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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/20514] hoisting of label out of jumptable
 would take place at cse, should happen at trees
Date: Sat, 05 Aug 2023 03:09:54 +0000
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X-Bugzilla-Type: changed
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 4.0.0
X-Bugzilla-Keywords: missed-optimization, TREE
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X-Bugzilla-Who: pinskia at gcc dot gnu.org
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Message-ID: <bug-20514-4-zwuk6ZoEME@http.gcc.gnu.org/bugzilla/>
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D20514

--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
in GCC 13+ we get now (for the testcase in comment #0) at -O3:
```
  <bb 4> [local count: 452984831]:
  # i_lsm.4_2 =3D PHI <i_lsm.4_11(3), 4(4)>
  if (i_lsm.4_2 =3D=3D 5)
    goto <bb 4>; [25.00%]
  else
    goto <bb 5>; [75.00%]

  <bb 5> [local count: 452984832]:
  goto <bb 5>; [100.00%]
```
This is an infinite no matter which branch is taken ...
Coming in we get either `3->4->4->5` or `3->4->5` no matter what we end up =
in 5
always.=