nir: Make load_const SSA-only

As it was, we weren't ever using load_const in a non-SSA way.  This allows
us to substantially simplify the load_const instruction.  If we ever need a
non-SSA constant load, we can do a load_const and an imov.

Reviewed-by: Connor Abbott <[email protected]>

2 files changed, 3 insertions, 26 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index e589c9646b5..ad3d9866d53 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -583,7 +583,6 @@ public:
    void nir_emit_alu(nir_alu_instr *instr);
    void nir_emit_intrinsic(nir_intrinsic_instr *instr);
    void nir_emit_texture(nir_tex_instr *instr);
-   void nir_emit_load_const(nir_load_const_instr *instr);
    void nir_emit_jump(nir_jump_instr *instr);
    fs_reg get_nir_src(nir_src src);
    fs_reg get_nir_alu_src(nir_alu_instr *instr, unsigned src);
diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index c218b722f8d..4c08cfdb6ad 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -392,7 +392,9 @@ fs_visitor::nir_emit_instr(nir_instr *instr)
       break;
 
    case nir_instr_type_load_const:
-      nir_emit_load_const(nir_instr_as_load_const(instr));
+      /* We can hit these, but we do nothing now and use them as
+       * immediates later.
+       */
       break;
 
    case nir_instr_type_jump:
@@ -1702,30 +1704,6 @@ fs_visitor::nir_emit_texture(nir_tex_instr *instr)
 }
 
 void
-fs_visitor::nir_emit_load_const(nir_load_const_instr *instr)
-{
-   /* Bail on SSA constant loads.  These are used for immediates. */
-   if (instr->dest.is_ssa)
-      return;
-
-   fs_reg dest = get_nir_dest(instr->dest);
-   dest.type = BRW_REGISTER_TYPE_UD;
-   if (instr->array_elems == 0) {
-      for (unsigned i = 0; i < instr->num_components; i++) {
-         emit(MOV(dest, fs_reg(instr->value.u[i])));
-         dest.reg_offset++;
-      }
-   } else {
-      for (unsigned i = 0; i < instr->array_elems; i++) {
-         for (unsigned j = 0; j < instr->num_components; j++) {
-            emit(MOV(dest, fs_reg(instr->array[i].u[j])));
-            dest.reg_offset++;
-         }
-      }
-   }
-}
-
-void
 fs_visitor::nir_emit_jump(nir_jump_instr *instr)
 {
    switch (instr->type) {