[flang] [acc] Adding allocation to the recipe of scalar allocatables

[Renaud-K]

Currently the privatization recipe of a scalar allocatable is as follow:

 acc.private.recipe @privatization_ref_box_heap_i32 : !fir.ref<!fir.box<!fir.heap<i32>>> init {
  ^bb0(%arg0: !fir.ref<!fir.box<!fir.heap<i32>>>):
    %0 = fir.alloca !fir.box<!fir.heap<i32>>
    %1:2 = hlfir.declare %0 {uniq_name = "acc.private.init"} : (!fir.ref<!fir.box<!fir.heap<i32>>>) -> (!fir.ref<!fir.box<!fir.heap<i32>>>, !fir.ref<!fir.box<!fir.heap<i32>>>)
    acc.yield %1#0 : !fir.ref<!fir.box<!fir.heap<i32>>>
  }

This change adds the allocation for the scalar.

[llvmbot]

@llvm/pr-subscribers-openacc

@llvm/pr-subscribers-flang-fir-hlfir

Author: Renaud Kauffmann (Renaud-K)

Changes

Currently the privatization recipe of a scalar allocatable is as follow:

 acc.private.recipe @<!-- -->privatization_ref_box_heap_i32 : !fir.ref&lt;!fir.box&lt;!fir.heap&lt;i32&gt;&gt;&gt; init {
  ^bb0(%arg0: !fir.ref&lt;!fir.box&lt;!fir.heap&lt;i32&gt;&gt;&gt;):
    %0 = fir.alloca !fir.box&lt;!fir.heap&lt;i32&gt;&gt;
    %1:2 = hlfir.declare %0 {uniq_name = "acc.private.init"} : (!fir.ref&lt;!fir.box&lt;!fir.heap&lt;i32&gt;&gt;&gt;) -&gt; (!fir.ref&lt;!fir.box&lt;!fir.heap&lt;i32&gt;&gt;&gt;, !fir.ref&lt;!fir.box&lt;!fir.heap&lt;i32&gt;&gt;&gt;)
    acc.yield %1#<!-- -->0 : !fir.ref&lt;!fir.box&lt;!fir.heap&lt;i32&gt;&gt;&gt;
  }

This change adds the allocation for the scalar.

---

Full diff: https://github.com/llvm/llvm-project/pull/154643.diff

2 Files Affected:

• (modified) flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp (+5)
• (modified) flang/test/Lower/OpenACC/acc-private.f90 (+3)

diff --git a/flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp b/flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp
index e5fd19d4622b6..8fefda59806c8 100644
--- a/flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp
+++ b/flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp
@@ -614,6 +614,11 @@ mlir::Value OpenACCMappableModel<Ty>::generatePrivateInit(
     mlir::Type innerTy = fir::unwrapRefType(boxTy.getEleTy());
     if (fir::isa_trivial(innerTy)) {
       retVal = getDeclareOpForType(unwrappedTy).getBase();
+      mlir::Value allocatedScalar =
+          fir::AllocMemOp::create(builder, loc, innerTy);
+      mlir::Value firClass =
+          fir::EmboxOp::create(builder, loc, boxTy, allocatedScalar);
+      fir::StoreOp::create(builder, loc, firClass, retVal);
     } else if (mlir::isa<fir::SequenceType>(innerTy)) {
       hlfir::Entity source = hlfir::Entity{var};
       auto [temp, cleanup] = hlfir::createTempFromMold(loc, firBuilder, source);
diff --git a/flang/test/Lower/OpenACC/acc-private.f90 b/flang/test/Lower/OpenACC/acc-private.f90
index b1bfb02439f03..5ca08a39a1e1c 100644
--- a/flang/test/Lower/OpenACC/acc-private.f90
+++ b/flang/test/Lower/OpenACC/acc-private.f90
@@ -95,6 +95,9 @@
 ! CHECK: ^bb0(%arg0: !fir.ref<!fir.box<!fir.heap<i32>>>):
 ! CHECK:   %[[ALLOCA:.*]] = fir.alloca !fir.box<!fir.heap<i32>>
 ! CHECK:   %[[DECLARE:.*]]:2 = hlfir.declare %[[ALLOCA]] {uniq_name = "acc.private.init"} : (!fir.ref<!fir.box<!fir.heap<i32>>>) -> (!fir.ref<!fir.box<!fir.heap<i32>>>, !fir.ref<!fir.box<!fir.heap<i32>>>)
+! CHECK:   %[[ALLOCMEM:.*]] = fir.allocmem i32
+! CHECK:   %[[BOX:.*]] = fir.embox %[[ALLOCMEM]] : (!fir.heap<i32>) -> !fir.box<!fir.heap<i32>>
+! CHECK:   fir.store %[[BOX]] to %[[DECLARE]]#0 : !fir.ref<!fir.box<!fir.heap<i32>>>
 ! CHECK:   acc.yield %[[DECLARE]]#0 : !fir.ref<!fir.box<!fir.heap<i32>>>
 ! CHECK: }
 

[clementval]

LGTM