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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/99565] [11 Regression] Bogus identical branches warning
 when returning references to union members
Date: Tue, 16 Mar 2021 13:55:27 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99565

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 50398
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D50398&action=3Dedit
gcc11-pr99565.patch

If we don't want to warn in this case (I guess pedantically in both C and C=
++
it matters which exact union member is used even when it has the same type,
because only one of them can be active, but practically the compiler will t=
reat
them the same anyway and so they are effectively the same), perhaps we could
revert Honza's change for OEP_LEXICOGRAPHIC and use that mode for the COND_=
EXPR
warnings (where previously it was used just for then/else variant).
But, apparently then we warn for some reason twice on:
int a;

void
foo (bool x)
{
  x ? ++a : ++a;
}
instead of once.  Or add some new OEP_ flag that would be used for
-Wduplicated-branches?=