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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/102989] Implement C2x's n2763 (_BitInt)
Date: Tue, 18 Jul 2023 15:45:24 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102989

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #55567|0                           |1
        is obsolete|                            |

--- Comment #85 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 55572
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D55572&action=3Dedit
gcc14-bitint-wip.patch

At least the x86-64 _BitInt psABI says that the padding bits are undefined =
and
the various other psABI proposals do that as well.
Though, when looking at RTL expansion, we were doing REDUCE_BIT_FIELD after
operations, meaning that that we effectively relied on those bits at least =
for
small/middle _BitInt to be sign or zero extended.
This change tries to force sign/zero extensions when reading _BitInt from
memory, parameters etc.=