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abidhabidh
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[OMPIRBuilder][debug] Fix debug info for variables in target region.
When a new function is created to handle OpenMP target region, the variables used in it are passed as arguments. The scope and the location of these variable contains still point to te parent function of the target region. Such variables will fail in Verifier as the scope of the variables will be different from the containing functions. Currently, flang is the only user of createOutlinedFunction and it does not generate any debug data for the the variables in the target region to avoid this error. When this PR is in, we should be able to remove this limit in the flang (and anyother client) and have the better debug experience for the target region. This PR changes the location and scope of the variables in the target region to point to correct entities. It is similar to what fixupDebugInfoPostExtraction does for CodeExtractor. I initially tried to re-use that function but found quickly that it would require quite a bit of re-factoring and additions before it could be used. It was much simpler to make the changes locally.
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‎llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp‎

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Original file line numberDiff line numberDiff line change
@@ -38,6 +38,8 @@
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#include "llvm/IR/Function.h"
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#include "llvm/IR/GlobalVariable.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/InstIterator.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/MDBuilder.h"
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#include "llvm/IR/Metadata.h"
@@ -6929,6 +6931,8 @@ static Expected<Function *> createOutlinedFunction(
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? make_range(Func->arg_begin() + 1, Func->arg_end())
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: Func->args();
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DenseMap<Value *, std::tuple<Value *, unsigned>> ValueReplacementMap;
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auto ReplaceValue = [](Value *Input, Value *InputCopy, Function *Func) {
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// Things like GEP's can come in the form of Constants. Constants and
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// ConstantExpr's do not have access to the knowledge of what they're
@@ -6970,6 +6974,7 @@ static Expected<Function *> createOutlinedFunction(
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if (!AfterIP)
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return AfterIP.takeError();
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Builder.restoreIP(*AfterIP);
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ValueReplacementMap[Input] = std::make_tuple(InputCopy, Arg.getArgNo());
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// In certain cases a Global may be set up for replacement, however, this
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// Global may be used in multiple arguments to the kernel, just segmented
@@ -7001,6 +7006,67 @@ static Expected<Function *> createOutlinedFunction(
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for (auto Deferred : DeferredReplacement)
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ReplaceValue(std::get<0>(Deferred), std::get<1>(Deferred), Func);
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DenseMap<const MDNode *, MDNode *> Cache;
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SmallDenseMap<DILocalVariable *, DILocalVariable *> RemappedVariables;
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auto GetUpdatedDIVariable = [&](DILocalVariable *OldVar, unsigned arg) {
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auto NewSP = Func->getSubprogram();
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DILocalVariable *&NewVar = RemappedVariables[OldVar];
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if (!NewVar) {
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DILocalScope *NewScope = DILocalScope::cloneScopeForSubprogram(
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*OldVar->getScope(), *NewSP, Builder.getContext(), Cache);
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NewVar = llvm::DILocalVariable::get(
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Builder.getContext(), NewScope, OldVar->getName(), OldVar->getFile(),
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OldVar->getLine(), OldVar->getType(), arg, OldVar->getFlags(),
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OldVar->getAlignInBits(), OldVar->getAnnotations());
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}
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return NewVar;
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};
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DISubprogram *NewSP = Func->getSubprogram();
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if (NewSP) {
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// The location and scope of variable intrinsics and records still point to
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// the parent function of the target region. Update them.
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for (Instruction &I : instructions(Func)) {
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if (auto *DDI = dyn_cast<llvm::DbgVariableIntrinsic>(&I)) {
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DILocalVariable *OldVar = DDI->getVariable();
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unsigned ArgNo = OldVar->getArg();
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for (auto Loc : DDI->location_ops()) {
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auto Iter = ValueReplacementMap.find(Loc);
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if (Iter != ValueReplacementMap.end()) {
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DDI->replaceVariableLocationOp(Loc, std::get<0>(Iter->second));
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ArgNo = std::get<1>(Iter->second) + 1;
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}
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}
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DDI->setVariable(GetUpdatedDIVariable(OldVar, ArgNo));
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}
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for (DbgVariableRecord &DVR : filterDbgVars(I.getDbgRecordRange())) {
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DILocalVariable *OldVar = DVR.getVariable();
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unsigned ArgNo = OldVar->getArg();
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for (auto Loc : DVR.location_ops()) {
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auto Iter = ValueReplacementMap.find(Loc);
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if (Iter != ValueReplacementMap.end()) {
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DVR.replaceVariableLocationOp(Loc, std::get<0>(Iter->second));
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ArgNo = std::get<1>(Iter->second) + 1;
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}
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}
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DVR.setVariable(GetUpdatedDIVariable(OldVar, ArgNo));
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}
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}
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// An extra argument is passed to the device. Create the debug data for it.
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if (OMPBuilder.Config.isTargetDevice()) {
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DICompileUnit *CU = NewSP->getUnit();
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DIBuilder DB(*M, true, CU);
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DIType *VoidPtrTy =
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DB.createQualifiedType(dwarf::DW_TAG_pointer_type, nullptr);
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DILocalVariable *Var = DB.createParameterVariable(
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NewSP, "dyn_ptr", /*ArgNo*/ 1, NewSP->getFile(), /*LineNo=*/0,
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VoidPtrTy, /*AlwaysPreserve=*/false, DINode::DIFlags::FlagArtificial);
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auto Loc = DILocation::get(Func->getContext(), 0, 0, NewSP, 0);
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DB.insertDeclare(&(*Func->arg_begin()), Var, DB.createExpression(), Loc,
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&(*Func->begin()));
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}
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}
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return Func;
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}
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‎mlir/test/Target/LLVMIR/omptarget-debug-var-1.mlir‎

