[flang-commits] [PATCH] D144134: [flang][runtime] MayAlias() must be false for Unallocated descriptors

[Peter Klausler via Phabricator via flang-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG74a5d7471fbd: [flang][runtime] MayAlias() must be false for unallocated descriptors (authored by klausler).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D144134/new/

https://reviews.llvm.org/D144134

Files:
  flang/runtime/assign.cpp


Index: flang/runtime/assign.cpp
===================================================================
--- flang/runtime/assign.cpp
+++ flang/runtime/assign.cpp
@@ -126,6 +126,11 @@
 // possibly overlap in memory?  Note that the descriptors themeselves
 // are included in the test.
 static bool MayAlias(const Descriptor &x, const Descriptor &y) {
+  const char *xBase{x.OffsetElement()};
+  const char *yBase{y.OffsetElement()};
+  if (!xBase || !yBase) {
+    return false; // not both allocated
+  }
   const char *xDesc{reinterpret_cast<const char *>(&x)};
   const char *xDescLast{xDesc + x.SizeInBytes()};
   const char *yDesc{reinterpret_cast<const char *>(&y)};
@@ -133,8 +138,6 @@
   std::int64_t xLeast, xMost, yLeast, yMost;
   MaximalByteOffsetRange(x, xLeast, xMost);
   MaximalByteOffsetRange(y, yLeast, yMost);
-  const char *xBase{x.OffsetElement()};
-  const char *yBase{y.OffsetElement()};
   if (RangesOverlap(xDesc, xDescLast, yBase + yLeast, yBase + yMost) ||
       RangesOverlap(yDesc, yDescLast, xBase + xLeast, xBase + xMost)) {
     // A descriptor overlaps with the storage described by the other;


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