From a5342abd5b2a57cc429233216ddf096321503372 Mon Sep 17 00:00:00 2001
From: Pascal Lecocq <plecocq@imageworks.com>
Date: Thu, 18 May 2023 19:31:25 -0700
Subject: [PATCH] Fix userdata derivatives for interpolated params on GPU

Signed-off-by: Pascal Lecocq <pascal.lecocq@gmail.com>
---
 src/liboslexec/llvm_instance.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/liboslexec/llvm_instance.cpp b/src/liboslexec/llvm_instance.cpp
index 468338a8f..1b31494ae 100644
--- a/src/liboslexec/llvm_instance.cpp
+++ b/src/liboslexec/llvm_instance.cpp
@@ -563,6 +563,8 @@ BackendLLVM::llvm_assign_initial_value(const Symbol& sym, bool force)
             llvm::Value* dst = llvm_void_ptr(sym);
             TypeDesc t       = sym.typespec().simpletype();
             ll.op_memcpy(dst, src, t.size(), t.basesize());
+            if (sym.has_derivs())
+                llvm_zero_derivs(sym);
 #endif
         } else if (!sym.lockgeom() && !sym.typespec().is_closure()) {
             // geometrically-varying param; memcpy its default value