On Wed, Sep 21, 2022 at 1:41 AM liuhongt via Gcc-patches
>  wrote:
> >
> > When init_expr is INTEGER_CST or REAL_CST, can_vec_perm_const_p is not
> > necessary since there's no real vec_perm needed, but
> > vec_gen_perm_mask_checked will gcc_assert (can_vec_perm_const_p). So
> > it's better to use vec_gen_perm_mask_any in
> > vect_create_nonlinear_iv_init.
>
> and the VEC_PERM build will fold the permute away?
Yes, it's just a const vector. [ c, -c, c, c, .. ].
>
> > Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> > Ok for trunk?
>
> OK.
>
> Thanks,
> Richard.
>
> > gcc/ChangeLog:
> >
> > PR tree-optimization/106963
> > * tree-vect-loop.cc (vect_create_nonlinear_iv_init): Use
> > vec_gen_perm_mask_any instead of vec_gen_perm_mask_check.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * gcc.target/i386/pr106963.c: New test.
> > ---
> >  gcc/testsuite/gcc.target/i386/pr106963.c | 14 ++
> >  gcc/tree-vect-loop.cc|  5 -
> >  2 files changed, 18 insertions(+), 1 deletion(-)
> >  create mode 100644 gcc/testsuite/gcc.target/i386/pr106963.c
> >
> > diff --git a/gcc/testsuite/gcc.target/i386/pr106963.c 
> > b/gcc/testsuite/gcc.target/i386/pr106963.c
> > new file mode 100644
> > index 000..9f2d20e2523
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr106963.c
> > @@ -0,0 +1,14 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mavx -mno-avx2" } */
> > +
> > +void
> > +foo_neg_const (int *a)
> > +{
> > +  int i, b = 1;
> > +
> > +  for (i = 0; i < 1000; i++)
> > +{
> > +  a[i] = b;
> > +  b = -b;
> > +}
> > +}
> > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
> > index 9c434b66c5b..aabdc6f2d81 100644
> > --- a/gcc/tree-vect-loop.cc
> > +++ b/gcc/tree-vect-loop.cc
> > @@ -8356,8 +8356,11 @@ vect_create_nonlinear_iv_init (gimple_seq* stmts, 
> > tree init_expr,
> > sel[2 * i + 1] = i + nunits;
> >   }
> > vec_perm_indices indices (sel, 2, nunits);
> > +   /* Don't use vect_gen_perm_mask_checked since can_vec_perm_const_p 
> > may
> > +  fail when vec_init is const vector. In that situation vec_perm 
> > is not
> > +  really needed.  */
> > tree perm_mask_even
> > - = vect_gen_perm_mask_checked (vectype, indices);
> > + = vect_gen_perm_mask_any (vectype, indices);
> > vec_init = gimple_build (stmts, VEC_PERM_EXPR,
> >  vectype,
> >  vec_init, vec_neg,
> > --
> > 2.18.1
> >



-- 
BR,
Hongtao

Re: [PATCH] Don't check can_vec_perm_const_p for nonlinear iv_init when it's constant.

[Richard Biener via Gcc-patches]

On Wed, Sep 21, 2022 at 1:41 AM liuhongt via Gcc-patches
 wrote:
>
> When init_expr is INTEGER_CST or REAL_CST, can_vec_perm_const_p is not
> necessary since there's no real vec_perm needed, but
> vec_gen_perm_mask_checked will gcc_assert (can_vec_perm_const_p). So
> it's better to use vec_gen_perm_mask_any in
> vect_create_nonlinear_iv_init.

and the VEC_PERM build will fold the permute away?

> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> Ok for trunk?

OK.

Thanks,
Richard.

