From: Nicolai Hähnle <nicolai.haehnle@amd.com>
Date: Tue, 26 Jul 2016 08:04:57 +0000 (+0200)
Subject: glsl: fix optimization of discard nested multiple levels
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=21556d86fc74d91ab58a7496a876ad33e0f950df;p=mesa.git

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: mesa-stable@lists.freedesktop.org
Tested-by: Kai Wasserbäch <kai@dev.carbon-project.org>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
---

diff --git a/src/compiler/glsl/opt_conditional_discard.cpp b/src/compiler/glsl/opt_conditional_discard.cpp
index 03665c37364..6d8a23460d9 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.get_head_raw();
-   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;