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@@ -0,0 +1,63 @@
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// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
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#int_ty = #llvm.di_basic_type<tag = DW_TAG_base_type, name = "integer",
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sizeInBits = 32, encoding = DW_ATE_signed>
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#real_ty = #llvm.di_basic_type<tag = DW_TAG_base_type, name = "real",
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sizeInBits = 32, encoding = DW_ATE_float>
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#file = #llvm.di_file<"target.f90" in "">
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#di_null_type = #llvm.di_null_type
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#cu = #llvm.di_compile_unit<id = distinct[0]<>,
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sourceLanguage = DW_LANG_Fortran95, file = #file, isOptimized = false,
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emissionKind = Full>
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#array_ty = #llvm.di_composite_type<tag = DW_TAG_array_type,
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baseType = #int_ty, elements = #llvm.di_subrange<count = 10 : i64>>
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#sp_ty = #llvm.di_subroutine_type<callingConvention = DW_CC_program,
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types = #di_null_type>
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#g_var = #llvm.di_global_variable<scope = #cu, name = "arr",
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linkageName = "_QFEarr", file = #file, line = 4,
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type = #array_ty, isDefined = true>
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#g_var_expr = #llvm.di_global_variable_expression<var = #g_var>
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#sp = #llvm.di_subprogram<id = distinct[2]<>, compileUnit = #cu, scope = #file,
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name = "test", file = #file, subprogramFlags = "Definition", type = #sp_ty>
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#var_arr = #llvm.di_local_variable<scope = #sp,
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name = "arr", file = #file, line = 4, type = #array_ty>
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#var_i = #llvm.di_local_variable<scope = #sp,
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name = "i", file = #file, line = 13, type = #int_ty>
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#var_x = #llvm.di_local_variable<scope = #sp,
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name = "x", file = #file, line = 12, type = #real_ty>
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module attributes {omp.is_target_device = true} {
30+
llvm.func @test() {
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%0 = llvm.mlir.constant(1 : i64) : i64
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%1 = llvm.alloca %0 x f32 : (i64) -> !llvm.ptr
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%4 = llvm.alloca %0 x i32 : (i64) -> !llvm.ptr
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%6 = llvm.mlir.constant(9 : index) : i64
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%7 = llvm.mlir.constant(0 : index) : i64
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%8 = llvm.mlir.constant(1 : index) : i64
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%10 = llvm.mlir.constant(10 : index) : i64
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%11 = llvm.mlir.addressof @_QFEarr : !llvm.ptr
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%14 = omp.map.info var_ptr(%1 : !llvm.ptr, f32) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr
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%15 = omp.map.bounds lower_bound(%7 : i64) upper_bound(%6 : i64) extent(%10 : i64) stride(%8 : i64) start_idx(%8 : i64)
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%16 = omp.map.info var_ptr(%11 : !llvm.ptr, !llvm.array<10 x i32>) map_clauses(tofrom) capture(ByRef) bounds(%15) -> !llvm.ptr
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%17 = omp.map.info var_ptr(%4 : !llvm.ptr, i32) map_clauses(implicit, exit_release_or_enter_alloc) capture(ByCopy) -> !llvm.ptr
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omp.target map_entries(%14 -> %arg0, %16 -> %arg1, %17 -> %arg2 : !llvm.ptr, !llvm.ptr, !llvm.ptr) {
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llvm.intr.dbg.declare #var_x = %arg0 : !llvm.ptr
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llvm.intr.dbg.declare #var_arr = %arg1 : !llvm.ptr
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llvm.intr.dbg.declare #var_i = %arg2 : !llvm.ptr
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omp.terminator
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}
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llvm.return
50+
} loc(#loc3)
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llvm.mlir.global internal @_QFEarr() {addr_space = 0 : i32, dbg_exprs = [#g_var_expr]} : !llvm.array<10 x i32> {
52+
} loc(#loc4)
53+
}
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#loc1 = loc("target.f90":4:7)
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#loc2 = loc("target.f90":11:7)
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#loc3 = loc(fused<#sp>[#loc2])
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#loc4 = loc(fused<#g_var>[#loc1])
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// CHECK: ![[SP:[0-9]+]] = distinct !DISubprogram(name: "__omp_offloading{{.*}}test{{.*}})
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// CHECK: !DILocalVariable(name: "dyn_ptr", arg: 1, scope: ![[SP]]{{.*}}flags: DIFlagArtificial)
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// CHECK: !DILocalVariable(name: "x", arg: 2, scope: ![[SP]]{{.*}})
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// CHECK: !DILocalVariable(name: "arr", arg: 3, scope: ![[SP]]{{.*}})
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// CHECK: !DILocalVariable(name: "i", arg: 4, scope: ![[SP]]{{.*}})

