[mlir][OpenMP] Add order clause definition to simd construct

[domada]

Summary

Update simd construct definition and add mlir tests to prove that order(concurrent) clause is correctly modeled for simd construct.

[raghavendhra]

LGTM

[kiranchandramohan]

LGTM.

mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td

397

[domada]

Patch rebased

[domada]

Patch is committed. Link to the commit: https://github.com/llvm/llvm-project/commit/163dbfe869f550bd2d22520fda109876a1122eda . I forgot to add review link in commit message.

flang/lib/Lower/OpenMP.cpp

static void genOMP(Fortran::lower::AbstractConverter &converter,
   }
 
   // 2.9.3.1 SIMD construct
   // TODO: Support all the clauses
   if (llvm::omp::OMPD_simd == ompDirective) {
     TypeRange resultType;
     auto SimdLoopOp = firOpBuilder.create<mlir::omp::SimdLoopOp>(
         currentLocation, resultType, lowerBound, upperBound, step, alignedVars,
-        nullptr, ifClauseOperand, simdlenClauseOperand, safelenClauseOperand,
+        nullptr, ifClauseOperand,
+        orderClauseOperand.dyn_cast_or_null<omp::ClauseOrderKindAttr>(),
+        simdlenClauseOperand, safelenClauseOperand,
         /*inclusive=*/firOpBuilder.getUnitAttr());
     createBodyOfOp<omp::SimdLoopOp>(SimdLoopOp, converter, currentLocation,
                                     eval, &loopOpClauseList, iv);
     return;
   }
 
   // FIXME: Add support for following clauses:
   // 1. linear

mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td

let description = [{
     The `alignment_values` attribute additionally specifies alignment of each
     corresponding aligned operand. Note that `$aligned_vars` and
     `alignment_values` should contain the same number of elements.
 
     When an if clause is present and evaluates to false, the preferred number of
     iterations to be executed concurrently is one, regardless of whether
     a simdlen clause is specified.
 
+    The optional `order` attribute specifies which order the iterations of the
+    associate loops are executed in. Currently the only option for this
+    attribute is "concurrent".
+
     When a simdlen clause is present, the preferred number of iterations to be
     executed concurrently is the value provided to the simdlen clause.
 
     The safelen clause specifies that no two concurrent iterations within a
     SIMD chunk can have a distance in the logical iteration space that is
     greater than or equal to the value given in the clause.
     ```
     omp.simdloop <clauses>
     for (%i1, %i2) : index = (%c0, %c0) to (%c10, %c10) step (%c1, %c1) {
       // block operations
       omp.yield
     }
     ```
   }];
 
   // TODO: Add other clauses
   let arguments = (ins Variadic<IntLikeType>:$lowerBound,
              Variadic<IntLikeType>:$upperBound,
              Variadic<IntLikeType>:$step,
              Variadic<OpenMP_PointerLikeType>:$aligned_vars,
              OptionalAttr<I64ArrayAttr>:$alignment_values,
              Optional<I1>:$if_expr,
+             OptionalAttr<OrderKindAttr>:$order_val,
              ConfinedAttr<OptionalAttr<I64Attr>, [IntPositive]>:$simdlen,
              ConfinedAttr<OptionalAttr<I64Attr>, [IntPositive]>:$safelen,
              UnitAttr:$inclusive
      );
 
   let regions = (region AnyRegion:$region);
   let assemblyFormat = [{
     oilist(`aligned` `(`
               custom<AlignedClause>($aligned_vars, type($aligned_vars),
                                    $alignment_values) `)`
           |`if` `(` $if_expr `)`
+          |`order` `(` custom<ClauseAttr>($order_val) `)`
           |`simdlen` `(` $simdlen  `)`
           |`safelen` `(` $safelen  `)`
     ) `for` custom<LoopControl>($region, $lowerBound, $upperBound, $step,
                                   type($step), $inclusive) attr-dict
   }];
 
   let extraClassDeclaration = [{
     /// Returns the number of loops in the simd loop nest.

mlir/test/Dialect/OpenMP/invalid.mlir

"omp.simdloop"(%arg0, %arg1, %arg2, %arg3, %arg3) ({
     ^bb0(%arg5: index):
       "omp.yield"() : () -> ()
   }) {alignment_values = [1, 128], operand_segment_sizes = array<i32: 1, 1, 1,2, 0>} : (index, index, index, memref<i32>, memref<i32>) -> ()
   return
 }
 
 // -----
 
+func.func @omp_simdloop_order_value(%lb : index, %ub : index, %step : index) {
+  // expected-error @below {{invalid clause value: 'default'}}
+  omp.simdloop order(default) for (%iv): index = (%lb) to (%ub) step (%step) {
+    omp.yield
+  }
+  return
+}
+
+// -----
+
 func.func @omp_simdloop_pretty_simdlen(%lb : index, %ub : index, %step : index) -> () {
   // expected-error @below {{op attribute 'simdlen' failed to satisfy constraint: 64-bit signless integer attribute whose value is positive}}
   omp.simdloop simdlen(0) for (%iv): index = (%lb) to (%ub) step (%step) {
     omp.yield
   }
   return
 }
 

mlir/test/Dialect/OpenMP/ops.mlir

 func.func @omp_simdloop_pretty_if(%lb : index, %ub : index, %step : index, %if_cond : i1) -> () {
   // CHECK: omp.simdloop if(%{{.*}}) for (%{{.*}}) : index = (%{{.*}}) to (%{{.*}}) step (%{{.*}})
   omp.simdloop if(%if_cond) for (%iv): index = (%lb) to (%ub) step (%step) {
     omp.yield
   }
   return
 }
 
+// CHECK-LABEL: omp_simdloop_pretty_order
+func.func @omp_simdloop_pretty_order(%lb : index, %ub : index, %step : index) -> () {
+  // CHECK: omp.simdloop order(concurrent)
+  // CHECK-SAME: for (%{{.*}}) : index = (%{{.*}}) to (%{{.*}}) step (%{{.*}})
+  omp.simdloop order(concurrent) for (%iv): index = (%lb) to (%ub) step (%step) {
+    omp.yield
+  }
+  return
+}
+
 // CHECK-LABEL: omp_simdloop_pretty_simdlen
 func.func @omp_simdloop_pretty_simdlen(%lb : index, %ub : index, %step : index) -> () {
   // CHECK: omp.simdloop simdlen(2) for (%{{.*}}) : index = (%{{.*}}) to (%{{.*}}) step (%{{.*}})
   omp.simdloop simdlen(2) for (%iv): index = (%lb) to (%ub) step (%step) {
     omp.yield
   }
   return
 }