[llvm] [Flang-rt] Implement same behavior as -O3 for zero-length arrays (PR #171480)

[Michael Klemm via llvm-commits]

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@@ -366,7 +366,7 @@ RT_API_ATTRS int AssignTicket::Begin(WorkQueue &workQueue) {
                                    "assignment to unallocated allocatable",
           to_.rank(), from_->rank());
     }
-  } else if (!to_.IsAllocated()) {
+  } else if (!to_.IsAllocated() && to_.Elements()) {
     workQueue.terminator().Crash(
         "Assign: left-hand side variable is neither allocated nor allocatable");
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mjklemm wrote:

I totally agree.  But Copilot tried hard to improve it :-)

https://github.com/llvm/llvm-project/pull/171480