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From: "munroesj at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/100085] Bad code for union transfer from __float128 to
 vector types
Date: Thu, 10 Jun 2021 15:00:50 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D100085

--- Comment #13 from Steven Munroe <munroesj at gcc dot gnu.org> ---
"We want to use plain TImode instead of V1TImode on newer cpus."

Actually I disagree. We have vector __int128 in the ABI and with POWER10 a
complete set arithmetic operations for 128-bit in VRs.

Also this issue is not restricted to TImode. It also effects _Float128
(KFmode), _ibm128 (TFmode) and Libmvec for vector float/double. The proper =
and
optimum handling of these "union transfers" has been broken in GCC for year=
s.

And I have grave reservations about the vague plans of small/fringe minorit=
y to
subset the PowerISA for their convenience.=