glsl: fix optimization of discard nested multiple levels

The order of optimizations can lead to the conditional discard optimization
being applied twice to the same discard statement. In this case, we must
ensure that both conditions are applied.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96762
Cc: [email protected]
Tested-by: Kai Wasserbäch <[email protected]>
Reviewed-by: Tapani Pälli <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>
(cherry picked from commit 21556d86fc74d91ab58a7496a876ad33e0f950df)
[Emil Velikov: s/get_head_raw()/head/]
Signed-off-by: Emil Velikov <[email protected]>

Conflicts:
	src/compiler/glsl/opt_conditional_discard.cpp

1 files changed, 8 insertions, 1 deletions

diff --git a/src/compiler/glsl/opt_conditional_discard.cpp b/src/compiler/glsl/opt_conditional_discard.cpp
index 1ca8803f643..a27bead78f6 100644
--- a/src/compiler/glsl/opt_conditional_discard.cpp
+++ b/src/compiler/glsl/opt_conditional_discard.cpp
@@ -72,7 +72,14 @@ opt_conditional_discard_visitor::visit_leave(ir_if *ir)
 
    /* Move the condition and replace the ir_if with the ir_discard. */
    ir_discard *discard = (ir_discard *) ir->then_instructions.head;
-   discard->condition = ir->condition;
+   if (!discard->condition)
+      discard->condition = ir->condition;
+   else {
+      void *ctx = ralloc_parent(ir);
+      discard->condition = new(ctx) ir_expression(ir_binop_logic_and,
+                                                  ir->condition,
+                                                  discard->condition);
+   }
    ir->replace_with(discard);
 
    progress = true;