To clarify: this bug affects GCC8 and up with the following flags:

CFLAGS="-O3 -march=armv8.1-a+sve"

Test case can be found here: https://godbolt.org/z/4E51ETMfa or in the
GCC ticket.

To confirm the fix use Graviton4 (or another 128-bit SVE vector CPU).

The test will either print:
    PASS: got 0x00bbbbbb 0x00aaaaaa as expected
or
    ERROR: expected 0x00bbbbbb 0x00aaaaaa but got 0x00bbbbbb 0xaaaaaaaa

GCC has fixed it in the branches for gcc-12 and up, and those fixes will
be in the next GCC release, but since LTS 2004 uses gcc-9 and LTS 2204
uses gcc-11, fixes to those versions will need to be manually backported
by Canonical or risk emitting incorrect code.

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https://bugs.launchpad.net/bugs/2101084

Title:
  GCC produces wrong code for arm64+sve in some cases

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