[PATCH] D119429: [flang] Lower simple RETURN statement

[Valentin Clement via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG85b89ed213c4: [flang] Lower simple RETURN statement (authored by clementval).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119429/new/

https://reviews.llvm.org/D119429

Files:
  flang/lib/Lower/Bridge.cpp
  flang/test/Lower/return-statement.f90


Index: flang/test/Lower/return-statement.f90
===================================================================
--- /dev/null
+++ flang/test/Lower/return-statement.f90
@@ -0,0 +1,34 @@
+! RUN: bbc %s -o "-" -emit-fir | FileCheck %s
+
+program basic
+  return
+end program
+
+! CHECK-LABEL: func @_QQmain() {
+! CHECK:         return
+! CHECK:       }
+
+subroutine sub1()
+  return
+end
+
+! CHECK-LABEL: func @_QPsub1() {
+! CHECK:         cf.br ^bb1
+! CHECK:       ^bb1:  // pred: ^bb0
+! CHECK:         return
+
+subroutine sub2()
+  goto 3
+  2 return
+  3 goto 2
+end
+
+! CHECK-LABEL: func @_QPsub2() {
+! CHECK:         cf.br ^bb2
+! CHECK:       ^bb1:  // pred: ^bb2
+! CHECK:         cf.br ^bb3
+! CHECK:       ^bb2:  // pred: ^bb0
+! CHECK:         cf.br ^bb1
+! CHECK:       ^bb3:  // pred: ^bb1
+! CHECK:         return
+
Index: flang/lib/Lower/Bridge.cpp
===================================================================
--- flang/lib/Lower/Bridge.cpp
+++ flang/lib/Lower/Bridge.cpp
@@ -337,6 +337,13 @@
 
   void genFIRProcedureExit(Fortran::lower::pft::FunctionLikeUnit &funit,
                            const Fortran::semantics::Symbol &symbol) {
+    if (mlir::Block *finalBlock = funit.finalBlock) {
+      // The current block must end with a terminator.
+      if (blockIsUnterminated())
+        builder->create<mlir::cf::BranchOp>(toLocation(), finalBlock);
+      // Set insertion point to final block.
+      builder->setInsertionPoint(finalBlock, finalBlock->end());
+    }
     if (Fortran::semantics::IsFunction(symbol)) {
       TODO(toLocation(), "Function lowering");
     } else {
@@ -652,7 +659,24 @@
   }
 
   void genFIR(const Fortran::parser::ReturnStmt &stmt) {
-    TODO(toLocation(), "ReturnStmt lowering");
+    Fortran::lower::pft::FunctionLikeUnit *funit =
+        getEval().getOwningProcedure();
+    assert(funit && "not inside main program, function or subroutine");
+    if (funit->isMainProgram()) {
+      genExitRoutine();
+      return;
+    }
+    mlir::Location loc = toLocation();
+    if (stmt.v) {
+      TODO(loc, "Alternate return statement");
+    }
+    // Branch to the last block of the SUBROUTINE, which has the actual return.
+    if (!funit->finalBlock) {
+      mlir::OpBuilder::InsertPoint insPt = builder->saveInsertionPoint();
+      funit->finalBlock = builder->createBlock(&builder->getRegion());
+      builder->restoreInsertionPoint(insPt);
+    }
+    builder->create<mlir::cf::BranchOp>(loc, funit->finalBlock);
   }
 
   void genFIR(const Fortran::parser::CycleStmt &) {


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