[OpenACC][CIR] Implement 'gang' lowering on `routine'

This is a bit more work than the worker/vector/seq in that gang takes an
optional `dim` argument.  The argument is always 1, 2, or 3
(constants!), and the other argument-types that gang allows elsewhere
aren't valid here.

For the IR, we had to add 2 overloads of `addGang`.  The first just adds
the 'valueless' one, which can just add to the one ArrayAttr.  The
second has to add to TWO lists.

Note: The standard limits to only 1 `gang` per construct.  We decided
after evaluating it, that it really means 'per device-type region'.
However, device_type isn't implemented yet, so we'll add tests for that
when we do.

At the moment, we added the device_type infrastructure however.

Author: erichkeane

clang/lib/CIR/CodeGen/CIRGenDeclOpenACC.cpp

@@ -303,14 +303,16 @@ void CIRGenModule::emitGlobalOpenACCRoutineDecl(const OpenACCRoutineDecl *d) {
 namespace {
 class OpenACCRoutineClauseEmitter final
     : public OpenACCClauseVisitor<OpenACCRoutineClauseEmitter> {
+      CIRGenModule &cgm;
   CIRGen::CIRGenBuilderTy &builder;
   mlir::acc::RoutineOp routineOp;
   llvm::SmallVector<mlir::acc::DeviceType> lastDeviceTypeValues;
 
 public:
-  OpenACCRoutineClauseEmitter(CIRGen::CIRGenBuilderTy &builder,
+  OpenACCRoutineClauseEmitter(CIRGenModule &cgm,
+                              CIRGen::CIRGenBuilderTy &builder,
                               mlir::acc::RoutineOp routineOp)
-      : builder(builder), routineOp(routineOp) {}
+      : cgm(cgm), builder(builder), routineOp(routineOp) {}
 
   void emitClauses(ArrayRef<const OpenACCClause *> clauses) {
     this->VisitClauseList(clauses);
@@ -333,6 +335,26 @@ class OpenACCRoutineClauseEmitter final
   void VisitNoHostClause(const OpenACCNoHostClause &clause) {
     routineOp.setNohost(/*attrValue=*/true);
   }
+
+  void VisitGangClause(const OpenACCGangClause &clause) {
+    // Gang has an optional 'dim' value, which is a constant int of 1, 2, or 3.
+    // If we don't store any expressions in the clause, there are none, else we
+    // expect there is 1, since Sema should enforce that the single 'dim' is the
+    // only valid value.
+    if (clause.getNumExprs() == 0) {
+      routineOp.addGang(builder.getContext(), lastDeviceTypeValues);
+    } else {
+      assert(clause.getNumExprs() == 1);
+      auto [kind, expr] = clause.getExpr(0);
+      assert(kind == OpenACCGangKind::Dim);
+
+      llvm::APSInt curValue = expr->EvaluateKnownConstInt(cgm.getASTContext());
+      // The value is 1, 2, or 3, but 64 bit seems right enough.
+      curValue = curValue.sextOrTrunc(64);
+      routineOp.addGang(builder.getContext(), lastDeviceTypeValues,
+                        curValue.getZExtValue());
+    }
+  }
 };
 } // namespace
 
@@ -373,6 +395,6 @@ void CIRGenModule::emitOpenACCRoutineDecl(
       mlir::acc::getRoutineInfoAttrName(),
       mlir::acc::RoutineInfoAttr::get(func.getContext(), funcRoutines));
 
-  OpenACCRoutineClauseEmitter emitter{builder, routineOp};
+  OpenACCRoutineClauseEmitter emitter{*this, builder, routineOp};
   emitter.emitClauses(clauses);
 }

clang/test/CIR/CodeGenOpenACC/routine-clauses.cpp

@@ -18,6 +18,27 @@ void Func5() {}
 void Func6() {}
 #pragma acc routine(Func6) nohost vector
 
+#pragma acc routine gang
+void Func7() {}
+
+void Func8() {}
+#pragma acc routine(Func8) gang
+
+#pragma acc routine gang(dim:1)
+void Func9() {}
+
+void Func10() {}
+#pragma acc routine(Func10) gang(dim:3)
+
+constexpr int Value = 2;
+
+#pragma acc routine gang(dim:Value) nohost
+void Func11() {}
+
+
+void Func12() {}
+#pragma acc routine(Func12) nohost gang(dim:Value)
+
 // CHECK: cir.func{{.*}} @[[F1_NAME:.*Func1[^\(]*]]({{.*}}){{.*}} attributes {acc.routine_info = #acc.routine_info<[@[[F1_R_NAME:.*]]]>}
 // CHECK: acc.routine @[[F1_R_NAME]] func(@[[F1_NAME]]) seq nohost
 
@@ -32,7 +53,25 @@ void Func6() {}
 // CHECK: acc.routine @[[F5_R_NAME]] func(@[[F5_NAME]]) vector
 
