diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index 98ecd251ddf..5815e31732e 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -1472,7 +1472,7 @@ vec4_visitor::emit_block_move(dst_reg *dst, src_reg *src,
    dst->writemask = (1 << type->vector_elements) - 1;
 
    /* Do we need to worry about swizzling a swizzle? */
-   assert(src->swizzle = BRW_SWIZZLE_NOOP);
+   assert(src->swizzle == BRW_SWIZZLE_NOOP);
    src->swizzle = swizzle_for_size(type->vector_elements);
 
    vec4_instruction *inst = emit(MOV(*dst, *src));