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?
2024-11-20 Jakub Jelinek <ja...@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.
--- 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
