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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/112402] [11/12/13/14 Regression] Path
 splitting causes if-conversion miss
Date: Tue, 07 Nov 2023 03:27:02 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D112402

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The orginal threads about patch splitting:
https://gcc.gnu.org/legacy-ml/gcc/2015-03/msg00057.html
https://gcc.gnu.org/pipermail/gcc/2015-May/217495.html

> or axe path splitting or move it to RTL
Jeff had a similar idea back in 2016 (I would assume while he was looking i=
nto
PR 68541):
https://gcc.gnu.org/pipermail/gcc-patches/2016-February/441651.html :
```
And if that's the case, then we may really be looking at something that=20
belongs at the RTL level rather than at the tree/gimple level.  Sadly,=20
it's harder to do things like duplicate blocks at the RTL level.
```
and also mentioned in (which was the heustrics added to fix PR 68541):
https://gcc.gnu.org/pipermail/gcc-patches/2016-February/441841.html

Maybe this is something for GCC 15 ... to move to this to RTL right during =
the
loop optimization phase after pass_rtl_doloop. There is still a CSE and DSE=
/DCE
passes afterwards too.=