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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/113441] [14 Regression] Fail to fold the last
 element with multiple loop since g:2efe3a7de0107618397264017fb045f237764cc7
Date: Tue, 27 Feb 2024 08:08:48 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113441

--- Comment #30 from Richard Biener <rguenth at gcc dot gnu.org> ---
The x86 and "emulation" paths handle narrowing/widening during code generat=
ion
(but yes, the IFN path doesn't).  A fix would be to do similar as for the
gs_info.decl case in vectorizable_load/store and handle select cases of
widening/narrowing (2x) and adjust vect_check_gather_scatter accordingly.
That might be against the spirit of how the IFN support was laid out
(possibly to be "cleaner"), but I don't see a good way to avoid the very
premature (during pattern selection) load/store vectorization choosing for
the cases there are multiple possibilities as seen here.=