[flang-commits] [flang] [flang][rfc] Add represention of volatile references (PR #132486)

[Slava Zakharin via flang-commits]

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@@ -37,6 +37,15 @@ namespace {
 #include "flang/Optimizer/Dialect/CanonicalizationPatterns.inc"
 } // namespace
 
+static void addVolatileMemoryEffects(
+    mlir::Type type, llvm::SmallVectorImpl<mlir::SideEffects::EffectInstance<
+                         mlir::MemoryEffects::Effect>> &effects) {
+  if (fir::isa_volatile_ref_type(type)) {
+    effects.emplace_back(mlir::MemoryEffects::Read::get());
+    effects.emplace_back(mlir::MemoryEffects::Write::get());
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vzakhari wrote:

It may be okay to follow the precedent in LLVM dialect, but I think there is a room for improvement.  Per LLVM LangRef, `volatile` does allow reordering non-volatile operations with regards to volatile operations, so I wonder if volatile operations should be reading/writing from/to a dedicated `volatile` (or `inaccessible`) resource.

No need to address it in this PR.

https://github.com/llvm/llvm-project/pull/132486