nir: Add a base const_index to shared atomic intrinsics.
nir: Add a base const_index to shared atomic intrinsics.

Commit 52e75dcb8c04c0dde989970c4c587cbe8313f7cf made nir_lower_io
start using nir_intrinsic_set_base instead of writing const_index[0]
directly.  However, those intrinsics apparently don't /have/ a base,
so this caused assert failures.

However, the old code was happily setting non-existent const_index
fields, so it was pretty bogus too.

Jason pointed out that load_shared and store_shared have a base,
and that the i965 driver uses that field.  So presumably atomics
should have one as well, so that loads/stores/atomics all refer
to variables with consistent addressing.

Cc: "12.0" <59f39c0db42d4479a46b02d4d2bc11120e37bb44@lists.freedesktop.org>
Signed-off-by: Kenneth Graunke <bd2562f754ec92342f93f61c25d731e290a2ffa8@whitecape.org>
Reviewed-by: Timothy Arceri <5dd83789ef3714029244367ba1ca09f1d7627408@collabora.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler