nir: Add another index to load_uniform to specify the range read

Reviewed-by: Kristian Høgsberg <krh@bitplanet.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/compiler/nir/nir.h

@@ -965,6 +965,12 @@ typedef enum {
     */
    NIR_INTRINSIC_UCP_ID = 4,
 
+   /**
+    * The amount of data, starting from BASE, that this instruction may
+    * access.  This is used to provide bounds if the offset is not constant.
+    */
+   NIR_INTRINSIC_RANGE = 5,
+
    NIR_INTRINSIC_NUM_INDEX_FLAGS,
 
 } nir_intrinsic_index_flag;
@@ -1028,6 +1034,7 @@ INTRINSIC_IDX_ACCESSORS(write_mask, WRMASK, unsigned)
 INTRINSIC_IDX_ACCESSORS(base, BASE, int)
 INTRINSIC_IDX_ACCESSORS(stream_id, STREAM_ID, unsigned)
 INTRINSIC_IDX_ACCESSORS(ucp_id, UCP_ID, unsigned)
+INTRINSIC_IDX_ACCESSORS(range, RANGE, unsigned)
 
 /**
  * \group texture information

src/compiler/nir/nir_intrinsics.h

@@ -293,6 +293,10 @@ SYSTEM_VALUE(helper_invocation, 1, 0, xx, xx, xx)
  * of the start of the variable being loaded and and the offset source is a
  * offset into that variable.
  *
+ * Uniform load operations have a second "range" index that specifies the
+ * range (starting at base) of the data from which we are loading.  If
+ * const_index[1] == 0, then the range is unknown.
+ *
  * Some load operations such as UBO/SSBO load and per_vertex loads take an
  * additional source to specify which UBO/SSBO/vertex to load from.
  *
@@ -306,7 +310,7 @@ SYSTEM_VALUE(helper_invocation, 1, 0, xx, xx, xx)
    INTRINSIC(load_##name, srcs, ARR(1, 1, 1, 1), true, 0, 0, num_indices, idx0, idx1, idx2, flags)
 
 /* src[] = { offset }. const_index[] = { base } */
-LOAD(uniform, 1, 1, BASE, xx, xx, NIR_INTRINSIC_CAN_ELIMINATE | NIR_INTRINSIC_CAN_REORDER)
+LOAD(uniform, 1, 2, BASE, RANGE, xx, NIR_INTRINSIC_CAN_ELIMINATE | NIR_INTRINSIC_CAN_REORDER)
 /* src[] = { buffer_index, offset }. No const_index */
 LOAD(ubo, 2, 0, xx, xx, xx, NIR_INTRINSIC_CAN_ELIMINATE | NIR_INTRINSIC_CAN_REORDER)
 /* src[] = { offset }. const_index[] = { base } */

src/compiler/nir/nir_lower_io.c

@@ -277,6 +277,11 @@ nir_lower_io_block(nir_block *block, void *void_state)
          nir_intrinsic_set_base(load,
             intrin->variables[0]->var->data.driver_location);
 
+         if (load->intrinsic == nir_intrinsic_load_uniform) {
+            nir_intrinsic_set_range(load,
+               state->type_size(intrin->variables[0]->var->type));
+         }
+
          if (per_vertex)
             load->src[0] = nir_src_for_ssa(vertex_index);
 

src/compiler/nir/nir_print.c

@@ -517,6 +517,7 @@ print_intrinsic_instr(nir_intrinsic_instr *instr, print_state *state)
       [NIR_INTRINSIC_WRMASK] = "wrmask",
       [NIR_INTRINSIC_STREAM_ID] = "stream-id",
       [NIR_INTRINSIC_UCP_ID] = "ucp-id",
+      [NIR_INTRINSIC_RANGE] = "range",
    };
    for (unsigned idx = 1; idx < NIR_INTRINSIC_NUM_INDEX_FLAGS; idx++) {
       if (!info->index_map[idx])