[flang-commits] [flang] [flang][OpenMP] Support delayed privatisation for composite do simd (PR #150979)

[Kajetan Puchalski via flang-commits]

https://github.com/mrkajetanp updated https://github.com/llvm/llvm-project/pull/150979

>From b6b6c9854696e08a1eac7be65f5a6839399b67d4 Mon Sep 17 00:00:00 2001
From: Kajetan Puchalski <kajetan.puchalski at arm.com>
Date: Mon, 28 Jul 2025 13:23:37 +0000
Subject: [PATCH] [flang][OpenMP] Support delayed privatisation for composite
 do simd

Implement the lowering for delayed privatisation for composite "do simd"
constructs. Fixes new crashes previously masked by simd information on
composite constructs being ignored, such as llvm#150975.

Signed-off-by: Kajetan Puchalski <kajetan.puchalski at arm.com>
---
 flang/lib/Lower/OpenMP/OpenMP.cpp       | 23 +++++++++++++++--------
 flang/test/Lower/OpenMP/wsloop-simd.f90 | 21 ++++++++++++++++++++-
 2 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/flang/lib/Lower/OpenMP/OpenMP.cpp b/flang/lib/Lower/OpenMP/OpenMP.cpp
index 12089d6caa5fe..416676485cb56 100644
--- a/flang/lib/Lower/OpenMP/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP/OpenMP.cpp
@@ -3200,11 +3200,16 @@ static mlir::omp::WsloopOp genCompositeDoSimd(
   genSimdClauses(converter, semaCtx, simdItem->clauses, loc, simdClauseOps,
                  simdReductionSyms);
 
-  // TODO: Support delayed privatization.
-  DataSharingProcessor dsp(converter, semaCtx, simdItem->clauses, eval,
-                           /*shouldCollectPreDeterminedSymbols=*/true,
-                           /*useDelayedPrivatization=*/false, symTable);
-  dsp.processStep1();
+  DataSharingProcessor wsloopItemDSP(
+      converter, semaCtx, doItem->clauses, eval,
+      /*shouldCollectPreDeterminedSymbols=*/false,
+      /*useDelayedPrivatization=*/true, symTable);
+  wsloopItemDSP.processStep1(&wsloopClauseOps);
+
+  DataSharingProcessor simdItemDSP(converter, semaCtx, simdItem->clauses, eval,
+                                   /*shouldCollectPreDeterminedSymbols=*/true,
+                                   /*useDelayedPrivatization=*/true, symTable);
+  simdItemDSP.processStep1(&simdClauseOps);
 
   // Pass the innermost leaf construct's clauses because that's where COLLAPSE
   // is placed by construct decomposition.
@@ -3215,7 +3220,8 @@ static mlir::omp::WsloopOp genCompositeDoSimd(
 
   // Operation creation.
   EntryBlockArgs wsloopArgs;
-  // TODO: Add private syms and vars.
+  wsloopArgs.priv.syms = wsloopItemDSP.getDelayedPrivSymbols();
+  wsloopArgs.priv.vars = wsloopClauseOps.privateVars;
   wsloopArgs.reduction.syms = wsloopReductionSyms;
   wsloopArgs.reduction.vars = wsloopClauseOps.reductionVars;
   auto wsloopOp = genWrapperOp<mlir::omp::WsloopOp>(
@@ -3223,7 +3229,8 @@ static mlir::omp::WsloopOp genCompositeDoSimd(
   wsloopOp.setComposite(/*val=*/true);
 
   EntryBlockArgs simdArgs;
-  // TODO: Add private syms and vars.
+  simdArgs.priv.syms = simdItemDSP.getDelayedPrivSymbols();
+  simdArgs.priv.vars = simdClauseOps.privateVars;
   simdArgs.reduction.syms = simdReductionSyms;
   simdArgs.reduction.vars = simdClauseOps.reductionVars;
   auto simdOp =
@@ -3233,7 +3240,7 @@ static mlir::omp::WsloopOp genCompositeDoSimd(
   genLoopNestOp(converter, symTable, semaCtx, eval, loc, queue, simdItem,
                 loopNestClauseOps, iv,
                 {{wsloopOp, wsloopArgs}, {simdOp, simdArgs}},
-                llvm::omp::Directive::OMPD_do_simd, dsp);
+                llvm::omp::Directive::OMPD_do_simd, simdItemDSP);
   return wsloopOp;
 }
 
diff --git a/flang/test/Lower/OpenMP/wsloop-simd.f90 b/flang/test/Lower/OpenMP/wsloop-simd.f90
index 49a9a523e11fe..d26e93d9a5113 100644
--- a/flang/test/Lower/OpenMP/wsloop-simd.f90
+++ b/flang/test/Lower/OpenMP/wsloop-simd.f90
@@ -7,7 +7,7 @@
 subroutine do_simd_aligned(A)
   use iso_c_binding
   type(c_ptr) :: A
-  
+
   ! CHECK:      omp.wsloop
   ! CHECK-NOT:  aligned({{.*}})
   ! CHECK-SAME: {
@@ -66,3 +66,22 @@ subroutine do_simd_reduction()
     end do
   !$omp end do simd
 end subroutine do_simd_reduction
+
+! CHECK-LABEL: func.func @_QPdo_simd_private(
+subroutine do_simd_private()
+  integer, allocatable :: tmp
+  ! CHECK:      omp.wsloop
+  ! CHECK-NEXT: omp.simd
+  ! CHECK-SAME: private(@[[PRIV_BOX_SYM:.*]] %{{.*}} -> %[[PRIV_BOX:.*]], @[[PRIV_IVAR_SYM:.*]] %{{.*}} -> %[[PRIV_IVAR:.*]] : !fir.ref<!fir.box<!fir.heap<i32>>>, !fir.ref<i32>)
+  ! CHECK-NEXT: omp.loop_nest (%[[IVAR:.*]]) : i32
+  !$omp do simd private(tmp)
+  do i=1, 10
+  ! CHECK:      %[[PRIV_BOX_DECL:.*]]:2 = hlfir.declare %[[PRIV_BOX]]
+  ! CHECK:      %[[PRIV_IVAR_DECL:.*]]:2 = hlfir.declare %[[PRIV_IVAR]]
+  ! CHECK:      hlfir.assign %[[IVAR]] to %[[PRIV_IVAR_DECL]]#0
+  ! CHECK:      %[[PRIV_BOX_LOAD:.*]] = fir.load %[[PRIV_BOX_DECL]]
+  ! CHECK:      hlfir.assign %{{.*}} to %[[PRIV_BOX_DECL]]#0
+  ! CHECK:      omp.yield
+    tmp = tmp + 1
+  end do
+end subroutine do_simd_private