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From: "schnetter at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/99912] Unnecessary / inefficient spilling of AVX2 ymm
 registers
Date: Tue, 27 Apr 2021 16:03:21 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99912

--- Comment #11 from Erik Schnetter <schnetter at gmail dot com> ---
The number of active local variables is likely much larger than the number =
of
registers, and I expect there to be a lot of spilling. I hope that the comp=
iler
is clever about changing the order in which expressions are evaluated to re=
duce
spilling as much as possible.

Because the loop is so large, I split it into two, each calculating about h=
alf
of the output variables. The code here looks at one of the loops. To simpli=
fy
the code, each loop still loads all variables (via masked loads), but may n=
ot
use all of them. The unused masked loads do not surprise me per se, but I
expect the compiler to remove them.=