1 files changed, 47 insertions, 37 deletions

diff --git a/mlir/lib/Transforms/Utils/DialectConversion.cpp b/mlir/lib/Transforms/Utils/DialectConversion.cpp
index 36ee87b..df9700f 100644
--- a/mlir/lib/Transforms/Utils/DialectConversion.cpp
+++ b/mlir/lib/Transforms/Utils/DialectConversion.cpp
@@ -3406,10 +3406,19 @@ void TypeConverter::SignatureConversion::remapInput(
       SmallVector<Value, 1>(replacements.begin(), replacements.end())};
 }
 
-LogicalResult TypeConverter::convertType(Type t,
-                                         SmallVectorImpl<Type> &results) const {
-  assert(t && "expected non-null type");
-
+/// Internal implementation of the type conversion.
+/// This is used with either a Type or a Value as the first argument.
+/// - we can cache the context-free conversions until the last registered
+/// context-aware conversion.
+/// - we can't cache the result of type conversion happening after context-aware
+/// conversions, because the type converter may return different results for the
+/// same input type.
+LogicalResult
+TypeConverter::convertTypeImpl(PointerUnion<Type, Value> typeOrValue,
+                               SmallVectorImpl<Type> &results) const {
+  assert(typeOrValue && "expected non-null type");
+  Type t = (isa<Value>(typeOrValue)) ? cast<Value>(typeOrValue).getType()
+                                     : cast<Type>(typeOrValue);
   {
     std::shared_lock<decltype(cacheMutex)> cacheReadLock(cacheMutex,
                                                          std::defer_lock);
@@ -3431,52 +3440,53 @@ LogicalResult TypeConverter::convertType(Type t,
   // registered first.
   size_t currentCount = results.size();
 
+  // We can cache the context-free conversions until the last registered
+  // context-aware conversion. But only if we're processing a Value right now.
+  auto isCacheable = [&](int index) {
+    int numberOfConversionsUntilContextAware =
+        conversions.size() - 1 - contextAwareTypeConversionsIndex;
+    return index < numberOfConversionsUntilContextAware;
+  };
+
   std::unique_lock<decltype(cacheMutex)> cacheWriteLock(cacheMutex,
                                                         std::defer_lock);
 
-  for (const ConversionCallbackFn &converter : llvm::reverse(conversions)) {
-    if (std::optional<LogicalResult> result = converter(t, results)) {
-      if (t.getContext()->isMultithreadingEnabled())
-        cacheWriteLock.lock();
-      if (!succeeded(*result)) {
-        assert(results.size() == currentCount &&
-               "failed type conversion should not change results");
-        cachedDirectConversions.try_emplace(t, nullptr);
-        return failure();
-      }
-      auto newTypes = ArrayRef<Type>(results).drop_front(currentCount);
-      if (newTypes.size() == 1)
-        cachedDirectConversions.try_emplace(t, newTypes.front());
-      else
-        cachedMultiConversions.try_emplace(t, llvm::to_vector<2>(newTypes));
+  for (auto indexedConverter : llvm::enumerate(llvm::reverse(conversions))) {
+    const ConversionCallbackFn &converter = indexedConverter.value();
+    std::optional<LogicalResult> result = converter(typeOrValue, results);
+    if (!result) {
+      assert(results.size() == currentCount &&
+             "failed type conversion should not change results");
+      continue;
+    }
+    if (!isCacheable(indexedConverter.index()))
       return success();
-    } else {
+    if (t.getContext()->isMultithreadingEnabled())
+      cacheWriteLock.lock();
+    if (!succeeded(*result)) {
       assert(results.size() == currentCount &&
              "failed type conversion should not change results");
+      cachedDirectConversions.try_emplace(t, nullptr);
+      return failure();
     }
+    auto newTypes = ArrayRef<Type>(results).drop_front(currentCount);
+    if (newTypes.size() == 1)
+      cachedDirectConversions.try_emplace(t, newTypes.front());
+    else
+      cachedMultiConversions.try_emplace(t, llvm::to_vector<2>(newTypes));
+    return success();
   }
   return failure();
 }
 
-LogicalResult TypeConverter::convertType(Value v,
+LogicalResult TypeConverter::convertType(Type t,
                                          SmallVectorImpl<Type> &results) const {
-  assert(v && "expected non-null value");
-
-  // If this type converter does not have context-aware type conversions, call
-  // the type-based overload, which has caching.
-  if (!hasContextAwareTypeConversions)
-    return convertType(v.getType(), results);
+  return convertTypeImpl(t, results);
+}
 
-  // Walk the added converters in reverse order to apply the most recently
-  // registered first.
-  for (const ConversionCallbackFn &converter : llvm::reverse(conversions)) {
-    if (std::optional<LogicalResult> result = converter(v, results)) {
-      if (!succeeded(*result))
-        return failure();
-      return success();
-    }
-  }
-  return failure();
+LogicalResult TypeConverter::convertType(Value v,
+                                         SmallVectorImpl<Type> &results) const {
+  return convertTypeImpl(v, results);
 }
 
 Type TypeConverter::convertType(Type t) const {