[PowerPC] Altivec doesn't support NaN return NaN behavior

[Link4Electronics]

Hello,

Running Linux 6.17.7 PPC64 big-endian on a Power Mac G5, CPU POWER4 970MP, LLVM 21.1.4
When trying to run lp_test_arit from mesa project, it shows:

altivec doesn't support nan return nan behavior

round.v1(-0.5): ref = -0, out = -1, precision = -inf bits, FAIL

round.v1(0.5): ref = 0, out = 1, precision = -inf bits, FAIL

would it be related to float->int conversion when rounding?

Best regards,
Link.

[hstk30-hw]

You'd better give a simple reproducer.

[llvmbot]

@llvm/issue-subscribers-backend-powerpc

Author: None (Link4Electronics)

Hello,

Running Linux 6.17.7 PPC64 big-endian on a Power Mac G5, CPU POWER4 970MP, LLVM 21.1.4
When trying to run lp_test_arit from mesa project, it shows:

altivec doesn't support nan return nan behavior

round.v1(-0.5): ref = -0, out = -1, precision = -inf bits, FAIL

round.v1(0.5): ref = 0, out = 1, precision = -inf bits, FAIL

would it be related to float->int conversion when rounding?

Best regards,
Link.

[Link4Electronics]

git clone --recursive https://gitlab.freedesktop.org/mesa/mesa.git

With all it's dependencies installed,
meson setup builddir/ -D galium-drivers=llvmpipe -D build-tests=true

meson compile -C /builddir

inside builddir/src/gallium/drivers/llvmpipe will be lp_test_arit, when trying to run it, gives the error:

altivec doesn't support nan return nan behavior

round.v1(-0.5): ref = -0, out = -1, precision = -inf bits, FAIL

round.v1(0.5): ref = 0, out = 1, precision = -inf bits, FAIL