Type legalization and autodiff bug fixes. (#2722)

* Bug fixes.

* Fix.

* Only perform autodiff for functions whose derivative is actually used.

* Fix loop optimize bug.

* Fix high order diff.

* Fix trivial diff func generation.

* Fixes.

* Cleanup.

---------

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

1 files changed, 10 insertions, 5 deletions

diff --git a/source/slang/slang-ir-simplify-cfg.cpp b/source/slang/slang-ir-simplify-cfg.cpp
index b814442fa..e98d14a0c 100644
--- a/source/slang/slang-ir-simplify-cfg.cpp
+++ b/source/slang/slang-ir-simplify-cfg.cpp
@@ -105,7 +105,7 @@ static bool doesLoopHasSideEffect(IRGlobalValueWithCode* func, IRLoop* loopInst)
         loopBlocks.Add(b);
     auto addressHasOutOfLoopUses = [&](IRInst* addr)
     {
-        // The entire access chain of `addr` must have no uses out side the loop.
+        // The entire access chain of `addr` must have no uses outside the loop.
         // The root variable must be a local var.
         for (auto chainNode = addr; chainNode;)
         {
@@ -123,6 +123,11 @@ static bool doesLoopHasSideEffect(IRGlobalValueWithCode* func, IRLoop* loopInst)
                 chainNode = chainNode->getOperand(0);
                 continue;
             case kIROp_Var:
+                if (auto rate = chainNode->getFullType()->getRate())
+                {
+                    if (!as<IRConstExprRate>(rate))
+                        return true;
+                }
                 break;
             default:
                 return true;
@@ -143,10 +148,6 @@ static bool doesLoopHasSideEffect(IRGlobalValueWithCode* func, IRLoop* loopInst)
                     return true;
             }
 
-            // The inst can't possibly have side effect? Skip it.
-            if (!inst->mightHaveSideEffects())
-                continue;
-
             // This inst might have side effect, try to prove that the
             // side effect does not leak beyond the scope of the loop.
             if (auto call = as<IRCall>(inst))
@@ -187,6 +188,10 @@ static bool doesLoopHasSideEffect(IRGlobalValueWithCode* func, IRLoop* loopInst)
             }
             else
             {
+                // The inst can't possibly have side effect? Skip it.
+                if (!inst->mightHaveSideEffects())
+                    continue;
+
                 // For all other insts, we assume it has a global side effect.
                 return true;
             }