i965: Fix a crash in the texture gradient lowering pass with cube samplers

We need to swizzle the rhs to match the number of components in the writemask,
otherwise we'll hit an assertion in ir_assignment.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

diff --git a/src/mesa/drivers/dri/i965/brw_lower_texture_gradients.cpp b/src/mesa/drivers/dri/i965/brw_lower_texture_gradients.cpp
index 9679d2842075a55852510d99e628e1f054a54794..0424003ffd504948cb6bbacb30d9ab961130ce36 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_lower_texture_gradients.cpp
+++ b/src/mesa/drivers/dri/i965/brw_lower_texture_gradients.cpp
@@ -124,7 +124,9 @@ lower_texture_grad_visitor::visit_leave(ir_texture *ir)
       new(mem_ctx) ir_variable(grad_type, "size", ir_var_temporary);
    if (ir->sampler->type->sampler_dimensionality == GLSL_SAMPLER_DIM_CUBE) {
       base_ir->insert_before(size);
-      base_ir->insert_before(assign(size, expr(ir_unop_i2f, txs), WRITEMASK_XY));
+      base_ir->insert_before(assign(size,
+                                    swizzle_for_size(expr(ir_unop_i2f, txs), 2),
+                                    WRITEMASK_XY));
       base_ir->insert_before(assign(size, new(mem_ctx) ir_constant(1.0f), WRITEMASK_Z));
    } else {
       emit(size, expr(ir_unop_i2f,