[flang-commits] [flang] [flang] Do not hoist all scalar sub-expressions from WHERE constructs (PR #91395)

[Valentin Clement バレンタイン クレメン via flang-commits]

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@@ -907,13 +918,36 @@ void MaskedArrayExpr::generateNoneElementalPart(fir::FirOpBuilder &builder,
                                                 mlir::IRMapping &mapper) {
   assert(!noneElementalPartWasGenerated &&
          "none elemental parts already generated");
-  // Clone all operations, except the elemental and the final yield.
-  mlir::Block::OpListType &ops = region.back().getOperations();
-  assert(!ops.empty() && "yield block cannot be empty");
-  auto end = ops.end();
-  for (auto opIt = ops.begin(); std::next(opIt) != end; ++opIt)
-    if (!elementalParts.contains(&*opIt))
-      (void)builder.clone(*opIt, mapper);
+  if (isOuterMaskExpr) {
+    // The outer mask expression is actually not masked, it is dealt as
+    // such so that its elemental part, if any, can be inlined in the WHERE
+    // loops. But all of the operations outside of hlfir.elemental/
+    // hlfir.elemental_addr must be emitted now because their value may be
+    // required to deduce the mask shape and the WHERE loop bounds.
+    for (mlir::Operation &op : region.back().without_terminator())
+      if (!elementalParts.contains(&op))
+        (void)builder.clone(op, mapper);
+  } else {
+    // For actual masked expressions, Fortran requires elemental expressions,
+    // even the scalar ones that are no encoded with hlfir.elemental, to be
----------------
clementval wrote:

```suggestion
    // even the scalar ones that are not encoded with hlfir.elemental, to be
```
?

https://github.com/llvm/llvm-project/pull/91395