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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/108360] [13 Regression] Dead Code Elimination Regression at -Os since r13-2048-g418b71c0d535bf
Date: Tue, 10 Jan 2023 17:45:54 +0000 [thread overview]
Message-ID: <bug-108360-4-C9zNYV05O1@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108360-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108360
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The first difference with r13-2048 is during fre3:
@@ -210,7 +210,7 @@ marking outgoing edge 6 -> 1 executable
RPO iteration over 5 blocks visited 5 blocks in total discovering 5 executable
blocks iterating 1.0 times, a block was visited max. 1 times
RPO tracked 25 values available at 18 locations and 25 lattice elements
Replaced (int) _6 with _7 in all uses of _24 = (int) _6;
-gimple_simplified to if (_6 == 0)
+gimple_simplified to if (_22 < 0)
Replaced (short int) _6 with h_23 in all uses of _25 = (short int) _6;
Removing dead stmt _25 = (short int) _6;
Removing dead stmt _24 = (int) _6;
@@ -259,7 +259,7 @@ int main ()
_7 = (int) _6;
# RANGE [irange] short int [-INF, +INF] NONZERO 0x10
h_23 = (short int) _6;
- if (_6 == 0)
+ if (_22 < 0)
goto <bb 3>; [50.00%]
else
goto <bb 4>; [50.00%]
Given:
_3 = _22 >= 0;
_4 = (char) _3;
f.5_5 = (unsigned char) _3;
_6 = f.5_5 << 4;
h_23 = (short int) _6;
and range of f.5_5 being [0, 1] that change is certainly correct.
next prev parent reply other threads:[~2023-01-10 17:45 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-10 13:10 [Bug tree-optimization/108360] New: Dead Code Elimination Regression at -Os (trunk vs. 12.2.0) yann at ywg dot ch
2023-01-10 14:48 ` [Bug tree-optimization/108360] [13 Regression] Dead Code Elimination Regression at -Os since r13-2048-g418b71c0d535bf marxin at gcc dot gnu.org
2023-01-10 17:00 ` jakub at gcc dot gnu.org
2023-01-10 17:32 ` jakub at gcc dot gnu.org
2023-01-10 17:45 ` jakub at gcc dot gnu.org [this message]
2023-01-10 19:18 ` amacleod at redhat dot com
2023-01-10 19:26 ` amacleod at redhat dot com
2023-01-10 19:28 ` amacleod at redhat dot com
2023-03-27 11:37 ` rguenth at gcc dot gnu.org
2023-04-08 14:37 ` law at gcc dot gnu.org
2023-04-26 6:57 ` [Bug tree-optimization/108360] [13/14 " rguenth at gcc dot gnu.org
2023-07-27 9:25 ` rguenth at gcc dot gnu.org
2023-08-07 8:53 ` pinskia at gcc dot gnu.org
2023-08-09 1:25 ` pinskia at gcc dot gnu.org
2024-05-21 9:13 ` [Bug tree-optimization/108360] [13/14/15 " jakub at gcc dot gnu.org
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