diff mbox series

tree-optimization/105629 - spaceship recognition regression

Message ID 20220523105338.0039013AA5@imap2.suse-dmz.suse.de
State Committed
Commit d918faea1217596877a35c4946500399731fbbd3
Headers
Series tree-optimization/105629 - spaceship recognition regression |

Commit Message

Richard Biener May 23, 2022, 10:53 a.m. UTC 
  With the extra GENERIC folding we now do to
(unsigned int) __v._M_value & 1 != (unsigned int) __v._M_value
we end up with a sign-extending conversion to unsigned int
rather than the sign-conversion to unsigned char we expect.
Relaxing that fixes the regression.

Bootstrapped and tested on x86_64-unknown-linux-gnu, OK?

Thanks,
Richard.

2022-05-23  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/105629
	* tree-ssa-phiopt.cc (spaceship_replacement): Allow
	a sign-extending conversion.
---
 gcc/tree-ssa-phiopt.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Jakub Jelinek May 23, 2022, 4:27 p.m. UTC | #1 
On Mon, May 23, 2022 at 12:53:37PM +0200, Richard Biener wrote:
> With the extra GENERIC folding we now do to
> (unsigned int) __v._M_value & 1 != (unsigned int) __v._M_value
> we end up with a sign-extending conversion to unsigned int
> rather than the sign-conversion to unsigned char we expect.
> Relaxing that fixes the regression.
> 
> Bootstrapped and tested on x86_64-unknown-linux-gnu, OK?
> 
> Thanks,
> Richard.
> 
> 2022-05-23  Richard Biener  <rguenther@suse.de>
> 
> 	PR tree-optimization/105629
> 	* tree-ssa-phiopt.cc (spaceship_replacement): Allow
> 	a sign-extending conversion.
> ---
>  gcc/tree-ssa-phiopt.cc | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
> index 8c9c46d41f1..e61d9736937 100644
> --- a/gcc/tree-ssa-phiopt.cc
> +++ b/gcc/tree-ssa-phiopt.cc
> @@ -2217,7 +2217,7 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
>  
>        if (!TYPE_UNSIGNED (ty2) || !INTEGRAL_TYPE_P (ty2))
>  	return false;
> -      if (TYPE_PRECISION (ty1) != TYPE_PRECISION (ty2))
> +      if (TYPE_PRECISION (ty1) > TYPE_PRECISION (ty2))
>  	return false;
>        if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig_use_lhs))
>  	return false;

LGTM, thanks.

	Jakub
diff mbox series

Patch

diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index 8c9c46d41f1..e61d9736937 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -2217,7 +2217,7 @@  spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
 
       if (!TYPE_UNSIGNED (ty2) || !INTEGRAL_TYPE_P (ty2))
 	return false;
-      if (TYPE_PRECISION (ty1) != TYPE_PRECISION (ty2))
+      if (TYPE_PRECISION (ty1) > TYPE_PRECISION (ty2))
 	return false;
       if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig_use_lhs))
 	return false;