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From: "elrodc at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/112824] Stack spills and vector splitting
 with vector builtins
Date: Sat, 02 Dec 2023 13:20:46 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D112824

--- Comment #1 from Chris Elrod <elrodc at gmail dot com> ---
Here I have added a godbolt example where I manually unroll the array, where
GCC generates excellent code https://godbolt.org/z/sd4bhGW7e
I'm not sure it is 100% optimal, but with an inner Dual size of `7`, on
Skylake-X it is 38 uops for unrolled GCC with separate struct fields, vs 49
uops for Clang, vs 67 for GCC with arrays.
uica expects <14 clock cycles for the manually unrolled vs >23 for the array
version.

My experience so far with expression templates has born this out: compilers
seem to struggle with peeling away abstractions.=