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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/108355] [13 Regression] Dead Code Elimination
 Regression at -O2 since r13-2772-g9baee6181b4e42
Date: Wed, 11 Jan 2023 14:46:55 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108355

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Basically get_ref_base_and_extent trusts TYPE_SIZE of the array operand of =
an
ARRAY_REF (it would also use range info on an SSA name index, but we'd expe=
ct
a singleton to be propagated there already).  In principle that would be
a general "folding" trick we can apply to more consistently handle this
situation across passes.  gimplification might be the "nicest" place to
handle this, OTOH inlining / CCP might turn VLAs into [1] as well.=