[Piglit] [PATCH] glsl-1.10: test for crash in loop analysis

[Timothy Arceri]

This test for a crash in Mesa seen in an Assasins Creed Odyssey shader.
---
 ...riable-iteration-limit-unroll4.shader_test | 88 +++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 tests/spec/glsl-1.10/execution/vs-loop-variable-iteration-limit-unroll4.shader_test

diff --git a/tests/spec/glsl-1.10/execution/vs-loop-variable-iteration-limit-unroll4.shader_test b/tests/spec/glsl-1.10/execution/vs-loop-variable-iteration-limit-unroll4.shader_test
new file mode 100644
index 000000000..38fdda4ca
--- /dev/null
+++ b/tests/spec/glsl-1.10/execution/vs-loop-variable-iteration-limit-unroll4.shader_test
@@ -0,0 +1,88 @@
+# This tests unrolling of a loop with a single exit point but where the
+# exact trip count is unknown, only the max iteration count (4) is known.
+#
+# Here we test all possible outcomes for the loop and also add some
+# unreachable code to make sure it is not accessible after unrolling.
+[require]
+GLSL >= 1.10
+
+[vertex shader]
+uniform int loop_count;
+uniform int loop_count2;
+
+void main()
+{
+  gl_Position = gl_Vertex;
+
+  vec4 colour = vec4(1.0, 1.0, 1.0, 1.0);
+
+  int i = 0;
+  int j = 0;
+  int x = 0;
+
+  /* Here we add a second && and put the known limit i < 4 in parentheses in
+   * order to trigger a Mesa bug seen in a Assasins Creed Odyssey shader
+   */
+  while (x < loop_count && (i < 4 && j < loop_count2)) {
+    if (x == 0 && i == 0)
+      colour = vec4(0.0, 0.25, 0.0, 1.0);
+
+    if (x == 2 && i == 1 && j == 4)
+      colour = vec4(0.0, 0.5, 0.0, 1.0);
+
+    if (x == 4 && i == 2 && j == 8)
+      colour = vec4(0.0, 0.75, 0.0, 1.0);
+
+    if (x == 6 && i == 3 && j == 12)
+      colour = vec4(0.0, 1.0, 0.0, 1.0);
+
+    /* This should be unreachable */
+    if (x >= 8 || i >= 4)
+      colour = vec4(1.0, 0.0, 0.0, 1.0);
+
+    i++;
+    x+=2;
+    j+=4;
+  }
+
+  gl_FrontColor = colour;
+}
+
+[fragment shader]
+void main()
+{
+  gl_FragColor = gl_Color;
+}
+
+[test]
+clear color 0.5 0.5 0.5 0.5
+
+uniform int loop_count 0
+uniform int loop_count2 16
+draw rect -1 -1 2 2
+probe all rgba 1.0 1.0 1.0 1.0
+
+uniform int loop_count 2
+uniform int loop_count2 16
+draw rect -1 -1 2 2
+probe all rgba 0.0 0.25 0.0 1.0
+
+uniform int loop_count 4
+uniform int loop_count2 16
+draw rect -1 -1 2 2
+probe all rgba 0.0 0.5 0.0 1.0
+
+uniform int loop_count 6
+uniform int loop_count2 16
+draw rect -1 -1 2 2
+probe all rgba 0.0 0.75 0.0 1.0
+
+uniform int loop_count 8
+uniform int loop_count2 16
+draw rect -1 -1 2 2
+probe all rgba 0.0 1.0 0.0 1.0
+
+uniform int loop_count 10
+uniform int loop_count2 16
+draw rect -1 -1 2 2
+probe all rgba 0.0 1.0 0.0 1.0
-- 
2.20.1