Don't emitting an imported declaration unless it is used.

This helps avoid the problem where we emit a function that does a `discard` and thus get a GLSL compilation failure in a vertex shader (that doesn't even call the function).

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/render/unused-discard.slang b/tests/render/unused-discard.slang
new file mode 100644
index 000000000..034735840
--- /dev/null
+++ b/tests/render/unused-discard.slang
@@ -0,0 +1,27 @@
+//TEST_IGNORE_FILE:
+
+// This file implements the "library" code
+// that both the HLSL and GLSL shaders share.
+//
+// This code is written in Slang (more or less
+// just HLSL), and will be translated as needed
+// for each of the targets.
+
+float3 transformColor(float3 color)
+{
+	float3 result;
+
+	result.x = sin(20.0 * (color.x + color.y));
+	result.y = saturate(cos(color.z * 30.0));
+	result.z = sin(color.x * color.y * color.z * 100.0);
+
+	result = 0.5 * (result + 1);
+
+	return result;
+}
+
+void doConditionalDiscard(float3 color)
+{
+	if(color.x < 0.5)
+		discard;
+}