‎mlir/test/Target/LLVMIR/omptarget-debug-var-2.mlir‎

Lines changed: 62 additions & 0 deletions
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@@ -0,0 +1,62 @@
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// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
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#int_ty = #llvm.di_basic_type<tag = DW_TAG_base_type, name = "integer",
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sizeInBits = 32, encoding = DW_ATE_signed>
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#real_ty = #llvm.di_basic_type<tag = DW_TAG_base_type, name = "real",
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sizeInBits = 32, encoding = DW_ATE_float>
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#file = #llvm.di_file<"target.f90" in "">
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#di_null_type = #llvm.di_null_type
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#cu = #llvm.di_compile_unit<id = distinct[0]<>,
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sourceLanguage = DW_LANG_Fortran95, file = #file, isOptimized = false,
11+
emissionKind = Full>
12+
#array_ty = #llvm.di_composite_type<tag = DW_TAG_array_type,
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baseType = #int_ty, elements = #llvm.di_subrange<count = 10 : i64>>
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#sp_ty = #llvm.di_subroutine_type<callingConvention = DW_CC_program,
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types = #di_null_type>
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#g_var = #llvm.di_global_variable<scope = #cu, name = "arr",
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linkageName = "_QFEarr", file = #file, line = 4,
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type = #array_ty, isDefined = true>
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#g_var_expr = #llvm.di_global_variable_expression<var = #g_var>
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#sp = #llvm.di_subprogram<id = distinct[2]<>, compileUnit = #cu, scope = #file,
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name = "test", file = #file, subprogramFlags = "Definition", type = #sp_ty>
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#var_arr = #llvm.di_local_variable<scope = #sp,
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name = "arr", file = #file, line = 4, type = #array_ty>
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#var_i = #llvm.di_local_variable<scope = #sp,
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name = "i", file = #file, line = 13, type = #int_ty>
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#var_x = #llvm.di_local_variable<scope = #sp,
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name = "x", file = #file, line = 12, type = #real_ty>
28+
29+
module attributes {omp.is_target_device = false} {
30+
llvm.func @test() {
31+
%0 = llvm.mlir.constant(1 : i64) : i64
32+
%1 = llvm.alloca %0 x f32 : (i64) -> !llvm.ptr
33+
%4 = llvm.alloca %0 x i32 : (i64) -> !llvm.ptr
34+
%6 = llvm.mlir.constant(9 : index) : i64
35+
%7 = llvm.mlir.constant(0 : index) : i64
36+
%8 = llvm.mlir.constant(1 : index) : i64
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%10 = llvm.mlir.constant(10 : index) : i64
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%11 = llvm.mlir.addressof @_QFEarr : !llvm.ptr
39+
%14 = omp.map.info var_ptr(%1 : !llvm.ptr, f32) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr
40+
%15 = omp.map.bounds lower_bound(%7 : i64) upper_bound(%6 : i64) extent(%10 : i64) stride(%8 : i64) start_idx(%8 : i64)
41+
%16 = omp.map.info var_ptr(%11 : !llvm.ptr, !llvm.array<10 x i32>) map_clauses(tofrom) capture(ByRef) bounds(%15) -> !llvm.ptr
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%17 = omp.map.info var_ptr(%4 : !llvm.ptr, i32) map_clauses(implicit, exit_release_or_enter_alloc) capture(ByCopy) -> !llvm.ptr
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omp.target map_entries(%14 -> %arg0, %16 -> %arg1, %17 -> %arg2 : !llvm.ptr, !llvm.ptr, !llvm.ptr) {
44+
llvm.intr.dbg.declare #var_x = %arg0 : !llvm.ptr
45+
llvm.intr.dbg.declare #var_arr = %arg1 : !llvm.ptr
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llvm.intr.dbg.declare #var_i = %arg2 : !llvm.ptr
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omp.terminator
48+
}
49+
llvm.return
50+
} loc(#loc3)
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llvm.mlir.global internal @_QFEarr() {addr_space = 0 : i32, dbg_exprs = [#g_var_expr]} : !llvm.array<10 x i32> {
52+
} loc(#loc4)
53+
}
54+
#loc1 = loc("target.f90":4:7)
55+
#loc2 = loc("target.f90":11:7)
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#loc3 = loc(fused<#sp>[#loc2])
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#loc4 = loc(fused<#g_var>[#loc1])
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59+
// CHECK: ![[SP:[0-9]+]] = distinct !DISubprogram(name: "__omp_offloading{{.*}}test{{.*}})
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// CHECK: !DILocalVariable(name: "x", arg: 1, scope: ![[SP]]{{.*}})
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// CHECK: !DILocalVariable(name: "arr", arg: 2, scope: ![[SP]]{{.*}})
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// CHECK: !DILocalVariable(name: "i", arg: 3, scope: ![[SP]]{{.*}})

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