On Wed, 20 Nov 2024, Jakub Jelinek wrote:
> Hi!
>
> When working on the PR117612 fix, I've noticed a pasto in
> tree-ssa-phiopt.cc (spaceship_replacement).
> The code is
> if (absu_hwi (tree_to_shwi (arg2)) != 1)
> return false;
> if (e1->flags & EDGE_TRUE_VALUE)
> {
> if (tree_to_shwi (arg0) != 2
> || absu_hwi (tree_to_shwi (arg1)) != 1
> || wi::to_widest (arg1) == wi::to_widest (arg2))
> return false;
> }
> else if (tree_to_shwi (arg1) != 2
> || absu_hwi (tree_to_shwi (arg0)) != 1
> || wi::to_widest (arg0) == wi::to_widest (arg1))
> return false;
> where arg{0,1,2,3} are PHI args and wants to ensure that if e1 is a
> true edge, then arg0 is 2 and one of arg{1,2} is -1 and one is 1,
> otherwise arg1 is 2 and one of arg{0,2} is -1 and one is 1.
> But due to pasto in the latte case doesn't verify that arg0
> is different from arg2, it could be both -1 or both 1 and we wouldn't
> punt. The wi::to_widest (arg0) == wi::to_widest (arg1) test
> is always false when we've made sure in the earlier conditions that
> arg1 is 2 and arg0 is -1 or 1, so never 2.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
> 2024-11-20 Jakub Jelinek <[email protected]>
>
> PR tree-optimization/94589
> PR tree-optimization/117612
> * tree-ssa-phiopt.cc (spaceship_replacement): Fix up
> a pasto in check when arg1 is 2.
>
> --- gcc/tree-ssa-phiopt.cc.jj 2024-11-19 20:30:56.311541135 +0100
> +++ gcc/tree-ssa-phiopt.cc 2024-11-20 12:37:41.594315207 +0100
> @@ -2690,7 +2692,7 @@ spaceship_replacement (basic_block cond_
> }
> else if (tree_to_shwi (arg1) != 2
> || absu_hwi (tree_to_shwi (arg0)) != 1
> - || wi::to_widest (arg0) == wi::to_widest (arg1))
> + || wi::to_widest (arg0) == wi::to_widest (arg2))
> return false;
> switch (cmp2)
> {
>
> Jakub
>
>
--
Richard Biener <[email protected]>
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