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

[Tom Eccles 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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tblah wrote:

Thanks for the answers everyone.

I meant "unknown memory effects" as in not specifying any at all. This would force passes to be as pessimistic as possible about this operation as they would have no way to reason about it.

However, I now think Slava is right that being maximally pessimistic could be overkill in the long run. Anyway, doing the same as the LLVM dialect is great for this PR.

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