[clang] [OpenMP] Don't emit redundant zero-sized mapping nodes for overlapped structs (PR #148947)

[Julian Brown via cfe-commits]

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@@ -7080,6 +7080,111 @@ class MappableExprsHandler {
     return ConstLength.getSExtValue() != 1;
   }
 
+  /// A helper class to copy structures with overlapped elements, i.e. those
+  /// which have mappings of both "s" and "s.mem".  Consecutive elements that
+  /// are not explicitly copied have mapping nodes synthesized for them,
+  /// taking care to avoid generating zero-sized copies.
+  class CopyOverlappedEntryGaps {
+    CodeGenFunction &CGF;
+    MapCombinedInfoTy &CombinedInfo;
+    OpenMPOffloadMappingFlags Flags;
+    const ValueDecl *MapDecl;
+    const Expr *MapExpr;
+    Address BP;
+    bool IsNonContiguous;
+    uint64_t DimSize;
+    // These elements track the position as the struct is iterated over
+    // (in order of increasing element address).
+    const RecordDecl *LastParent = nullptr;
+    uint64_t Cursor = 0;
+    unsigned LastIndex = -1u;
+    Address LB;
+
+  public:
+    CopyOverlappedEntryGaps(CodeGenFunction &_CGF,
+                            MapCombinedInfoTy &_CombinedInfo,
+                            OpenMPOffloadMappingFlags _Flags,
+                            const ValueDecl *_MapDecl, const Expr *_MapExpr,
+                            Address _BP, Address _LB, bool _IsNonContiguous,
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jtb20 wrote:

Fixed, thanks.

https://github.com/llvm/llvm-project/pull/148947