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

mjklemm · web-flow · commit 548901000dee · 2025-12-10T07:57:25.000+01:00
diff --git a/flang-rt/lib/runtime/assign.cpp b/flang-rt/lib/runtime/assign.cpp
@@ -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");
   }

Original file line number	Diff line number	Diff line change
`@@ -366,7 +366,7 @@ RT_API_ATTRS int AssignTicket::Begin(WorkQueue &workQueue) {`
`366`	`366`	`"assignment to unallocated allocatable",`
`367`	`367`	`to_.rank(), from_->rank());`
`368`	`368`	`}`
`369`		`- } else if (!to_.IsAllocated()) {`
	`369`	`+ } else if (!to_.IsAllocated() && to_.Elements()) {`
`370`	`370`	`workQueue.terminator().Crash(`
`371`	`371`	`"Assign: left-hand side variable is neither allocated nor allocatable");`
`372`	`372`	`}`