nir/copy_prop_vars: Get modes directly from derefs

Instead of going all the way back to the variable, just look at the
deref.  The modes are guaranteed to be the same by nir_validate whenever
the variable can be found.  This fixes apply_barrier_for_modes for
derefs that don't have an accessible variable.

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>

diff --git a/src/compiler/nir/nir_opt_copy_prop_vars.c b/src/compiler/nir/nir_opt_copy_prop_vars.c
index 48070cd5e314c2b28bd1ed22a2611b9502b889fc..a540e01529c297db3e49e855fa014d929b9ada0a 100644 (file)
--- a/src/compiler/nir/nir_opt_copy_prop_vars.c
+++ b/src/compiler/nir/nir_opt_copy_prop_vars.c
@@ -337,12 +337,8 @@ apply_barrier_for_modes(struct util_dynarray *copies,
                         nir_variable_mode modes)
 {
    util_dynarray_foreach_reverse(copies, struct copy_entry, iter) {
-      nir_variable *dst_var = nir_deref_instr_get_variable(iter->dst);
-      nir_variable *src_var = iter->src.is_ssa ? NULL :
-         nir_deref_instr_get_variable(iter->src.deref);
-
-      if ((dst_var->data.mode & modes) ||
-          (src_var && (src_var->data.mode & modes)))
+      if ((iter->dst->mode & modes) ||
+          (!iter->src.is_ssa && (iter->src.deref->mode & modes)))
          copy_entry_remove(copies, iter);
    }
 }