nir: fix implicit fallthrough warnings

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5705>

src/compiler/nir/nir.c

@@ -1609,8 +1609,8 @@ nir_block_cf_tree_next(nir_block *block)
          return nir_if_first_else_block(if_stmt);
 
       assert(block == nir_if_last_else_block(if_stmt));
-      /* fall through */
    }
+   /* fallthrough */
 
    case nir_cf_node_loop:
       return nir_cf_node_as_block(nir_cf_node_next(parent));
@@ -1645,8 +1645,8 @@ nir_block_cf_tree_prev(nir_block *block)
          return nir_if_last_then_block(if_stmt);
 
       assert(block == nir_if_first_then_block(if_stmt));
-      /* fall through */
    }
+   /* fallthrough */
 
    case nir_cf_node_loop:
       return nir_cf_node_as_block(nir_cf_node_prev(parent));

src/compiler/nir/nir_gather_info.c

@@ -301,7 +301,7 @@ gather_intrinsic_info(nir_intrinsic_instr *instr, nir_shader *shader,
    case nir_intrinsic_demote:
    case nir_intrinsic_demote_if:
       shader->info.fs.uses_demote = true;
-   /* fallthrough: quads with helper lanes only might be discarded entirely */
+   /* fallthrough - quads with helper lanes only might be discarded entirely */
    case nir_intrinsic_discard:
    case nir_intrinsic_discard_if:
       /* Freedreno uses the discard_if intrinsic to end GS invocations that

src/compiler/nir/nir_lower_phis_to_scalar.c

@@ -109,6 +109,7 @@ is_phi_src_scalarizable(nir_phi_src *src,
          break;
       }
    }
+   /* fallthrough */
 
    default:
       /* We can't scalarize this type of instruction */

src/compiler/nir/nir_opt_gcm.c

@@ -162,6 +162,8 @@ is_src_scalarizable(nir_src *src)
       default:
          break;
       }
+
+      return false;
    }
 
    default:
@@ -199,11 +201,12 @@ gcm_pin_instructions(nir_function_impl *impl, struct gcm_state *state)
                instr->pass_flags = GCM_INSTR_SCHEDULE_EARLIER_ONLY;
                break;
 
-         case nir_op_mov:
-            if (!is_src_scalarizable(&(nir_instr_as_alu(instr)->src[0].src))) {
-               instr->pass_flags = GCM_INSTR_PINNED;
-               break;
-            }
+            case nir_op_mov:
+               if (!is_src_scalarizable(&(nir_instr_as_alu(instr)->src[0].src))) {
+                  instr->pass_flags = GCM_INSTR_PINNED;
+                  break;
+               }
+               /* fallthrough */
 
             default:
                instr->pass_flags = 0;

src/compiler/nir/nir_to_lcssa.c

@@ -178,8 +178,8 @@ instr_is_invariant(nir_instr *instr, nir_loop *loop)
       nir_intrinsic_instr *intrinsic = nir_instr_as_intrinsic(instr);
       if (!(nir_intrinsic_infos[intrinsic->intrinsic].flags & NIR_INTRINSIC_CAN_REORDER))
          return not_invariant;
-      /* fallthrough */
    }
+   /* fallthrough */
    default:
       return nir_foreach_src(instr, src_is_invariant, loop) ? invariant : not_invariant;
    }