glsl: move open-coded-bitfieldReverse tests to where they belong

Part-of: <https://gitlab.freedesktop.org/mesa/piglit/-/merge_requests/323>

1 files changed, 52 insertions, 0 deletions

diff --git a/tests/spec/ext_gpu_shader4/execution/open-coded-bitfieldReverse.shader_test b/tests/spec/ext_gpu_shader4/execution/open-coded-bitfieldReverse.shader_test
new file mode 100644
index 000000000..902746d07
--- /dev/null
+++ b/tests/spec/ext_gpu_shader4/execution/open-coded-bitfieldReverse.shader_test
@@ -0,0 +1,52 @@
+[require]
+GLSL >= 1.20
+GL_EXT_gpu_shader4
+
+[vertex shader passthrough]
+
+[fragment shader]
+#version 120
+#extension GL_EXT_gpu_shader4: require
+
+/* Adapted from the nir_opt_algebraic pattern that causes the bug:
+ *
+ *  step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16))
+ *  step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8))
+ *  step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4))
+ *  step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2))
+ *  step5 = ('ior(many-comm-expr)', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1))
+ *
+ *  return step5
+ *
+ * The problem was that this optimization triggered even on GPUs (e.g., Intel
+ * Sandybridge) that lack a BFREV instruction.
+ */
+unsigned int reverse(unsigned int u)
+{
+    unsigned int step1 = (u << 16) | (u >> 16);
+    unsigned int step2 = ((step1 & 0x00ff00ffu) << 8) | ((step1 & 0xff00ff00u) >> 8);
+    unsigned int step3 = ((step2 & 0x0f0f0f0fu) << 4) | ((step2 & 0xf0f0f0f0u) >> 4);
+    unsigned int step4 = ((step3 & 0x33333333u) << 2) | ((step3 & 0xccccccccu) >> 2);
+    unsigned int step5 = ((step4 & 0x55555555u) << 1) | ((step4 & 0xaaaaaaaau) >> 1);
+
+    return step5;
+}
+
+out vec4 piglit_fragcolor;
+
+uniform unsigned int value;
+uniform unsigned int expected;
+
+void main()
+{
+    piglit_fragcolor = (reverse(value) != expected)
+        ? vec4(1.0, 0.0, 0.0, 1.0)
+        : vec4(0.0, 1.0, 0.0, 1.0);
+}
+
+[test]
+uniform uint value    0x12345678
+uniform uint expected 0x1e6a2c48
+
+draw rect -1 -1 2 2
+probe all rgba 0.0 1.0 0.0 1.0