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 <rguent...@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
