nir/lower_subgroups: Lower ballot intrinsics to the specified bit size

Ballot intrinsics return a bitfield of subgroups.  In GLSL and some
SPIR-V extensions, they return a uint64_t.  In SPV_KHR_shader_ballot,
they return a uvec4.  Also, some back-ends would rather pass around
32-bit values because it's easier than messing with 64-bit all the time.
To solve this mess, we make nir_lower_subgroups take a new parameter
called ballot_bit_size and it lowers whichever thing it gets in from the
source language (uint64_t or uvec4) to a scalar with the specified
number of bits.  This replaces a chunk of the old lowering code.

Reviewed-by: Lionel Landwerlin <[email protected]>
Reviewed-by: Iago Toral Quiroga <[email protected]>

1 files changed, 0 insertions, 18 deletions

diff --git a/src/compiler/nir/nir_opt_intrinsics.c b/src/compiler/nir/nir_opt_intrinsics.c
index 98c8b1a01e8..eb394af0c10 100644
--- a/src/compiler/nir/nir_opt_intrinsics.c
+++ b/src/compiler/nir/nir_opt_intrinsics.c
@@ -54,24 +54,6 @@ opt_intrinsics_impl(nir_function_impl *impl)
             if (nir_src_as_const_value(intrin->src[0]))
                replacement = nir_imm_int(&b, NIR_TRUE);
             break;
-         case nir_intrinsic_ballot: {
-            assert(b.shader->options->max_subgroup_size != 0);
-            if (b.shader->options->max_subgroup_size > 32 ||
-                intrin->dest.ssa.bit_size <= 32)
-               continue;
-
-            nir_intrinsic_instr *ballot =
-               nir_intrinsic_instr_create(b.shader, nir_intrinsic_ballot);
-            nir_ssa_dest_init(&ballot->instr, &ballot->dest, 1, 32, NULL);
-            nir_src_copy(&ballot->src[0], &intrin->src[0], ballot);
-
-            nir_builder_instr_insert(&b, &ballot->instr);
-
-            replacement = nir_pack_64_2x32_split(&b,
-                                                 &ballot->dest.ssa,
-                                                 nir_imm_int(&b, 0));
-            break;
-         }
          default:
             break;
          }