 // CHECK: cir.func{{.*}} @[[F6_NAME:.*Func6[^\(]*]]({{.*}}){{.*}} attributes {acc.routine_info = #acc.routine_info<[@[[F6_R_NAME:.*]]]>}
+//
+// CHECK: cir.func{{.*}} @[[F7_NAME:.*Func7[^\(]*]]({{.*}}){{.*}} attributes {acc.routine_info = #acc.routine_info<[@[[F7_R_NAME:.*]]]>}
+// CHECK: acc.routine @[[F7_R_NAME]] func(@[[F7_NAME]]) gang
+//
+// CHECK: cir.func{{.*}} @[[F8_NAME:.*Func8[^\(]*]]({{.*}}){{.*}} attributes {acc.routine_info = #acc.routine_info<[@[[F8_R_NAME:.*]]]>}
+//
+// CHECK: cir.func{{.*}} @[[F9_NAME:.*Func9[^\(]*]]({{.*}}){{.*}} attributes {acc.routine_info = #acc.routine_info<[@[[F9_R_NAME:.*]]]>}
+// CHECK: acc.routine @[[F9_R_NAME]] func(@[[F9_NAME]]) gang(dim: 1 : i64)
+//
+// CHECK: cir.func{{.*}} @[[F10_NAME:.*Func10[^\(]*]]({{.*}}){{.*}} attributes {acc.routine_info = #acc.routine_info<[@[[F10_R_NAME:.*]]]>}
+
+// CHECK: cir.func{{.*}} @[[F11_NAME:.*Func11[^\(]*]]({{.*}}){{.*}} attributes {acc.routine_info = #acc.routine_info<[@[[F11_R_NAME:.*]]]>}
+// CHECK: acc.routine @[[F11_R_NAME]] func(@[[F11_NAME]]) gang(dim: 2 : i64)
+//
+// CHECK: cir.func{{.*}} @[[F12_NAME:.*Func12[^\(]*]]({{.*}}){{.*}} attributes {acc.routine_info = #acc.routine_info<[@[[F12_R_NAME:.*]]]>}
 
 // CHECK: acc.routine @[[F2_R_NAME]] func(@[[F2_NAME]]) seq
 // CHECK: acc.routine @[[F4_R_NAME]] func(@[[F4_NAME]]) worker nohost
 // CHECK: acc.routine @[[F6_R_NAME]] func(@[[F6_NAME]]) vector nohost
+// CHECK: acc.routine @[[F8_R_NAME]] func(@[[F8_NAME]]) gang
+// CHECK: acc.routine @[[F10_R_NAME]] func(@[[F10_NAME]]) gang(dim: 3 : i64)
+// CHECK: acc.routine @[[F12_R_NAME]] func(@[[F12_NAME]]) gang(dim: 2 : i64)

mlir/include/mlir/Dialect/OpenACC/OpenACCOps.td

@@ -3286,6 +3286,11 @@ def OpenACC_RoutineOp : OpenACC_Op<"routine", [IsolatedFromAbove]> {
     void addVector(MLIRContext *, llvm::ArrayRef<DeviceType>);
     // Add an entry to the 'worker' attribute for each additional device types.
     void addWorker(MLIRContext *, llvm::ArrayRef<DeviceType>);
+    // Add an entry to the 'gang' attribute for each additional device type.
+    void addGang(MLIRContext *, llvm::ArrayRef<DeviceType>);
+    // Add an entry to the 'gang' attribute with a value for each additional
+    // device type.
+    void addGang(MLIRContext *, llvm::ArrayRef<DeviceType>, uint64_t);
   }];
 
   let assemblyFormat = [{

mlir/lib/Dialect/OpenACC/IR/OpenACC.cpp

@@ -4367,6 +4367,43 @@ void RoutineOp::addWorker(MLIRContext *context,
                                                    effectiveDeviceTypes));
 }
 
+void RoutineOp::addGang(MLIRContext *context,
+                          llvm::ArrayRef<DeviceType> effectiveDeviceTypes) {
+  setGangAttr(addDeviceTypeAffectedOperandHelper(context, getGangAttr(),
+                                                 effectiveDeviceTypes));
+}
+
+void RoutineOp::addGang(MLIRContext *context,
+                        llvm::ArrayRef<DeviceType> effectiveDeviceTypes,
+                        uint64_t val) {
+  llvm::SmallVector<mlir::Attribute> dimValues;
+  llvm::SmallVector<mlir::Attribute> deviceTypes;
+
+  if (getGangDimAttr())
+    llvm::copy(getGangDimAttr(), std::back_inserter(dimValues));
+  if (getGangDimDeviceTypeAttr())
+    llvm::copy(getGangDimDeviceTypeAttr(), std::back_inserter(deviceTypes));
+
+  assert(dimValues.size() == deviceTypes.size());
+
+  if (effectiveDeviceTypes.empty()) {
+    dimValues.push_back(
+        mlir::IntegerAttr::get(mlir::IntegerType::get(context, 64), val));
+    deviceTypes.push_back(
+        acc::DeviceTypeAttr::get(context, acc::DeviceType::None));
+  } else {
+    for (DeviceType dt : effectiveDeviceTypes) {
+    dimValues.push_back(
+        mlir::IntegerAttr::get(mlir::IntegerType::get(context, 64), val));
+      deviceTypes.push_back(acc::DeviceTypeAttr::get(context, dt));
+    }
+  }
+  assert(dimValues.size() == deviceTypes.size());
+
+  setGangDimAttr(mlir::ArrayAttr::get(context, dimValues));
+  setGangDimDeviceTypeAttr(mlir::ArrayAttr::get(context, deviceTypes));
+}
+
 //===----------------------------------------------------------------------===//
 // InitOp
 //===----------------------------------------------------------------------===//