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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/98845] [8/9/10/11 Regression] ICE: SSA corruption (Unable to coalesce ssa_names 2 and 23 which are marked as MUST COALESCE.) since r6-528-g465770e43996a132
Date: Wed, 27 Jan 2021 08:54:11 +0000 [thread overview]
Message-ID: <bug-98845-4-rzDth1bSvw@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-98845-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98845
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
+find_duplicates: <bb 6> duplicate of <bb 20>
+Removing basic block 20
@@ -170,7 +180,7 @@
<bb 17> [local count: 3614577]:
goto <bb 13>; [100.00%]
- <bb 6> [local count: 7016531]:
+ <bb 6> [local count: 8742389]:
p_218_24 = p_217_23(D)(ab);
p_217_32 = p_217_23(D)(ab);
goto <bb 13>; [100.00%]
@@ -213,12 +223,10 @@
if (p_218_8 != 0)
goto <bb 19>; [83.51%]
else
- goto <bb 20>; [16.49%]
-
- <bb 20> [local count: 1725858]:
+ goto <bb 6>; [16.49%]
<bb 13> [local count: 12356965]:
- # _9 = PHI <1(17), 0(20), 0(6)>
+ # _9 = PHI <1(17), 0(6)>
return _9;
but that makes _23(D) live on the path from bb 12 to bb 13. The issue here
is that _23 and _32 are unused but their RHS is still accounted for during
LIVE problem solving but they are ignored during VN and by tail-merging
which just looks at BB side-effects.
So the testcase is really an artifact of -fno-tree-dce.
One could argue that tail merging should treat a use of abnormals as
side-effect but I think that won't play well with its structure.
next prev parent reply other threads:[~2021-01-27 8:54 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-27 4:33 [Bug tree-optimization/98845] New: [8/9/10 Regression] ICE: SSA corruption (Unable to coalesce ssa_names 2 and 23 which are marked as MUST COALESCE.) asolokha at gmx dot com
2021-01-27 7:57 ` [Bug tree-optimization/98845] [8/9/10/11 " rguenth at gcc dot gnu.org
2021-01-27 8:26 ` [Bug tree-optimization/98845] [8/9/10/11 Regression] ICE: SSA corruption (Unable to coalesce ssa_names 2 and 23 which are marked as MUST COALESCE.) since r6-528-g465770e43996a132 marxin at gcc dot gnu.org
2021-01-27 8:39 ` rguenth at gcc dot gnu.org
2021-01-27 8:54 ` rguenth at gcc dot gnu.org [this message]
2021-05-14 9:54 ` [Bug tree-optimization/98845] [9/10/11/12 " jakub at gcc dot gnu.org
2021-05-31 4:59 ` asolokha at gmx dot com
2021-05-31 8:34 ` marxin at gcc dot gnu.org
2021-05-31 8:50 ` [Bug tree-optimization/98845] [9/10/11 " rguenther at suse dot de
2021-06-01 8:19 ` rguenth at gcc dot gnu.org
2022-03-16 8:01 ` rguenth at gcc dot gnu.org
2022-03-17 4:55 ` [Bug tree-optimization/98845] [9/10/11/12 " asolokha at gmx dot com
2022-03-17 7:34 ` rguenth at gcc dot gnu.org
2022-05-27 9:44 ` [Bug tree-optimization/98845] [10/11/12/13 " rguenth at gcc dot gnu.org
2022-06-28 10:43 ` jakub at gcc dot gnu.org
2023-07-07 10:38 ` [Bug tree-optimization/98845] [11/12/13/14 " rguenth at gcc dot gnu.org
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