[flang-commits] [flang] [flang][openacc] Use the same iv privatize value in the loop region (PR #81821)

[Valentin Clement バレンタイン クレメン via flang-commits]

https://github.com/clementval created https://github.com/llvm/llvm-project/pull/81821

IV variable are privatized during acc loop lowering. An hlfir.declare operation is added when mapping the symbol to the new private value. In order to avoid using multiple value in the acc.loop region, we map the symbol to the result of the hlfir.declare operation inserted.

>From 9e65be4502fbfc127a54d2f402116e04f2526cd6 Mon Sep 17 00:00:00 2001
From: Valentin Clement <clementval at gmail.com>
Date: Wed, 14 Feb 2024 20:53:50 -0800
Subject: [PATCH] [flang][openacc] Use the same iv privatize value in the loop
 region

IV variable are privatized during acc loop lowering. An hlfir.declare
operation is added when mapping the symbol to the new private value.
In order to avoid using multiple value in the acc.loop region, we map
the symbol to the result of the hlfir.declare operation inserted.
---
 flang/lib/Lower/OpenACC.cpp              | 10 +++++++++-
 flang/test/Lower/OpenACC/acc-private.f90 | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/flang/lib/Lower/OpenACC.cpp b/flang/lib/Lower/OpenACC.cpp
index 6ae270f63f5cf4..446b1529ca0088 100644
--- a/flang/lib/Lower/OpenACC.cpp
+++ b/flang/lib/Lower/OpenACC.cpp
@@ -1658,10 +1658,18 @@ static void privatizeIv(Fortran::lower::AbstractConverter &converter,
       mlir::acc::DataClause::acc_private, ivValue.getType());
 
   privateOperands.push_back(op.getAccPtr());
-  ivPrivate.push_back(op.getAccPtr());
   privatizations.push_back(mlir::SymbolRefAttr::get(builder.getContext(),
                                                     recipe.getSymName().str()));
+
+  // Map the new private iv to its symbol for the scope of the loop. bindSymbol
+  // might create a hlfir.declare op, if so, we map its result in order to
+  // use the sym value in the scope.
   converter.bindSymbol(sym, op.getAccPtr());
+  auto privateValue = converter.getSymbolAddress(sym);
+  if (auto declareOp =
+          mlir::dyn_cast<hlfir::DeclareOp>(privateValue.getDefiningOp()))
+    privateValue = declareOp.getResults()[0];
+  ivPrivate.push_back(privateValue);
 }
 
 static mlir::acc::LoopOp
diff --git a/flang/test/Lower/OpenACC/acc-private.f90 b/flang/test/Lower/OpenACC/acc-private.f90
index 29074cbaedc910..ba582d40f0f512 100644
--- a/flang/test/Lower/OpenACC/acc-private.f90
+++ b/flang/test/Lower/OpenACC/acc-private.f90
@@ -382,3 +382,22 @@ subroutine sub1()
 end module
 
 ! CHECK: acc.parallel private(@privatization_ref_10xf32 -> %{{.*}} : !fir.ref<!fir.array<10xf32>>)
+
+subroutine acc_private_use()
+  integer :: i, j
+
+  !$acc parallel loop
+  do i = 1, 10
+    j = i
+  end do
+end
+
+! CHECK-LABEL: func.func @_QPacc_private_use()
+! CHECK: %[[I:.*]] = fir.alloca i32 {bindc_name = "i", uniq_name = "_QFacc_private_useEi"}
+! CHECK: %[[DECL_I:.*]]:2 = hlfir.declare %0 {uniq_name = "_QFacc_private_useEi"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK: acc.parallel
+! CHECK: %[[PRIV_I:.*]] = acc.private varPtr(%[[DECL_I]]#1 : !fir.ref<i32>) -> !fir.ref<i32> {implicit = true, name = ""}
+! CHECK: %[[DECL_PRIV_I:.*]]:2 = hlfir.declare %[[PRIV_I]] {uniq_name = "_QFacc_private_useEi"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK: acc.loop private(@privatization_ref_i32 -> %[[PRIV_I]] : !fir.ref<i32>) control(%[[IV0:.*]] : i32) = (%c1{{.*}} : i32) to (%c10{{.*}} : i32) step (%c1{{.*}} : i32)
+! CHECK:   fir.store %[[IV0]] to %[[DECL_PRIV_I]]#0 : !fir.ref<i32>
+! CHECK:   %{{.*}} = fir.load %[[DECL_PRIV_I]]#0 : !fir.ref<i32>