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phiopt: Fix a pasto in spaceship_replacement [PR117612]

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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.

2024-11-21  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/94589
	PR tree-optimization/117612
	* tree-ssa-phiopt.cc (spaceship_replacement): Fix up
	a pasto in check when arg1 is 2.
This commit is contained in:
Jakub Jelinek 2024-11-21 09:38:01 +01:00 committed by Jakub Jelinek
parent 7272e09c9b
commit ca7430f145
1 changed files with 1 additions and 1 deletions
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gcc/tree-ssa-phiopt.cc
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@ -2690,7 +2690,7 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
}
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)
{