[flang-commits] [flang] [mlir] [Flang][MLIR] Add `!$omp unroll` and `omp.unroll_heuristic` (PR #144785)

[Kareem Ergawy via flang-commits]

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@@ -2128,6 +2128,161 @@ genLoopOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
   return loopOp;
 }
 
+static mlir::omp::CanonicalLoopOp
+genCanonicalLoopOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
+                   semantics::SemanticsContext &semaCtx,
+                   lower::pft::Evaluation &eval, mlir::Location loc,
+                   const ConstructQueue &queue,
+                   ConstructQueue::const_iterator item,
+                   llvm::ArrayRef<const semantics::Symbol *> ivs,
+                   llvm::omp::Directive directive, DataSharingProcessor &dsp) {
+  fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
+
+  assert(ivs.size() == 1 && "Nested loops not yet implemented");
+  const semantics::Symbol *iv = ivs[0];
+
+  auto &nestedEval = eval.getFirstNestedEvaluation();
+  if (nestedEval.getIf<parser::DoConstruct>()->IsDoConcurrent()) {
+    TODO(loc, "Do Concurrent in unroll construct");
+  }
+
+  // Get the loop bounds (and increment)
+  auto &doLoopEval = nestedEval.getFirstNestedEvaluation();
+  auto *doStmt = doLoopEval.getIf<parser::NonLabelDoStmt>();
+  assert(doStmt && "Expected do loop to be in the nested evaluation");
+  auto &loopControl = std::get<std::optional<parser::LoopControl>>(doStmt->t);
+  assert(loopControl.has_value());
+  auto *bounds = std::get_if<parser::LoopControl::Bounds>(&loopControl->u);
+  assert(bounds && "Expected bounds for canonical loop");
+  lower::StatementContext stmtCtx;
+  mlir::Value loopLBVar = fir::getBase(
+      converter.genExprValue(*semantics::GetExpr(bounds->lower), stmtCtx));
+  mlir::Value loopUBVar = fir::getBase(
+      converter.genExprValue(*semantics::GetExpr(bounds->upper), stmtCtx));
+  mlir::Value loopStepVar = [&]() {
+    if (bounds->step) {
+      return fir::getBase(
+          converter.genExprValue(*semantics::GetExpr(bounds->step), stmtCtx));
+    } else {
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ergawy wrote:

nit: no need for the `else` here.

https://github.com/llvm/llvm-project/pull/144785