diff mbox series

Optimize identical permutation in my last r13-3212-gb88adba751da63

Message ID 20221013031518.66289-1-liwei.xu@intel.com
State Accepted, archived
Headers
Series Optimize identical permutation in my last r13-3212-gb88adba751da63 |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Liwei Xu Oct. 13, 2022, 3:15 a.m. UTC 
  Add extra index check when merging VEC_CST, this handles the case when exactly op1 needs to be return.

This fixes:
	FAIL: gcc.dg/tree-ssa/forwprop-19.c scan-tree-dump-not forwprop1 "VEC_PERM_EXPR"

gcc/ChangeLog:

	PR target/107220
	* match.pd: Check the index of VEC_CST and return the op1 if needed.
---
 gcc/match.pd | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

Comments

Richard Biener Oct. 13, 2022, 10:41 a.m. UTC | #1 
On Thu, Oct 13, 2022 at 5:15 AM Liwei Xu <liwei.xu@intel.com> wrote:
>
> Add extra index check when merging VEC_CST, this handles the case when exactly op1 needs to be return.
>
> This fixes:
>         FAIL: gcc.dg/tree-ssa/forwprop-19.c scan-tree-dump-not forwprop1 "VEC_PERM_EXPR"
>
> gcc/ChangeLog:
>
>         PR target/107220
>         * match.pd: Check the index of VEC_CST and return the op1 if needed.
> ---
>  gcc/match.pd | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 3550c16aaa6..1efdc3abb5d 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -8106,6 +8106,7 @@ and,
>      vec_perm_builder builder0;
>      vec_perm_builder builder1;
>      vec_perm_builder builder2 (nelts, nelts, 1);
> +    bool ident_to_1 = true;
>
>      if (!tree_to_vec_perm_builder (&builder0, @3)
>         || !tree_to_vec_perm_builder (&builder1, @4))
> @@ -8115,7 +8116,15 @@ and,
>      vec_perm_indices sel1 (builder1, 1, nelts);
>
>      for (int i = 0; i < nelts; i++)
> -      builder2.quick_push (sel0[sel1[i].to_constant ()]);
> +      {
> +        int tmp_index = sel0[sel1[i].to_constant ()].to_constant ();
> +        builder2.quick_push (sel0[sel1[i].to_constant ()]);
> +        if ( i != tmp_index)
> +         ident_to_1 = false;
> +      }
> +
> +    if (ident_to_1)
> +      return @1;

You can't "return" in match.pd code.  I think the code was fine and the testcase
can be adjusted to scan the subsequent DSE or DCE pass instead.

The "correct" match.pd approach would be to do the if (ident_to_1) check here:

@@ -8124,7 +8124,9 @@ and,

     op0 = vec_perm_indices_to_tree (TREE_TYPE (@4), sel2);
   }
-  (vec_perm @1 @2 { op0; })))
+  (if (ident_to_1)
+   @1
+   (vec_perm @1 @2 { op0; }))))

I'll see to reject 'return' in c-exprs ;)

Richard.

>
>      vec_perm_indices sel2 (builder2, 2, nelts);
>
> --
> 2.18.2
>
diff mbox series

Patch

diff --git a/gcc/match.pd b/gcc/match.pd
index 3550c16aaa6..1efdc3abb5d 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -8106,6 +8106,7 @@  and,
     vec_perm_builder builder0;
     vec_perm_builder builder1;
     vec_perm_builder builder2 (nelts, nelts, 1);
+    bool ident_to_1 = true;
 
     if (!tree_to_vec_perm_builder (&builder0, @3)
 	|| !tree_to_vec_perm_builder (&builder1, @4))
@@ -8115,7 +8116,15 @@  and,
     vec_perm_indices sel1 (builder1, 1, nelts);
 
     for (int i = 0; i < nelts; i++)
-      builder2.quick_push (sel0[sel1[i].to_constant ()]);
+      {
+	 int tmp_index = sel0[sel1[i].to_constant ()].to_constant ();
+	 builder2.quick_push (sel0[sel1[i].to_constant ()]);
+	 if ( i != tmp_index)
+	  ident_to_1 = false;
+      }
+
+    if (ident_to_1)
+      return @1;
 
     vec_perm_indices sel2 (builder2, 2, nelts);