[flang][openacc] Lower init and shutdown directive

[clementval]

Summary

This patch upstream the lowering of Init and Shutdown directives that was initially done in
https://github.com/flang-compiler/f18-llvm-project/pull/529

[clementval]

Rebase

[mehdi_amini]

Do you have tests for this?

[clementval]

In D90488#2414718, @mehdi_amini wrote:

Do you have tests for this?

Test still live in the fir-dev branch. Since not all the infra is present for the test to be executed, there were not upstreamed yet. the rest of the fir-dev branch should be upstream very soon but I can hardly influence that.

[mehdi_amini]

In D90488#2414751, @clementval wrote:

In D90488#2414718, @mehdi_amini wrote:

Do you have tests for this?

Test still live in the fir-dev branch. Since not all the infra is present for the test to be executed, there were not upstreamed yet. the rest of the fir-dev branch should be upstream very soon but I can hardly influence that.

I'd like to see IR -> IR unit-test (mlir-opt style) provided here. I don't think it is reasonable to upstream code without proper testing.

[clementval]

In D90488#2414789, @mehdi_amini wrote:

In D90488#2414751, @clementval wrote:

In D90488#2414718, @mehdi_amini wrote:

Do you have tests for this?

Test still live in the fir-dev branch. Since not all the infra is present for the test to be executed, there were not upstreamed yet. the rest of the fir-dev branch should be upstream very soon but I can hardly influence that.

I'd like to see IR -> IR unit-test (mlir-opt style) provided here. I don't think it is reasonable to upstream code without proper testing.

There are IR to IR test for those operations in mlir itself where the dialect is located.

All OpenMP and OpenACC lowering are waiting on the fir-dev to be upstream.

So should we un-upstream the code for the time being?

[mehdi_amini]

In D90488#2414856, @clementval wrote:

All OpenMP and OpenACC lowering are waiting on the fir-dev to be upstream.

Is this "dead code" right now then?

So should we un-upstream the code for the time being?

If this can't be tested / is dead code, I'm not super comfortable having this in-tree. What is the plan for fir-dev development to move upstream, I'm still quite puzzled and don't understand why the development does not happen in tree, I think I asked on the mailing list but never got an answer.

[clementval]

In D90488#2414920, @mehdi_amini wrote:

If this can't be tested / is dead code, I'm not super comfortable having this in-tree. What is the plan for fir-dev development to move upstream, I'm still quite puzzled and don't understand why the development does not happen in tree, I think I asked on the mailing list but never got an answer.

There was discussion on the last few calls to move it upstream very soon. A RFC should have been sent to coordinate the upstreaming of the fir-dev patch(es). Looks like it hasn't moved yet. @kiranchandramohan @SouraVX @schweitz @sscalpone Do you know if there is any progress with the upstreaming process?

@mehdi_amini I'm fine with removing this code can be upstream again later if you prefer. Same with all the code in flang/lib/Lower/OpenACC.cpp.

The tests have been created and they are ready to be upstreamed as soon as I can (https://github.com/flang-compiler/f18-llvm-project/tree/fir-dev/flang/test/Lower/OpenACC)

[mehdi_amini]

I'm fine with leaving it there for now, looking forward to see everything upstream!

[clementval]

In D90488#2415007, @mehdi_amini wrote:

I'm fine with leaving it there for now, looking forward to see everything upstream!

Thanks! Agreed it isn't ideal for the moment.

[SouraVX]

There was discussion on the last few calls to move it upstream very soon. A RFC should have been sent to coordinate the upstreaming of the fir-dev patch(es). Looks like it hasn't moved yet. @kiranchandramohan @SouraVX @schweitz @sscalpone Do you know if there is any progress with the upstreaming process?

