nir: Remove the const_offset from nir_tex_instr

When NIR was originally drafted, there was no easy way to determine if
something was constant or not.  The result was that we had lots of
special-casing for constant values such as this.  Now that load_const
instructions are SSA-only, it's really easy to find constants and this
isn't really needed anymore.

Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Rob Clark <robclark@gmail.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
index ca6a9de..74ec4f0 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
@@ -1657,6 +1657,7 @@ vec4_visitor::nir_emit_texture(nir_tex_instr *instr)
    dst_reg dest = get_nir_dest(instr->dest, instr->dest_type);
 
    /* Load the texture operation sources */
+   uint32_t constant_offset = 0;
    for (unsigned i = 0; i < instr->num_srcs; i++) {
       switch (instr->src[i].src_type) {
       case nir_tex_src_comparitor:
@@ -1713,9 +1714,17 @@ vec4_visitor::nir_emit_texture(nir_tex_instr *instr)
          break;
       }
 
-      case nir_tex_src_offset:
-         offset_value = get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_D, 2);
+      case nir_tex_src_offset: {
+         nir_const_value *const_offset =
+            nir_src_as_const_value(instr->src[i].src);
+         if (const_offset) {
+            constant_offset = brw_texture_offset(const_offset->i, 3);
+         } else {
+            offset_value =
+               get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_D, 2);
+         }
          break;
+      }
 
       case nir_tex_src_texture_offset: {
          /* The highest texture which may be used by this operation is
@@ -1771,14 +1780,6 @@ vec4_visitor::nir_emit_texture(nir_tex_instr *instr)
       }
    }
 
-   uint32_t constant_offset = 0;
-   for (unsigned i = 0; i < 3; i++) {
-      if (instr->const_offset[i] != 0) {
-         constant_offset = brw_texture_offset(instr->const_offset, 3);
-         break;
-      }
-   }
-
    /* Stuff the channel select bits in the top of the texture offset */
    if (instr->op == nir_texop_tg4) {
       if (instr->component == 1 &&