glsl/loops: replace loop controls with a normative bound.

This patch replaces the ir_loop fields "from", "to", "increment",
"counter", and "cmp" with a single integer ("normative_bound") that
serves the same purpose.

I've used the name "normative_bound" to emphasize the fact that the
back-end is required to emit code to prevent the loop from running
more than normative_bound times.  (By contrast, an "informative" bound
would be a bound that is informational only).

Reviewed-by: Jordan Justen <[email protected]>
Reviewed-by: Ian Romanick <[email protected]>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp
index 9fd10d1d91c..583cdef9f26 100644
--- a/src/mesa/program/ir_to_mesa.cpp
+++ b/src/mesa/program/ir_to_mesa.cpp
@@ -759,8 +759,10 @@ ir_to_mesa_visitor::visit(ir_variable *ir)
 void
 ir_to_mesa_visitor::visit(ir_loop *ir)
 {
-   /* Any bounded loops should have been lowered by lower_bounded_loops(). */
-   assert(ir->counter == NULL);
+   /* Any normative loop bounds should have been lowered by
+    * lower_bounded_loops().
+    */
+   assert(ir->normative_bound < 0);
 
    emit(NULL, OPCODE_BGNLOOP);