[Mesa-stable] [PATCH] st/glsl_to_tgsi: use correct writemask when converting generic intrinsics

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

This fixes a bug when lowering ballotARB: previously, using writemask 0xf,
emit_asm would create TGSI_OPCODE_BALLOT instructions that span two registers
to cover 4 64-bit channels. This could trample over other a neighbouring
temporary.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101360
Cc: 17.1 <mesa-stable at lists.freedesktop.org>
---
 src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index c5d2e0f..cb86392 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -3906,20 +3906,22 @@ glsl_to_tgsi_visitor::visit_image_intrinsic(ir_call *ir)
    if (imgvar->data.memory_volatile)
       inst->buffer_access |= TGSI_MEMORY_VOLATILE;
 }
 
 void
 glsl_to_tgsi_visitor::visit_generic_intrinsic(ir_call *ir, unsigned op)
 {
    ir->return_deref->accept(this);
    st_dst_reg dst = st_dst_reg(this->result);
 
+   dst.writemask = u_bit_consecutive(0, ir->return_deref->var->type->vector_elements);
+
    st_src_reg src[4] = { undef_src, undef_src, undef_src, undef_src };
    unsigned num_src = 0;
    foreach_in_list(ir_rvalue, param, &ir->actual_parameters) {
       assert(num_src < ARRAY_SIZE(src));
 
       this->result.file = PROGRAM_UNDEFINED;
       param->accept(this);
       assert(this->result.file != PROGRAM_UNDEFINED);
 
       src[num_src] = this->result;
-- 
2.9.3