[flang] [llvm] [flang][llvm][OpenMP][OpenACC] Add implicit casts to omp.atomic and acc.atomic (PR #131603)

[Tom Eccles via llvm-commits]

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@@ -481,6 +538,30 @@ void genOmpAccAtomicCapture(Fortran::lower::AbstractConverter &converter,
   mlir::Type stmt2VarType =
       fir::getBase(converter.genExprValue(assign2.lhs, stmtCtx)).getType();
 
+  // Checks helpful in constructing the `atomic.capture` region
+  bool hasSingleVariable =
+      Fortran::semantics::checkForSingleVariableOnRHS(stmt1);
+  bool hasSymMatch = Fortran::semantics::checkForSymbolMatch(stmt2);
+
+  // Implicit casts
+  mlir::Type captureStmtElemTy;
+  if (hasSingleVariable) {
+    if (hasSymMatch) {
+      // Atomic capture construct is of the form [capture-stmt, update-stmt]
+      // FIXME: Emit an implicit cast if there is a type mismatch
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tblah wrote:

If the missing implicit cast can cause a compiler crash then we should add a TODO message so we can fail more gracefully with a useful error message. It would also be better to produce an error message than to generate broken code.

https://github.com/llvm/llvm-project/pull/131603