From: Nicolai Hähnle <nicolai.haehnle@amd.com>
Date: Sat, 30 Apr 2016 06:36:59 +0000 (-0500)
Subject: compiler/glsl: do not downcast list sentinel
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=945c6887ab43a98a6e042841b2fb547aaef250e2;p=mesa.git

compiler/glsl: do not downcast list sentinel

This crashes gcc's undefined behaviour sanitizer.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
---

diff --git a/src/compiler/glsl/ir.cpp b/src/compiler/glsl/ir.cpp
index 750f61744e7..d69ab131199 100644
--- a/src/compiler/glsl/ir.cpp
+++ b/src/compiler/glsl/ir.cpp
@@ -869,7 +869,8 @@ ir_constant::ir_constant(const struct glsl_type *type, exec_list *value_list)
    /* Use each component from each entry in the value_list to initialize one
     * component of the constant being constructed.
     */
-   for (unsigned i = 0; i < type->components(); /* empty */) {
+   unsigned i = 0;
+   for (;;) {
       assert(value->as_constant() != NULL);
       assert(!value->is_tail_sentinel());
 
@@ -901,6 +902,8 @@ ir_constant::ir_constant(const struct glsl_type *type, exec_list *value_list)
 	    break;
       }
 
+      if (i >= type->components())
+	 break; /* avoid downcasting a list sentinel */
       value = (ir_constant *) value->next;
    }
 }