AFAIK(based on @jdoerfert comment in our last meet) it's up for internal review for Lab folks.

flang/lib/Lower/OpenACC.cpp

genACCExitDataOp(Fortran::lower::AbstractConverter &converter,
   if (addAsyncAttr)
     exitDataOp.asyncAttr(firOpBuilder.getUnitAttr());
   if (addWaitAttr)
     exitDataOp.waitAttr(firOpBuilder.getUnitAttr());
   if (addFinalizeAttr)
     exitDataOp.finalizeAttr(firOpBuilder.getUnitAttr());
 }
 
+template <typename Op>
+static void
+genACCInitShutdownOp(Fortran::lower::AbstractConverter &converter,
+                     const Fortran::parser::AccClauseList &accClauseList) {
+  mlir::Value ifCond, deviceNum;
+  SmallVector<Value, 2> deviceTypeOperands;
+
+  auto &firOpBuilder = converter.getFirOpBuilder();
+  auto currentLocation = converter.getCurrentLocation();
+
+  // Lower clauses values mapped to operands.
+  // Keep track of each group of operands separatly as clauses can appear
+  // more than once.
+  for (const auto &clause : accClauseList.v) {
+    if (const auto *ifClause =
+            std::get_if<Fortran::parser::AccClause::If>(&clause.u)) {
+      mlir::Value cond = fir::getBase(
+          converter.genExprValue(*Fortran::semantics::GetExpr(ifClause->v)));
+      ifCond = firOpBuilder.createConvert(currentLocation,
+                                          firOpBuilder.getI1Type(), cond);
+    } else if (const auto *deviceNumClause =
+                   std::get_if<Fortran::parser::AccClause::DeviceNum>(
+                       &clause.u)) {
+      deviceNum = fir::getBase(converter.genExprValue(
+          *Fortran::semantics::GetExpr(deviceNumClause->v)));
+    } else if (const auto *deviceTypeClause =
+                   std::get_if<Fortran::parser::AccClause::DeviceType>(
+                       &clause.u)) {
+
+      const auto &deviceTypeValue = deviceTypeClause->v;
+      if (deviceTypeValue) {
+        for (const auto &scalarIntExpr : *deviceTypeValue) {
+          mlir::Value expr = fir::getBase(converter.genExprValue(
+              *Fortran::semantics::GetExpr(scalarIntExpr)));
+          deviceTypeOperands.push_back(expr);
+        }
+      } else {
+        // * was passed as value and will be represented as a -1 constant
+        // integer.
+        mlir::Value star = firOpBuilder.createIntegerConstant(
+            currentLocation, firOpBuilder.getIntegerType(32), /* STAR */ -1);
+        deviceTypeOperands.push_back(star);
+      }
+    }
+  }
+
+  // Prepare the operand segement size attribute and the operands value range.
+  SmallVector<mlir::Value, 6> operands;
+  SmallVector<int32_t, 3> operandSegments;
+  addOperands(operands, operandSegments, deviceTypeOperands);
+  addOperand(operands, operandSegments, deviceNum);
+  addOperand(operands, operandSegments, ifCond);
+
+  createSimpleOp<Op>(firOpBuilder, currentLocation, operands, operandSegments);
+}
+
 static void
 genACC(Fortran::lower::AbstractConverter &converter,
        Fortran::lower::pft::Evaluation &eval,
        const Fortran::parser::OpenACCStandaloneConstruct &standaloneConstruct) {
   const auto &standaloneDirective =
       std::get<Fortran::parser::AccStandaloneDirective>(standaloneConstruct.t);
   const auto &accClauseList =
       std::get<Fortran::parser::AccClauseList>(standaloneConstruct.t);
 
   if (standaloneDirective.v == llvm::acc::Directive::ACCD_enter_data) {
     TODO("OpenACC enter data directive not lowered yet!");
   } else if (standaloneDirective.v == llvm::acc::Directive::ACCD_exit_data) {
     genACCExitDataOp(converter, accClauseList);
   } else if (standaloneDirective.v == llvm::acc::Directive::ACCD_init) {
-    TODO("OpenACC init directive not lowered yet!");
+    genACCInitShutdownOp<mlir::acc::InitOp>(converter, accClauseList);
   } else if (standaloneDirective.v == llvm::acc::Directive::ACCD_shutdown) {
-    TODO("OpenACC shutdown directive not lowered yet!");
+    genACCInitShutdownOp<mlir::acc::ShutdownOp>(converter, accClauseList);
   } else if (standaloneDirective.v == llvm::acc::Directive::ACCD_set) {
     TODO("OpenACC set directive not lowered yet!");
   } else if (standaloneDirective.v == llvm::acc::Directive::ACCD_update) {
     TODO("OpenACC update directive not lowered yet!");
   }
 }
 
 void Fortran::lower::genOpenACCConstruct(