[flang-commits] [flang] [flang][nfc] Support volatility in Fir ops (PR #134858)

[via flang-commits]

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@@ -15,13 +15,26 @@
 
 namespace fir {
 
-/// Return true iff the Operation is a non-volatile LoadOp or ArrayLoadOp.
-inline bool nonVolatileLoad(mlir::Operation *op) {
-  if (auto load = mlir::dyn_cast<fir::LoadOp>(op))
-    return !load->getAttr("volatile");
-  if (auto arrLoad = mlir::dyn_cast<fir::ArrayLoadOp>(op))
-    return !arrLoad->getAttr("volatile");
-  return false;
+/// The LLVM dialect represents volatile memory accesses as read and write
+/// effects to an unknown memory location, but this may be overly conservative.
+/// LLVM Language Reference only specifies that volatile memory accesses
+/// must not be reordered relative to other volatile memory accesses, so it
+/// is more precise to use a separate memory resource for volatile memory
+/// accesses.
+inline void addVolatileMemoryEffects(
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jeanPerier wrote:

No specific concerns, I just wanted to make sure this was not forgotten and that the `getEffects` of HLFIR opertations would also be updated when relevant.
We do not have a lot of code motion at high level currently, but it will also be important to make sure high level operations referencing volatile memory are not moved without care.

https://github.com/llvm/llvm-project/pull/134858