nir: remove unused nir_io_semantics::invariant

Acked-by: Alyssa on IRC
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35256>

src/compiler/nir/nir.h

@@ -1940,7 +1940,6 @@ typedef struct nir_io_semantics {
    unsigned medium_precision : 1; /* GLSL mediump qualifier */
    unsigned per_view : 1;
    unsigned high_16bits : 1; /* whether accessing low or high half of the slot */
-   unsigned invariant : 1;   /* The variable has the invariant flag set */
    unsigned high_dvec2 : 1; /* whether accessing the high half of dvec3/dvec4 */
    /* CLIP_DISTn, LAYER, VIEWPORT, and TESS_LEVEL_* have up to 3 uses:
     * - an output consumed by the next stage
@@ -1953,6 +1952,7 @@ typedef struct nir_io_semantics {
    unsigned no_sysval_output : 1; /* whether this system value output has no
                                      effect due to current pipeline states */
    unsigned interp_explicit_strict : 1; /* preserve original vertex order */
+   unsigned _pad : 1;
 } nir_io_semantics;
 
 /* Transform feedback info for 2 outputs. nir_intrinsic_store_output contains

src/compiler/nir/nir_lower_io.c

@@ -564,7 +564,6 @@ emit_store(struct lower_io_state *state, nir_def *data,
    semantics.gs_streams = gs_streams;
    semantics.medium_precision = is_medium_precision(b->shader, var);
    semantics.per_view = var->data.per_view;
-   semantics.invariant = var->data.invariant;
 
    nir_intrinsic_set_io_semantics(store, semantics);
 

src/compiler/nir/nir_opt_vectorize_io.c

@@ -261,8 +261,6 @@ vectorize_store(nir_intrinsic_instr *chan[8], unsigned start, unsigned count,
          sem.no_sysval_output = 0;
       if (!nir_intrinsic_io_semantics(chan[i]).no_varying)
          sem.no_varying = 0;
-      if (nir_intrinsic_io_semantics(chan[i]).invariant)
-         sem.invariant = 1;
    }
 
    if (merge_low_high_16_to_32) {
@@ -272,8 +270,6 @@ vectorize_store(nir_intrinsic_instr *chan[8], unsigned start, unsigned count,
             sem.no_sysval_output = 0;
          if (!nir_intrinsic_io_semantics(chan[4 + i]).no_varying)
             sem.no_varying = 0;
-         if (nir_intrinsic_io_semantics(chan[4 + i]).invariant)
-            sem.invariant = 1;
       }
 
       /* Update the type. */

src/compiler/nir/nir_print.c

@@ -1469,9 +1469,6 @@ print_intrinsic_instr(nir_intrinsic_instr *instr, print_state *state)
          if (io.high_16bits)
             fprintf(fp, " high_16bits");
 
-         if (io.invariant)
-            fprintf(fp, " invariant");
-
          if (io.high_dvec2)
             fprintf(fp, " high_dvec2");
 

src/gallium/auxiliary/nir/nir_to_tgsi.c

@@ -708,11 +708,6 @@ ntt_output_decl(struct ntt_compile *c, nir_intrinsic_instr *instr, uint32_t *fra
       /* No driver appears to use array_id of outputs. */
       unsigned array_id = 0;
 
-      /* This bit is lost in the i/o semantics, but it's unused in in-tree
-       * drivers.
-       */
-      bool invariant = semantics.invariant;
-
       unsigned num_slots = semantics.num_slots;
       if (semantics.location == VARYING_SLOT_TESS_LEVEL_INNER ||
           semantics.location == VARYING_SLOT_TESS_LEVEL_OUTER) {
@@ -729,7 +724,7 @@ ntt_output_decl(struct ntt_compile *c, nir_intrinsic_instr *instr, uint32_t *fra
                                     usage_mask,
                                     array_id,
                                     num_slots,
-                                    invariant);
+                                    false);
    }
 
    unsigned write_mask;

src/gallium/drivers/r300/compiler/nir_to_rc.c

@@ -287,13 +287,8 @@ ntr_output_decl(struct ntr_compile *c, nir_intrinsic_instr *instr, uint32_t *fra
       /* No driver appears to use array_id of outputs. */
       unsigned array_id = 0;
 
-      /* This bit is lost in the i/o semantics, but it's unused in in-tree
-       * drivers.
-       */
-      bool invariant = semantics.invariant;
-
       out = ureg_DECL_output_layout(c->ureg, semantic_name, semantic_index, gs_streams, base,
-                                    usage_mask, array_id, semantics.num_slots, invariant);
+                                    usage_mask, array_id, semantics.num_slots, false);
    }
 
    unsigned write_mask;

src/mesa/state_tracker/st_nir_unlower_io_to_vars.c

@@ -472,7 +472,6 @@ create_vars(nir_builder *b, nir_intrinsic_instr *intr, void *opaque)
    }
 
    /* Some semantics are dependent on the instruction or component. */
-   var->data.invariant |= desc.sem.invariant;
    var->data.stream |= (desc.sem.gs_streams << (desc.component * 2));
    if (var->data.stream)
       var->data.stream |= NIR_STREAM_PACKED;