glsl-es-1.00: Only unroll a do-while-false loop once

This was the smallest test case that I could make that would reproduce
the bug, generate actual instructions (instead of constant folding to
nothing), and be small enough to run on any GPU supported by Mesa that
has GLES 2.0 (i.e., i915).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110953
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/tests/spec/glsl-es-1.00/execution/unroll-do-while-false-loop-only-once.shader_test b/tests/spec/glsl-es-1.00/execution/unroll-do-while-false-loop-only-once.shader_test
new file mode 100644
index 000000000..9f4edd660
--- /dev/null
+++ b/tests/spec/glsl-es-1.00/execution/unroll-do-while-false-loop-only-once.shader_test
@@ -0,0 +1,47 @@
+[require]
+GL ES >= 2.0
+GLSL ES >= 1.00
+
+[vertex shader passthrough]
+
+[fragment shader]
+precision mediump float;
+
+uniform float x[4];
+
+void main()
+{
+    float data[4];
+
+    for (int i = 0; i < 4; i++)
+	data[i] = x[i];
+
+    for (int i = 0; i < 3; i++) {
+	bool doSwap = data[i] > data[i + 1];
+
+	/* Per bugzilla 110953, a do-while-false loop that starts with
+	 * an if-statement can be unrolled twice instead of once.
+	 */
+	do {
+	    if (doSwap) {
+		float temp = data[i];
+		data[i] = data[i + 1];
+		data[i + 1] = temp;
+	    }
+	} while (false);
+    }
+
+    if (data[0] == 3. && data[1] == 2. && data[2] == 1. && data[3] == 4.)
+	gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);
+    else
+	gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
+}
+
+[test]
+uniform float x[0] 4.0
+uniform float x[1] 3.0
+uniform float x[2] 2.0
+uniform float x[3] 1.0
+
+draw rect -1 -1 2 2
+probe all rgba 0 1 0 1