[flang] Fix OMPEarlyOutlining erasing declare target functions

The early outlining pass was erasing target functions that need to be kept. It should only erase functions that contain target ops.
llvm · Jul 13, 2023 · 22a1677 · 22a1677
1 parent ca8ef82
commit 22a1677
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Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/flang/lib/Optimizer/Transforms/OMPEarlyOutlining.cpp b/flang/lib/Optimizer/Transforms/OMPEarlyOutlining.cpp
@@ -82,7 +82,8 @@ class OMPEarlyOutliningPass
     return newFunc;
   }
 
-  void outlineTargetOps(mlir::OpBuilder &builder,
+  // Returns true if a target region was found int the function.
+  bool outlineTargetOps(mlir::OpBuilder &builder,
                         mlir::func::FuncOp &functionOp,
                         mlir::ModuleOp &moduleOp,
                         llvm::SmallVectorImpl<mlir::func::FuncOp> &newFuncs) {
@@ -93,6 +94,7 @@ class OMPEarlyOutliningPass
       newFuncs.push_back(outlinedFunc);
       count++;
     }
+    return count > 0;
   }
 
   void runOnOperation() override {
@@ -103,8 +105,9 @@ class OMPEarlyOutliningPass
 
     for (auto functionOp :
          llvm::make_early_inc_range(moduleOp.getOps<mlir::func::FuncOp>())) {
-      outlineTargetOps(builder, functionOp, moduleOp, newFuncs);
-      functionOp.erase();
+      bool outlined = outlineTargetOps(builder, functionOp, moduleOp, newFuncs);
+      if (outlined)
+        functionOp.erase();
     }
 
     for (auto newFunc : newFuncs)

diff --git a/flang/test/Lower/OpenMP/omp-target-early-outlining.f90 b/flang/test/Lower/OpenMP/omp-target-early-outlining.f90
@@ -3,6 +3,8 @@
 !RUN: %flang_fc1 -triple amdgcn-amd-amdhsa -emit-fir -fopenmp -fopenmp-is-device %s -o - | FileCheck %s
 !RUN: %flang_fc1 -triple x86_64-unknown-linux-gnu -emit-fir -fopenmp -fopenmp-is-device %s -o - | FileCheck %s
 
+!CHECK: func.func @_QPtarget_function
+
 !CHECK:  func.func @_QPwrite_index_omp_outline_0(%[[ARG0:.*]]: !fir.ref<i32>) attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (to)>, omp.outline_parent_name = "_QPwrite_index"} {
 !CHECK-NEXT: omp.target  {{.*}} {
 !CHECK: %[[CONSTANT_VALUE_10:.*]] = arith.constant 10 : i32
@@ -33,3 +35,7 @@ SUBROUTINE WRITE_INDEX(INT_ARRAY)
                 INT_ARRAY(INDEX_) = INDEX_
         end do
 end subroutine WRITE_INDEX
+
+SUBROUTINE TARGET_FUNCTION()
+!$omp declare target
+END