Fix type checking & loop value hoisting (#2907)

* Fix type checking crash in language server.

* Fix loop var hoisting logic.

Fixes #2903.

* fix.

---------

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

5 files changed, 39 insertions, 17 deletions

diff --git a/source/slang/slang-check-constraint.cpp b/source/slang/slang-check-constraint.cpp
index cdffcf004..42d01a996 100644
--- a/source/slang/slang-check-constraint.cpp
+++ b/source/slang/slang-check-constraint.cpp
@@ -792,6 +792,8 @@ namespace Slang
         Type*  fst,
         Type*  snd)
     {
+        if (!fst) return false;
+
         if (fst->equals(snd)) return true;
 
         // An error type can unify with anything, just so we avoid cascading errors.
diff --git a/source/slang/slang-check-overload.cpp b/source/slang/slang-check-overload.cpp
index 4bd8506ed..0d10b05be 100644
--- a/source/slang/slang-check-overload.cpp
+++ b/source/slang/slang-check-overload.cpp
@@ -409,11 +409,12 @@ namespace Slang
             auto& arg = context.getArg(ii);
             auto argType = context.getArgType(ii);
             auto paramType = paramTypes[ii];
-
+            if (!paramType)
+                return false;
+            if (!argType)
+                return false;
             if (context.mode == OverloadResolveContext::Mode::JustTrying)
             {
-                SLANG_ASSERT(argType);
-
                 ConversionCost cost = kConversionCost_None;
                 if( context.disallowNestedConversions )
                 {
@@ -1656,7 +1657,11 @@ namespace Slang
         for( UInt aa = 0; aa < argCount; ++aa )
         {
             if(aa != 0) argsListBuilder << ", ";
-            context.getArgType(aa)->toText(argsListBuilder);
+            auto argType = context.getArgType(aa);
+            if (argType)
+                context.getArgType(aa)->toText(argsListBuilder);
+            else
+                argsListBuilder << "error";
         }
         argsListBuilder << ")";
         return argsListBuilder.produceString();
diff --git a/source/slang/slang-ir-autodiff-cfg-norm.cpp b/source/slang/slang-ir-autodiff-cfg-norm.cpp
index 1727f7d8f..30c8a934e 100644
--- a/source/slang/slang-ir-autodiff-cfg-norm.cpp
+++ b/source/slang/slang-ir-autodiff-cfg-norm.cpp
@@ -709,24 +709,30 @@ void normalizeCFG(
             IRBuilder builder(func);
             for (auto b : workList)
             {
-                for (auto inst : b->getChildren())
+                for (auto inst : b->getModifiableChildren())
                 {
                     // If inst has uses outside the loop body, we need to hoist it.
                     IRVar* tempVar = nullptr;
-                    for (auto use = inst->firstUse; use; use = use->nextUse)
+                    if (auto var = as<IRVar>(inst))
                     {
-                        auto userBlock = as<IRBlock>(use->getUser()->getParent());
-                        if (userBlock && !workListSet.contains(userBlock))
+                        for (auto use = inst->firstUse; use; use = use->nextUse)
                         {
-                            // Hoist the inst.
-                            if (auto var = as<IRVar>(inst))
+                            // If inst is an var, this is easy, we just move it to the
+                            // loop header.
+                            auto userBlock = as<IRBlock>(use->getUser()->getParent());
+                            if (userBlock && !workListSet.contains(userBlock))
                             {
-                                // If inst is an var, this is easy, we just move it to the
-                                // loop header.
                                 var->insertBefore(insertionPoint);
                                 break;
                             }
-                            else
+                        }
+                    }
+                    else
+                    {
+                        traverseUses(inst, [&](IRUse* use)
+                        {
+                            auto userBlock = as<IRBlock>(use->getUser()->getParent());
+                            if (userBlock && !workListSet.contains(userBlock))
                             {
                                 // For all other insts, we need to create a local var for it.
                                 if (!tempVar)
@@ -741,8 +747,7 @@ void normalizeCFG(
                                 auto load = builder.emitLoad(tempVar);
                                 builder.replaceOperand(use, load);
                             }
-                            break;
-                        }
+                        });
                     }
                 }
             }
@@ -751,6 +756,9 @@ void normalizeCFG(
     disableIRValidationAtInsert();
     constructSSA(module, func);
     enableIRValidationAtInsert();
+#if _DEBUG
+    validateIRInst(func);
+#endif
 }
 
 } // namespace Slang
diff --git a/source/slang/slang-ir-validate.cpp b/source/slang/slang-ir-validate.cpp
index 18229c9b6..bf1ce1956 100644
--- a/source/slang/slang-ir-validate.cpp
+++ b/source/slang/slang-ir-validate.cpp
@@ -144,7 +144,14 @@ namespace Slang
 
         auto operandParent = operandValue->getParent();
 
-        if (auto instParentBlock = as<IRBlock>(instParent))
+        auto instParentBlock = as<IRBlock>(instParent);
+        if (!instParentBlock && as<IRDecoration>(inst))
+        {
+            instParent = instParent->getParent();
+            instParentBlock = as<IRBlock>(instParent);
+        }
+
+        if (instParentBlock)
         {
             if (auto operandParentBlock = as<IRBlock>(operandParent))
             {
diff --git a/source/slang/slang-stdlib.cpp b/source/slang/slang-stdlib.cpp
index f80254ba6..1f8d0a97a 100644
--- a/source/slang/slang-stdlib.cpp
+++ b/source/slang/slang-stdlib.cpp
@@ -221,7 +221,7 @@ namespace Slang
     static const IntrinsicOpInfo intrinsicUnaryOps[] = {
         { kIROp_Neg,    "neg",              "-",    "__BuiltinArithmeticType",  ARITHMETIC_MASK },
         { kIROp_Not,    "logicalNot",       "!",    nullptr,                    BOOL_MASK | BOOL_RESULT },
-        { kIROp_BitNot, "not",              "~",    "__BuiltinIntegerType",     INT_MASK        },
+        { kIROp_BitNot, "not",              "~",    "__BuiltinLogicalType",     INT_MASK        },
     };
 
     static const IntrinsicOpInfo intrinsicBinaryOps[] = {