radeonsi: emit TGSI_OPCODE_READ_*

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 1bf5810..541dc7b 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -5230,6 +5230,39 @@ static void ballot_emit(
        emit_data->output[1] = LLVMBuildExtractElement(builder, tmp, ctx->i32_1, "");
 }
 
+static void read_invoc_fetch_args(
+       struct lp_build_tgsi_context *bld_base,
+       struct lp_build_emit_data *emit_data)
+{
+       emit_data->args[0] = lp_build_emit_fetch(bld_base, emit_data->inst,
+                                                0, emit_data->src_chan);
+
+       /* Always read the source invocation (= lane) from the X channel. */
+       emit_data->args[1] = lp_build_emit_fetch(bld_base, emit_data->inst,
+                                                1, TGSI_CHAN_X);
+       emit_data->arg_count = 2;
+}
+
+static void read_lane_emit(
+       const struct lp_build_tgsi_action *action,
+       struct lp_build_tgsi_context *bld_base,
+       struct lp_build_emit_data *emit_data)
+{
+       struct si_shader_context *ctx = si_shader_context(bld_base);
+       LLVMBuilderRef builder = ctx->gallivm.builder;
+
+       for (unsigned i = 0; i < emit_data->arg_count; ++i) {
+               emit_data->args[i] = LLVMBuildBitCast(builder, emit_data->args[i],
+                                                     ctx->i32, "");
+       }
+
+       emit_data->output[emit_data->chan] =
+               ac_build_intrinsic(&ctx->ac, action->intr_name,
+                                  ctx->i32, emit_data->args, emit_data->arg_count,
+                                  AC_FUNC_ATTR_READNONE |
+                                  AC_FUNC_ATTR_CONVERGENT);
+}
+
 static unsigned si_llvm_get_stream(struct lp_build_tgsi_context *bld_base,
                                       struct lp_build_emit_data *emit_data)
 {
@@ -6679,6 +6712,11 @@ static void si_init_shader_ctx(struct si_shader_context *ctx,
        bld_base->op_actions[TGSI_OPCODE_VOTE_ANY].emit = vote_any_emit;
        bld_base->op_actions[TGSI_OPCODE_VOTE_EQ].emit = vote_eq_emit;
        bld_base->op_actions[TGSI_OPCODE_BALLOT].emit = ballot_emit;
+       bld_base->op_actions[TGSI_OPCODE_READ_FIRST].intr_name = "llvm.amdgcn.readfirstlane";
+       bld_base->op_actions[TGSI_OPCODE_READ_FIRST].emit = read_lane_emit;
+       bld_base->op_actions[TGSI_OPCODE_READ_INVOC].intr_name = "llvm.amdgcn.readlane";
+       bld_base->op_actions[TGSI_OPCODE_READ_INVOC].fetch_args = read_invoc_fetch_args;
+       bld_base->op_actions[TGSI_OPCODE_READ_INVOC].emit = read_lane_emit;
 
        bld_base->op_actions[TGSI_OPCODE_EMIT].emit = si_llvm_emit_vertex;
        bld_base->op_actions[TGSI_OPCODE_ENDPRIM].emit = si_llvm_emit_primitive;