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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/103857] implement ternary without jump (and
 comparison)
Date: Wed, 29 Dec 2021 13:03:32 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103857

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

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

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I don't think that's equivalent.  For a[i] equal to b it will be and simila=
rly
it will be for a[i] equal to c, but not for all the other values.
E.g. 13 =3D=3D 42 ? 24 : 42 is 42, but 13 ^ (24 ^ 42) is 63.
So, we could do this only if something assures us that a[i] only has 2 poss=
ible
values, either equal to b or to c.  So that would rule out non-constant b o=
r c,
perhaps it could be done if value range is two adjacent constants equal to b
and c, or perhaps if the non-zero bits has a single bit and one of b or c i=
s 0
and the other one is that non-zero bitmask of the other comparison operand.=