[clang] [llvm] [Clang][OpenMP] Non-contiguous strided update (PR #144635)

[Amit Tiwari via cfe-commits]

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@@ -7384,7 +7384,40 @@ class MappableExprsHandler {
     // dimension.
     uint64_t DimSize = 1;
 
-    bool IsNonContiguous = CombinedInfo.NonContigInfo.IsNonContiguous;
+    // Detects non-contiguous updates due to strided accesses.
+    // Sets the 'IsNonContiguous' flag so that the 'MapType' bits are set
+    // correctly when generating information to be passed to the runtime. The
+    // flag is set to true if any array section has a stride not equal to 1, or
+    // if the stride is not a constant expression (conservatively assumed
+    // non-contiguous).
+    bool IsNonContiguous = false;
+    for (const auto &Component : Components) {
+      const auto *OASE =
+          dyn_cast<ArraySectionExpr>(Component.getAssociatedExpression());
+      if (OASE) {
+        const Expr *StrideExpr = OASE->getStride();
+        if (StrideExpr) {
+          // Check if the stride is a constant integer expression
+          if (StrideExpr->isIntegerConstantExpr(CGF.getContext())) {
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amitamd7 wrote:

Yes, because `stride` can be a variable/complex expression that is determined only at runtime, so conservatively treating it as non-contiguous. 

https://github.com/llvm/llvm-project/pull/144635