> gcc/ChangeLog:
>
> PR tree-optimization/106963
> * tree-vect-loop.cc (vect_create_nonlinear_iv_init): Use
> vec_gen_perm_mask_any instead of vec_gen_perm_mask_check.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/i386/pr106963.c: New test.
> ---
>  gcc/testsuite/gcc.target/i386/pr106963.c | 14 ++
>  gcc/tree-vect-loop.cc|  5 -
>  2 files changed, 18 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr106963.c
>
> diff --git a/gcc/testsuite/gcc.target/i386/pr106963.c 
> b/gcc/testsuite/gcc.target/i386/pr106963.c
> new file mode 100644
> index 000..9f2d20e2523
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr106963.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mavx -mno-avx2" } */
> +
> +void
> +foo_neg_const (int *a)
> +{
> +  int i, b = 1;
> +
> +  for (i = 0; i < 1000; i++)
> +{
> +  a[i] = b;
> +  b = -b;
> +}
> +}
> diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
> index 9c434b66c5b..aabdc6f2d81 100644
> --- a/gcc/tree-vect-loop.cc
> +++ b/gcc/tree-vect-loop.cc
> @@ -8356,8 +8356,11 @@ vect_create_nonlinear_iv_init (gimple_seq* stmts, tree 
> init_expr,
> sel[2 * i + 1] = i + nunits;
>   }
> vec_perm_indices indices (sel, 2, nunits);
> +   /* Don't use vect_gen_perm_mask_checked since can_vec_perm_const_p may
> +  fail when vec_init is const vector. In that situation vec_perm is 
> not
> +  really needed.  */
> tree perm_mask_even
> - = vect_gen_perm_mask_checked (vectype, indices);
> + = vect_gen_perm_mask_any (vectype, indices);
> vec_init = gimple_build (stmts, VEC_PERM_EXPR,
>  vectype,
>  vec_init, vec_neg,
> --
> 2.18.1
>

[PATCH] Don't check can_vec_perm_const_p for nonlinear iv_init when it's constant.

[liuhongt via Gcc-patches]

When init_expr is INTEGER_CST or REAL_CST, can_vec_perm_const_p is not
necessary since there's no real vec_perm needed, but
vec_gen_perm_mask_checked will gcc_assert (can_vec_perm_const_p). So
it's better to use vec_gen_perm_mask_any in
vect_create_nonlinear_iv_init.

Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ok for trunk?

gcc/ChangeLog:

PR tree-optimization/106963
* tree-vect-loop.cc (vect_create_nonlinear_iv_init): Use
vec_gen_perm_mask_any instead of vec_gen_perm_mask_check.

gcc/testsuite/ChangeLog:

* gcc.target/i386/pr106963.c: New test.
---
 gcc/testsuite/gcc.target/i386/pr106963.c | 14 ++
 gcc/tree-vect-loop.cc|  5 -
 2 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr106963.c

diff --git a/gcc/testsuite/gcc.target/i386/pr106963.c 
b/gcc/testsuite/gcc.target/i386/pr106963.c
new file mode 100644
index 000..9f2d20e2523
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr106963.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mavx -mno-avx2" } */
+
+void
+foo_neg_const (int *a)
+{
+  int i, b = 1;
+
+  for (i = 0; i < 1000; i++)
+{
+  a[i] = b;
+  b = -b;
+}
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 9c434b66c5b..aabdc6f2d81 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -8356,8 +8356,11 @@ vect_create_nonlinear_iv_init (gimple_seq* stmts, tree 
init_expr,
sel[2 * i + 1] = i + nunits;
  }
vec_perm_indices indices (sel, 2, nunits);
+   /* Don't use vect_gen_perm_mask_checked since can_vec_perm_const_p may
+  fail when vec_init is const vector. In that situation vec_perm is not
+  really needed.  */
tree perm_mask_even
- = vect_gen_perm_mask_checked (vectype, indices);
+ = vect_gen_perm_mask_any (vectype, indices);
vec_init = gimple_build (stmts, VEC_PERM_EXPR,
 vectype,
 vec_init, vec_neg,
-- 
2.18.1