Bug#1022576: mesa causes FTBFS and autopkgtest regressions on 32bit ARM due to LLVM ERROR

[Adrian Bunk]

Source: mesa
Version: 22.2.1-1
Severity: serious
Tags: ftbfs
X-Debbugs-Cc: LLVM Packaging Team <pkg-llvm-team at lists.alioth.debian.org>
Control: affects -1 src:clutter-1.0 src:gtk4 src:mutter src:mrpt src:lomiri-settings-components

https://buildd.debian.org/status/package.php?p=mutter

...
# Start of pipeline tests
LLVM ERROR: Cannot select: 0x1300f80: v4i32 = ARMISD::VCMPZ 0x1301c70, Constant:i32<2>
  0x1301c70: v4i32,ch = ARMISD::VLD1DUP<(load (s32) from %ir.212)> 0xdf9afc, 0x131c538:1, Constant:i32<4>
    0x131c538: i32,i32,ch = load<(load (s32) from %ir.209, align 8), <post-inc>> 0xdf9afc, 0x12fb7e0, Constant:i32<64>
      0x12fb7e0: i32,ch = CopyFromReg 0xdf9afc, Register:i32 %23
        0x12e99c0: i32 = Register %23
      0x131a9a8: i32 = Constant<64>
    0x1319fd0: i32 = Constant<4>
  0x131a2e8: i32 = Constant<2>
In function: fs_variant_partial
...


Some discussion is in
https://bugs.launchpad.net/ubuntu/+source/llvm-toolchain-15/+bug/1993800

Temporarily going back to LLVM 14 might be a possible
short-term workaround (untested).