[flang-commits] [flang] [flang][openmp] Fix incorrect reduction for array section in OpenMP DO SIMD (PR #192394)

[Sergio Afonso via flang-commits]

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@@ -696,6 +699,21 @@ bool ReductionProcessor::processReductionArguments(
   }
 
   for (const semantics::Symbol *symbol : reductionSymbols) {
+    // If a cached reduction variable exists for this symbol, reuse it.
+    // This ensures that composite constructs (e.g. DO SIMD) where both
+    // the outer wrapper (wsloop) and inner wrapper (simd) process the same
+    // reduction clause share the same SSA value, enabling genLoopVars()'s
+    // IRMapping to correctly remap inner wrapper operands to outer wrapper
+    // block arguments.
+    if (reductionVarCache) {
+      auto it = reductionVarCache->find(symbol);
+      if (it != reductionVarCache->end()) {
+        reductionVars.push_back(it->second);
+        reduceVarByRef.push_back(doReductionByRef(it->second));
+        continue;
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skatrak wrote:

My bad, somehow I misread this as having another loop the `continue` statement impacted. We indeed avoid multiple insertions, so things stay in sync. Thanks for the detailed explanation.

https://github.com/llvm/llvm-project/pull/192394