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From: "aoliva at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug debug/103241] Odd 0 length entries in location lists
Date: Fri, 19 Nov 2021 10:18:11 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103241

--- Comment #14 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Hi, Will, Jakub, Martin,

There's nothing particularly unusual about apparently empty ranges, especia=
lly
when views are enabled, since the very point of location views is to enable
multiple states to be distinguished at the same PC.

It is a little odd that an additional location entry gets emitted for prot =
at
function entry.  I suppose inspection of gimple dumps will show some SSA
assignment apparently setting some prot version, and that we end up outputt=
ing
a new entry for it.  The difference between the two locations, one without =
and
the other with DW_OP_piece, suggests that some internal state change was
perceived between one view and the other; it might be something about
(do-nothing) promotions between the argument bindings for the prototype and=
 the
body.

We might be able to get rid of the restatement of the binding with some more
effort.=