[flang][OpenACC] simplify copy and combiner recipe generation

Author: jeanPerier

flang/include/flang/Optimizer/Builder/HLFIRTools.h

@@ -450,6 +450,41 @@ mlir::Value inlineElementalOp(
     mlir::IRMapping &mapper,
     const std::function<bool(hlfir::ElementalOp)> &mustRecursivelyInline);
 
+/// Generate an element-by-element assignment from \p rhs to \p lhs for arrays
+/// that are known not to alias. The assignment is performed using a loop nest
+/// over the optimal extents deduced from both shapes. If \p emitWorkshareLoop
+/// is true, a workshare loop construct may be emitted when available.
+/// Allocatable LHS must be allocated with the right shape and parameters.
+void genNoAliasArrayAssignment(
+    mlir::Location loc, fir::FirOpBuilder &builder, hlfir::Entity rhs,
+    hlfir::Entity lhs, bool emitWorkshareLoop = false,
+    bool temporaryLHS = false,
+    std::function<hlfir::Entity(mlir::Location, fir::FirOpBuilder &,
+                                hlfir::Entity, hlfir::Entity)> *combiner =
+        nullptr);
+
+/// Generate an assignment from \p rhs to \p lhs when they are known not to
+/// alias. Handles both arrays and scalars: for arrays, delegates to
+/// genNoAliasArrayAssignment; for scalars, performs load/store for trivial
+/// scalar types and falls back to hlfir.assign otherwise.
+/// Allocatable LHS must be allocated with the right shape and parameters.
+void genNoAliasAssignment(
+    mlir::Location loc, fir::FirOpBuilder &builder, hlfir::Entity rhs,
+    hlfir::Entity lhs, bool emitWorkshareLoop = false,
+    bool temporaryLHS = false,
+    std::function<hlfir::Entity(mlir::Location, fir::FirOpBuilder &,
+                                hlfir::Entity, hlfir::Entity)> *combiner =
+        nullptr);
+inline void genNoAliasAssignment(
+    mlir::Location loc, fir::FirOpBuilder &builder, hlfir::Entity rhs,
+    hlfir::Entity lhs, bool emitWorkshareLoop, bool temporaryLHS,
+    std::function<hlfir::Entity(mlir::Location, fir::FirOpBuilder &,
+                                hlfir::Entity, hlfir::Entity)>
+        combiner) {
+  genNoAliasAssignment(loc, builder, rhs, lhs, emitWorkshareLoop, temporaryLHS,
+                       &combiner);
+}
+
 /// Create a new temporary with the shape and parameters of the provided
 /// hlfir.eval_in_mem operation and clone the body of the hlfir.eval_in_mem
 /// operating on this new temporary.  returns the temporary and whether the