[flang-commits] [flang] 041080f - [flang] Fix extent computation in finalization

[Peter Klausler via flang-commits]

Author: Peter Klausler
Date: 2022-03-09T09:01:02-08:00
New Revision: 041080fc9b7a245967f512923dae9d6af7cfbc57

URL: https://github.com/llvm/llvm-project/commit/041080fc9b7a245967f512923dae9d6af7cfbc57
DIFF: https://github.com/llvm/llvm-project/commit/041080fc9b7a245967f512923dae9d6af7cfbc57.diff

LOG: [flang] Fix extent computation in finalization

The code that computed the extent of a dimension of a
non-allocatable/non-automatic component array during
finalization had a reversed subtraction; fix, and
use variables to make the code a little more readable.

Differential Revision: https://reviews.llvm.org/D121163

Added: 
    

Modified: 
    flang/runtime/derived.cpp

Removed: 
    


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diff  --git a/flang/runtime/derived.cpp b/flang/runtime/derived.cpp
index f9e34b21c800f..bb47f6b7a3292 100644
--- a/flang/runtime/derived.cpp
+++ b/flang/runtime/derived.cpp
@@ -188,8 +188,10 @@ void Finalize(
       SubscriptValue extent[maxRank];
       const typeInfo::Value *bounds{comp.bounds()};
       for (int dim{0}; dim < comp.rank(); ++dim) {
-        extent[dim] = bounds[2 * dim].GetValue(&descriptor).value_or(0) -
-            bounds[2 * dim + 1].GetValue(&descriptor).value_or(0) + 1;
+        SubscriptValue lb{bounds[2 * dim].GetValue(&descriptor).value_or(0)};
+        SubscriptValue ub{
+            bounds[2 * dim + 1].GetValue(&descriptor).value_or(0)};
+        extent[dim] = ub >= lb ? ub - lb + 1 : 0;
       }
       StaticDescriptor<maxRank, true, 0> staticDescriptor;
       Descriptor &compDesc{staticDescriptor.descriptor()};