[flang-commits] [flang] [flang] Fix segfault in CSHIFT/EOSHIFT with dynamically optional DIM (PR #184431)

[Slava Zakharin via flang-commits]

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@@ -509,9 +534,33 @@ mlir::Value HlfirEOShiftLowering::lowerImpl(
   mlir::Value shift = operands[1];
   mlir::Value boundary = operands[2];
   mlir::Value dim = operands[3];
-  // If DIM is present, then dereference it if it is a ref.
-  if (dim)
+  if (loweredActuals[3] && loweredActuals[3]->handleDynamicOptional()) {
+    // DIM is a dynamically optional dummy argument.
+    // Use getIsPresent() directly (per eugeneepshteyn's review) rather than a
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vzakhari wrote:

Please also remove the user ids and the special symbol in this comment.

https://github.com/llvm/llvm-project/pull/184431