Some hardware doesn't support subgroup shuffle, and on such hardware it makes no sense to lower quad broadcasts to shuffle. Instead, let's lower them to four const quad broadcasts, paired with bcsel instructions.
ec16535b493 nir: Add ability to lower non-const quad broadcasts to const ones.
src/compiler/nir/nir.h | 1 +
src/compiler/nir/nir_lower_subgroups.c | 42 +++++++++++++++++++++++++++++++++-
2 files changed, 42 insertions(+), 1 deletion(-)