From 051ae8acec0a641bcaf86e7eeff35eff29e8922d Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Mon, 9 Dec 2024 04:47:53 -0800
Subject: Fix crash during emitCast of attributed type, allow MaxIters to take
 linktime const. (#5791)

* Fix crash during emitCast of attributed type.

* Allow [MaxIters] to take link time constants.

---------

Co-authored-by: Ellie Hermaszewska <ellieh@nvidia.com>
---
 source/slang/slang-ast-modifier.h     |  2 +-
 source/slang/slang-check-modifier.cpp |  6 +-----
 source/slang/slang-ir-insts.h         |  9 +++++++--
 source/slang/slang-ir.cpp             |  2 ++
 source/slang/slang-lower-to-ir.cpp    | 16 ++++++++++------
 5 files changed, 21 insertions(+), 14 deletions(-)

(limited to 'source')

diff --git a/source/slang/slang-ast-modifier.h b/source/slang/slang-ast-modifier.h
index ee9b55334..863ffaef2 100644
--- a/source/slang/slang-ast-modifier.h
+++ b/source/slang/slang-ast-modifier.h
@@ -744,7 +744,7 @@ class MaxItersAttribute : public Attribute
 {
     SLANG_AST_CLASS(MaxItersAttribute)
 
-    int32_t value = 0;
+    IntVal* value = 0;
 };
 
 // An inferred max iteration count on a loop.
diff --git a/source/slang/slang-check-modifier.cpp b/source/slang/slang-check-modifier.cpp
index 0794279a7..a1e0f7876 100644
--- a/source/slang/slang-check-modifier.cpp
+++ b/source/slang/slang-check-modifier.cpp
@@ -720,11 +720,7 @@ Modifier* SemanticsVisitor::validateAttribute(
         }
         else
         {
-            auto cint = checkConstantIntVal(attr->args[0]);
-            if (cint)
-            {
-                maxItersAttrs->value = (int32_t)cint->getValue();
-            }
+            maxItersAttrs->value = checkLinkTimeConstantIntVal(attr->args[0]);
         }
     }
     else if (const auto userDefAttr = as<UserDefinedAttribute>(attr))
diff --git a/source/slang/slang-ir-insts.h b/source/slang/slang-ir-insts.h
index 4c7272755..829e72575 100644
--- a/source/slang/slang-ir-insts.h
+++ b/source/slang/slang-ir-insts.h
@@ -4637,9 +4637,14 @@ public:
             getIntValue(getIntType(), IRIntegerValue(mode)));
     }
 
-    void addLoopMaxItersDecoration(IRInst* value, IntegerLiteralValue iters)
+    void addLoopMaxItersDecoration(IRInst* value, IRIntegerValue iters)
     {
-        addDecoration(value, kIROp_LoopMaxItersDecoration, getIntValue(getIntType(), iters));
+        addDecoration(value, kIROp_LoopMaxItersDecoration, getIntValue(iters));
+    }
+
+    void addLoopMaxItersDecoration(IRInst* value, IRInst* iters)
+    {
+        addDecoration(value, kIROp_LoopMaxItersDecoration, iters);
     }
 
     void addLoopForceUnrollDecoration(IRInst* value, IntegerLiteralValue iters)
diff --git a/source/slang/slang-ir.cpp b/source/slang/slang-ir.cpp
index f6c662a98..29fbcc3c9 100644
--- a/source/slang/slang-ir.cpp
+++ b/source/slang/slang-ir.cpp
@@ -3890,6 +3890,8 @@ enum class TypeCastStyle
 };
 static TypeCastStyle _getTypeStyleId(IRType* type)
 {
+    type = (IRType*)unwrapAttributedType(type);
+
     if (auto vectorType = as<IRVectorType>(type))
     {
         return _getTypeStyleId(vectorType->getElementType());
diff --git a/source/slang/slang-lower-to-ir.cpp b/source/slang/slang-lower-to-ir.cpp
index 75cf421af..ce6f8cb42 100644
--- a/source/slang/slang-lower-to-ir.cpp
+++ b/source/slang/slang-lower-to-ir.cpp
@@ -5938,7 +5938,8 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
 
         if (auto maxItersAttr = stmt->findModifier<MaxItersAttribute>())
         {
-            getBuilder()->addLoopMaxItersDecoration(inst, maxItersAttr->value);
+            auto iters = lowerVal(context, maxItersAttr->value);
+            getBuilder()->addLoopMaxItersDecoration(inst, getSimpleVal(context, iters));
         }
         else if (auto inferredMaxItersAttr = stmt->findModifier<InferredMaxItersAttribute>())
         {
@@ -6028,12 +6029,15 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
         {
             if (auto maxIters = stmt->findModifier<MaxItersAttribute>())
             {
-                if (inferredMaxIters->value < maxIters->value)
+                if (auto constIntVal = as<ConstantIntVal>(maxIters->value))
                 {
-                    context->getSink()->diagnose(
-                        maxIters,
-                        Diagnostics::forLoopTerminatesInFewerIterationsThanMaxIters,
-                        inferredMaxIters->value);
+                    if (inferredMaxIters->value < constIntVal->getValue())
+                    {
+                        context->getSink()->diagnose(
+                            maxIters,
+                            Diagnostics::forLoopTerminatesInFewerIterationsThanMaxIters,
+                            inferredMaxIters->value);
+                    }
                 }
             }
         }
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