diff --git a/src/intel/compiler/brw_fs_register_coalesce.cpp b/src/intel/compiler/brw_fs_register_coalesce.cpp
index 51e9af4a72f..24aa25c94e6 100644
--- a/src/intel/compiler/brw_fs_register_coalesce.cpp
+++ b/src/intel/compiler/brw_fs_register_coalesce.cpp
@@ -177,7 +177,8 @@ can_coalesce_vars(const fs_live_variables &live, const cfg_t *cfg,
          /* See the big comment above */
          if (regions_overlap(scan_inst->dst, scan_inst->size_written,
                              inst->src[0], inst->size_read(0))) {
-            if (seen_copy || scan_block != block)
+            if (seen_copy || scan_block != block ||
+                (scan_inst->force_writemask_all && !inst->force_writemask_all))
                return false;
             seen_src_write = true;
          }