Miscellaneous backward autodiff fixes. (#2665)

* Fix differentiable type registration

* Fix use of non-differentiable return value in a differentiable func.

* Fix use of primal inst that does not dominate the diff block.

* Fix primal inst hoisting, and add missing type legalization logic.

* Make `detach` defined on all differentiable T.

---------

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 29 insertions, 1 deletions

diff --git a/source/slang/slang-ir-util.cpp b/source/slang/slang-ir-util.cpp
index f3c4c2c82..3db036a8d 100644
--- a/source/slang/slang-ir-util.cpp
+++ b/source/slang/slang-ir-util.cpp
@@ -224,7 +224,7 @@ String dumpIRToString(IRInst* root)
     StringBuilder sb;
     StringWriter writer(&sb, Slang::WriterFlag::AutoFlush);
     IRDumpOptions options = {};
-#if 0
+#if 1
     options.flags = IRDumpOptions::Flag::DumpDebugIds;
 #endif
     dumpIR(root, options, nullptr, &writer);
@@ -487,6 +487,34 @@ IROp getSwapSideComparisonOp(IROp op)
     }
 }
 
+void setInsertBeforeOrdinaryInst(IRBuilder* builder, IRInst* inst)
+{
+    if (as<IRParam>(inst))
+    {
+        SLANG_RELEASE_ASSERT(as<IRBlock>(inst->getParent()));
+        auto lastParam = as<IRBlock>(inst->getParent())->getLastParam();
+        builder->setInsertAfter(lastParam);
+    }
+    else
+    {
+        builder->setInsertBefore(inst);
+    }
+}
+
+void setInsertAfterOrdinaryInst(IRBuilder* builder, IRInst* inst)
+{
+    if (as<IRParam>(inst))
+    {
+        SLANG_RELEASE_ASSERT(as<IRBlock>(inst->getParent()));
+        auto lastParam = as<IRBlock>(inst->getParent())->getLastParam();
+        builder->setInsertAfter(lastParam);
+    }
+    else
+    {
+        builder->setInsertAfter(inst);
+    }
+}
+
 bool isPureFunctionalCall(IRCall* call)
 {
     auto callee = getResolvedInstForDecorations(call->getCallee());