Mesa (7.9): glsl: fix crash in loop analysis when some controls can' t be determined

[Ian Romanick]

Module: Mesa
Branch: 7.9
Commit: 6333f1d2246e68688f0f6939ae7bafb8b52d642b
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=6333f1d2246e68688f0f6939ae7bafb8b52d642b

Author: Aras Pranckevicius <aras at unity3d.com>
Date:   Thu Sep 30 12:47:31 2010 +0300

glsl: fix crash in loop analysis when some controls can't be determined

Fixes loop-07.frag.
(cherry picked from commit d67df5dd9db1cede92f1b177c890f83809bb4582)

---

 src/glsl/loop_controls.cpp |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/src/glsl/loop_controls.cpp b/src/glsl/loop_controls.cpp
index 2ef3d30..b528810 100644
--- a/src/glsl/loop_controls.cpp
+++ b/src/glsl/loop_controls.cpp
@@ -85,6 +85,9 @@ int
 calculate_iterations(ir_rvalue *from, ir_rvalue *to, ir_rvalue *increment,
 		     enum ir_expression_operation op)
 {
+   if (from == NULL || to == NULL || increment == NULL)
+      return -1;
+
    void *mem_ctx = talloc_init("%s", __func__);
 
    ir_expression *const sub =