arb_gpu_shader_int64: test masking after addition

There is an optimization in Mesa that tries to reassociate these
operations to improve the chances of CSE. However, the base mask used
is 0xffffffff.  This is not correct (but should still work) for 16-bit
and 8-bit values, but it means the high 32-bits of 64-bit values won't
get chopped off.

Part-of: <https://gitlab.freedesktop.org/mesa/piglit/-/merge_requests/469>

1 files changed, 36 insertions, 0 deletions

diff --git a/tests/spec/arb_gpu_shader_int64/fs-iand-of-iadd-int64.shader_test b/tests/spec/arb_gpu_shader_int64/fs-iand-of-iadd-int64.shader_test
new file mode 100644
index 000000000..ac24421fe
--- /dev/null
+++ b/tests/spec/arb_gpu_shader_int64/fs-iand-of-iadd-int64.shader_test
@@ -0,0 +1,36 @@
+[require]
+GLSL >= 4.00
+GL_ARB_gpu_shader_int64
+
+[vertex shader passthrough]
+
+[fragment shader]
+#extension GL_ARB_gpu_shader_int64: require
+
+out vec4 piglit_fragcolor;
+
+void main()
+{
+    /* The scale factor and the bias values ensure that every fragment will
+     * generate a value larger than (1 << 32).
+     */
+    uint64_t a = uint64_t(int(gl_FragCoord.x) + 8179) *
+		 uint64_t(int(gl_FragCoord.y) + 9931) * 1693ul;
+
+    /* Reassociating the addition and the masking will not have the
+     * same result.
+     */
+    uint64_t b = (a + 0x0ffffffffffffff0ul) & 0x00000000fffffff0ul;
+
+    if (b >= (1ul << 32))
+	piglit_fragcolor = vec4(1.0, 0.0, 0.0, 1.0);
+    else
+	piglit_fragcolor = vec4(0.0, 1.0, 0.0, 1.0);
+}
+
+[test]
+clear color 0.3 0.3 0.3 0.0
+clear
+
+draw rect -1 -1 2 2
+probe all rgba 0.0 1.0 0.0 1.0