Mesa (master): nir/opt_access: rename can_reorder() and set ACCESS_NON_WRITEABLE in it

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Module: Mesa
Branch: master
Commit: d587dc32f37f43aa277516a69ad673db8441ffb8
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=d587dc32f37f43aa277516a69ad673db8441ffb8

Author: Rhys Perry <pendingchaos02 at gmail.com>
Date:   Tue Aug 25 14:30:52 2020 +0100

nir/opt_access: rename can_reorder() and set ACCESS_NON_WRITEABLE in it

Signed-off-by: Rhys Perry <pendingchaos02 at gmail.com>
Reviewed-by: Connor Abbott <cwabbott0 at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6483>

---

 src/compiler/nir/nir_opt_access.c | 94 ++++++++++++---------------------------
 1 file changed, 28 insertions(+), 66 deletions(-)

diff --git a/src/compiler/nir/nir_opt_access.c b/src/compiler/nir/nir_opt_access.c
index d1701686ddc..4588b4cec0f 100644
--- a/src/compiler/nir/nir_opt_access.c
+++ b/src/compiler/nir/nir_opt_access.c
@@ -152,17 +152,27 @@ process_variable(struct access_state *state, nir_variable *var)
 }
 
 static bool
-can_reorder(struct access_state *state, enum gl_access_qualifier access,
-            bool is_buffer, bool is_ssbo)
+update_access(struct access_state *state, nir_intrinsic_instr *instr, bool is_image, bool is_buffer)
 {
-   bool is_any_written = is_buffer ? state->buffers_written :
-      state->images_written;
+   enum gl_access_qualifier access = nir_intrinsic_access(instr);
 
-   /* Can we guarantee that the underlying memory is never written? */
-   if (!is_any_written || (access & ACCESS_NON_WRITEABLE))
-      return !(access & ACCESS_VOLATILE);
+   bool is_memory_readonly = access & ACCESS_NON_WRITEABLE;
 
-   return false;
+   if (instr->intrinsic != nir_intrinsic_bindless_image_load) {
+      const nir_variable *var = nir_intrinsic_get_var(instr, 0);
+      is_memory_readonly |= var->data.access & ACCESS_NON_WRITEABLE;
+   }
+
+   is_memory_readonly |= is_buffer ? !state->buffers_written : !state->images_written;
+
+   if (is_memory_readonly)
+      access |= ACCESS_NON_WRITEABLE;
+   if (!(access & ACCESS_VOLATILE) && is_memory_readonly)
+      access |= ACCESS_CAN_REORDER;
+
+   bool progress = nir_intrinsic_access(instr) != access;
+   nir_intrinsic_set_access(instr, access);
+   return progress;
 }
 
 static bool
@@ -170,72 +180,24 @@ process_intrinsic(struct access_state *state, nir_intrinsic_instr *instr)
 {
    switch (instr->intrinsic) {
    case nir_intrinsic_bindless_image_load:
-      if (nir_intrinsic_access(instr) & ACCESS_CAN_REORDER)
-         return false;
-
-      /* We have less information about bindless intrinsics, since we can't
-       * always trace uses back to the variable. Don't try and infer if it's
-       * read-only, unless there are no image writes at all.
-       */
-      bool progress = false;
-      bool is_buffer =
-         nir_intrinsic_image_dim(instr) == GLSL_SAMPLER_DIM_BUF;
-
-      bool is_any_written =
-         is_buffer ? state->buffers_written : state->images_written;
-
-      if (!(nir_intrinsic_access(instr) & ACCESS_NON_WRITEABLE) &&
-          !is_any_written) {
-         progress = true;
-         nir_intrinsic_set_access(instr,
-                                  nir_intrinsic_access(instr) |
-                                  ACCESS_NON_WRITEABLE);
-      }
-
-      if (can_reorder(state, nir_intrinsic_access(instr), is_buffer, false)) {
-         progress = true;
-         nir_intrinsic_set_access(instr,
-                                  nir_intrinsic_access(instr) |
-                                  ACCESS_CAN_REORDER);
-      }
+      return update_access(state, instr, true,
+                           nir_intrinsic_image_dim(instr) == GLSL_SAMPLER_DIM_BUF);
 
-      return progress;
-
-   case nir_intrinsic_load_deref:
-   case nir_intrinsic_image_deref_load: {
+   case nir_intrinsic_load_deref: {
       nir_variable *var = nir_intrinsic_get_var(instr, 0);
-
-      if (instr->intrinsic == nir_intrinsic_load_deref &&
-          var->data.mode != nir_var_mem_ssbo)
-         return false;
-
-      if (nir_intrinsic_access(instr) & ACCESS_CAN_REORDER)
+      if (var->data.mode != nir_var_mem_ssbo)
          return false;
 
-      bool progress = false;
-
-      /* Check if we were able to mark the whole variable non-writeable */
-      if (!(nir_intrinsic_access(instr) & ACCESS_NON_WRITEABLE) &&
-          var->data.access & ACCESS_NON_WRITEABLE) {
-         progress = true;
-         nir_intrinsic_set_access(instr,
-                                  nir_intrinsic_access(instr) |
-                                  ACCESS_NON_WRITEABLE);
-      }
+      return update_access(state, instr, false, true);
+   }
 
-      bool is_ssbo = var->data.mode == nir_var_mem_ssbo;
+   case nir_intrinsic_image_deref_load: {
+      nir_variable *var = nir_intrinsic_get_var(instr, 0);
 
-      bool is_buffer = is_ssbo ||
+      bool is_buffer =
          glsl_get_sampler_dim(glsl_without_array(var->type)) == GLSL_SAMPLER_DIM_BUF;
 
-      if (can_reorder(state, nir_intrinsic_access(instr), is_buffer, is_ssbo)) {
-         progress = true;
-         nir_intrinsic_set_access(instr,
-                                  nir_intrinsic_access(instr) |
-                                  ACCESS_CAN_REORDER);
-      }
-
-      return progress;
+      return update_access(state, instr, true, is_buffer);
    }
 
    default: