diff mbox series

[2/8,v9] middle-end slp: fix is_linear_load_p to prevent multiple answers

Message ID 20201228133615.GA19375@arm.com
State New
Headers show
Series [1/8,v9] middle-end slp: Support optimizing load distribution | expand

Commit Message

Tamar Christina Dec. 28, 2020, 1:36 p.m. UTC 
Hi All,

This fixes an issue where is_linear_load_p could return the incorrect
permutation kind because it is singe pass.

This arranges the candidates in such a way that there won't be any ambiguity so
that the function can still be linear but give correct values.

Bootstrapped Regtested on aarch64-none-linux-gnu, x86_64-pc-linux-gnu
and no issues.

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

	* tree-vect-slp-patterns.c (is_linear_load_p): Fix ambiguity.

--- inline copy of patch -- 
diff --git a/gcc/tree-vect-slp-patterns.c b/gcc/tree-vect-slp-patterns.c
index fede88923af8521ee4954c8ae27b0e589f975610..7fd79d91c6ba4ccdbf361307a6105fb7e46aa961 100644


--

Comments

Richard Biener Jan. 7, 2021, 1:17 p.m. UTC | #1 
On Mon, 28 Dec 2020, Tamar Christina wrote:

> Hi All,
> 
> This fixes an issue where is_linear_load_p could return the incorrect
> permutation kind because it is singe pass.
> 
> This arranges the candidates in such a way that there won't be any ambiguity so
> that the function can still be linear but give correct values.
> 
> Bootstrapped Regtested on aarch64-none-linux-gnu, x86_64-pc-linux-gnu
> and no issues.
> 
> Ok for master?

OK.  I see no testcases in any of the patch in this series though.

Thanks,
Richard.

> Thanks,
> Tamar
> 
> gcc/ChangeLog:
> 
> 	* tree-vect-slp-patterns.c (is_linear_load_p): Fix ambiguity.
> 
> --- inline copy of patch -- 
> diff --git a/gcc/tree-vect-slp-patterns.c b/gcc/tree-vect-slp-patterns.c
> index fede88923af8521ee4954c8ae27b0e589f975610..7fd79d91c6ba4ccdbf361307a6105fb7e46aa961 100644
> --- a/gcc/tree-vect-slp-patterns.c
> +++ b/gcc/tree-vect-slp-patterns.c
> @@ -140,32 +140,32 @@ is_linear_load_p (load_permutation_t loads)
>  
>    unsigned load, i;
>    complex_perm_kinds_t candidates[4]
> -    = { PERM_EVENODD
> -      , PERM_ODDEVEN
> -      , PERM_ODDODD
> +    = { PERM_ODDODD
>        , PERM_EVENEVEN
> +      , PERM_EVENODD
> +      , PERM_ODDEVEN
>        };
>  
>    int valid_patterns = 4;
> -  FOR_EACH_VEC_ELT_FROM (loads, i, load, 1)
> +  FOR_EACH_VEC_ELT (loads, i, load)
>      {
> -      if (candidates[0] != PERM_UNKNOWN && load != i)
> +      if (candidates[0] != PERM_UNKNOWN && load != 1)
>  	{
>  	  candidates[0] = PERM_UNKNOWN;
>  	  valid_patterns--;
>  	}
> -      if (candidates[1] != PERM_UNKNOWN
> -	  && load != (i % 2 == 0 ? i + 1 : i - 1))
> +      if (candidates[1] != PERM_UNKNOWN && load != 0)
>  	{
>  	  candidates[1] = PERM_UNKNOWN;
>  	  valid_patterns--;
>  	}
> -      if (candidates[2] != PERM_UNKNOWN && load != 1)
> +      if (candidates[2] != PERM_UNKNOWN && load != i)
>  	{
>  	  candidates[2] = PERM_UNKNOWN;
>  	  valid_patterns--;
>  	}
> -      if (candidates[3] != PERM_UNKNOWN && load != 0)
> +      if (candidates[3] != PERM_UNKNOWN
> +	  && load != (i % 2 == 0 ? i + 1 : i - 1))
>  	{
>  	  candidates[3] = PERM_UNKNOWN;
>  	  valid_patterns--;
> 
> 
>
diff mbox series

Patch

diff --git a/gcc/tree-vect-slp-patterns.c b/gcc/tree-vect-slp-patterns.c
index fede88923af8521ee4954c8ae27b0e589f975610..7fd79d91c6ba4ccdbf361307a6105fb7e46aa961 100644
--- a/gcc/tree-vect-slp-patterns.c
+++ b/gcc/tree-vect-slp-patterns.c
@@ -140,32 +140,32 @@  is_linear_load_p (load_permutation_t loads)
 
   unsigned load, i;
   complex_perm_kinds_t candidates[4]
-    = { PERM_EVENODD
-      , PERM_ODDEVEN
-      , PERM_ODDODD
+    = { PERM_ODDODD
       , PERM_EVENEVEN
+      , PERM_EVENODD
+      , PERM_ODDEVEN
       };
 
   int valid_patterns = 4;
-  FOR_EACH_VEC_ELT_FROM (loads, i, load, 1)
+  FOR_EACH_VEC_ELT (loads, i, load)
     {
-      if (candidates[0] != PERM_UNKNOWN && load != i)
+      if (candidates[0] != PERM_UNKNOWN && load != 1)
 	{
 	  candidates[0] = PERM_UNKNOWN;
 	  valid_patterns--;
 	}
-      if (candidates[1] != PERM_UNKNOWN
-	  && load != (i % 2 == 0 ? i + 1 : i - 1))
+      if (candidates[1] != PERM_UNKNOWN && load != 0)
 	{
 	  candidates[1] = PERM_UNKNOWN;
 	  valid_patterns--;
 	}
-      if (candidates[2] != PERM_UNKNOWN && load != 1)
+      if (candidates[2] != PERM_UNKNOWN && load != i)
 	{
 	  candidates[2] = PERM_UNKNOWN;
 	  valid_patterns--;
 	}
-      if (candidates[3] != PERM_UNKNOWN && load != 0)
+      if (candidates[3] != PERM_UNKNOWN
+	  && load != (i % 2 == 0 ? i + 1 : i - 1))
 	{
 	  candidates[3] = PERM_UNKNOWN;
 	  valid_patterns--;