mesa: add/update comments in _mesa_copy_buffer_subdata()

[mesa.git] / src / mesa / drivers / dri / i965 / brw_vec4_copy_propagation.cpp

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
index 08d8f5b7034f302487a70f10c970c34ddc5fe1df..4d27c53ddf390f8cbdb48bc1991b1eb2f0044f5a 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
@@ -297,23 +297,24 @@ vec4_visitor::opt_copy_propagation()
       }
 
       /* Track available source registers. */
-      const int reg = virtual_grf_reg_map[inst->dst.reg] + inst->dst.reg_offset;
+      if (inst->dst.file == GRF) {
+        const int reg =
+           virtual_grf_reg_map[inst->dst.reg] + inst->dst.reg_offset;
 
-      /* Update our destination's current channel values.  For a direct copy,
-       * the value is the newly propagated source.  Otherwise, we don't know
-       * the new value, so clear it.
-       */
-      bool direct_copy = is_direct_copy(inst);
-      for (int i = 0; i < 4; i++) {
-        if (inst->dst.writemask & (1 << i)) {
-           cur_value[reg][i] = direct_copy ? &inst->src[0] : NULL;
+        /* Update our destination's current channel values.  For a direct copy,
+         * the value is the newly propagated source.  Otherwise, we don't know
+         * the new value, so clear it.
+         */
+        bool direct_copy = is_direct_copy(inst);
+        for (int i = 0; i < 4; i++) {
+           if (inst->dst.writemask & (1 << i)) {
+              cur_value[reg][i] = direct_copy ? &inst->src[0] : NULL;
+           }
         }
-      }
 
-      /* Clear the records for any registers whose current value came from
-       * our destination's updated channels, as the two are no longer equal.
-       */
-      if (inst->dst.file == GRF) {
+        /* Clear the records for any registers whose current value came from
+         * our destination's updated channels, as the two are no longer equal.
+         */
         if (inst->dst.reladdr)
            memset(cur_value, 0, sizeof(cur_value));
         else {