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From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/99919] [9/10/11 Regression] bogus -Wmaybe-uninitialized with a _Bool bit-field
Date: Mon, 05 Apr 2021 20:51:47 +0000 [thread overview]
Message-ID: <bug-99919-4-IljzjY2Y3u@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-99919-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99919
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Blocks| |99918
--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
The IL below shows there is enough information in the IL for the warning to
determine that x_5 is never read from.
void g (struct B b)
{
_Bool b$j;
_Bool b$i;
_Bool x;
unsigned char _1;
unsigned char _2;
unsigned char _3;
unsigned char _4;
<bb 2> [local count: 1073741824]:
b$i_11 = b.i;
_1 = VIEW_CONVERT_EXPR<unsigned char>(b);
_2 = _1 & 1;
if (_2 != 0)
goto <bb 4>; [50.00%]
else
goto <bb 3>; [50.00%]
<bb 3> [local count: 536870912]:
<bb 4> [local count: 1073741824]:
# x_5 = PHI <x_8(D)(2), b$i_11(3)>
# b$j_10 = PHI <0(2), b$i_11(3)>
b.j = b$j_10;
_3 = VIEW_CONVERT_EXPR<unsigned char>(b);
_4 = _3 & 2;
if (_4 != 0)
goto <bb 5>; [50.00%]
else
goto <bb 6>; [50.00%]
<bb 5> [local count: 536870913]:
z = x_5;
<bb 6> [local count: 1073741824]:
return;
}
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99918
[Bug 99918] [9/10/11 Regression] suboptimal code for bool bitfield tests
next prev parent reply other threads:[~2021-04-05 20:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-05 20:29 [Bug tree-optimization/99919] New: " msebor at gcc dot gnu.org
2021-04-05 20:51 ` msebor at gcc dot gnu.org [this message]
2021-04-06 8:39 ` [Bug tree-optimization/99919] " rguenth at gcc dot gnu.org
2021-04-08 14:22 ` rguenth at gcc dot gnu.org
2021-06-01 8:20 ` [Bug tree-optimization/99919] [9/10/11/12 " rguenth at gcc dot gnu.org
2021-11-30 11:58 ` aldyh at gcc dot gnu.org
2021-11-30 12:06 ` pinskia at gcc dot gnu.org
2021-11-30 14:22 ` aldyh at gcc dot gnu.org
2022-12-08 9:25 ` [Bug tree-optimization/99919] [10/11/12/13 " rguenth at gcc dot gnu.org
2022-12-08 10:47 ` rguenth at gcc dot gnu.org
2023-04-26 6:55 ` [Bug tree-optimization/99919] [10/11/12/13/14 " rguenth at gcc dot gnu.org
2023-07-27 9:22 ` [Bug tree-optimization/99919] [11/12/13/14 " rguenth at gcc dot gnu.org
2023-12-15 13:33 ` rguenth at gcc dot gnu.org
2024-05-21 9:10 ` [Bug tree-optimization/99919] [11/12/13/14/15 " jakub at gcc dot gnu.org
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