Destroy unused witness table after hoisting (#7009)

* Destroy unused witness table after hoisting

1 files changed, 3 insertions, 0 deletions

diff --git a/source/slang/slang-ir-autodiff.cpp b/source/slang/slang-ir-autodiff.cpp
index f70e30b72..6ad8c5dbb 100644
--- a/source/slang/slang-ir-autodiff.cpp
+++ b/source/slang/slang-ir-autodiff.cpp
@@ -3249,6 +3249,9 @@ struct AutoDiffPass : public InstPassBase
                     }
                 }
 
+                // Destroy the old witness table
+                innerResult.diffWitness->replaceUsesWith(newWitnessTable);
+                innerResult.diffWitness->removeAndDeallocate();
                 result.diffWitness =
                     hoistValueFromGeneric(builder, newWitnessTable, specInst, true);
             }