[OPENMP]Fix for PR43349: Crash for privatized loop bound.

If the variable, used in the loop boundaries, is not captured in the
construct, this variable must be considered as undefined if it was
privatized.

llvm-svn: 372252

2 files changed, 20 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index 473c6f7950a..e34b820625c 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -120,11 +120,27 @@ public:
 class OMPLoopScope : public CodeGenFunction::RunCleanupsScope {
   void emitPreInitStmt(CodeGenFunction &CGF, const OMPLoopDirective &S) {
     CodeGenFunction::OMPMapVars PreCondVars;
+    llvm::DenseSet<const VarDecl *> EmittedAsPrivate;
     for (const auto *E : S.counters()) {
       const auto *VD = cast<VarDecl>(cast<DeclRefExpr>(E)->getDecl());
+      EmittedAsPrivate.insert(VD->getCanonicalDecl());
       (void)PreCondVars.setVarAddr(
           CGF, VD, CGF.CreateMemTemp(VD->getType().getNonReferenceType()));
     }
+    // Mark private vars as undefs.
+    for (const auto *C : S.getClausesOfKind<OMPPrivateClause>()) {
+      for (const Expr *IRef : C->varlists()) {
+        const auto *OrigVD = cast<VarDecl>(cast<DeclRefExpr>(IRef)->getDecl());
+        if (EmittedAsPrivate.insert(OrigVD->getCanonicalDecl()).second) {
+          (void)PreCondVars.setVarAddr(
+              CGF, OrigVD,
+              Address(llvm::UndefValue::get(
+                          CGF.ConvertTypeForMem(CGF.getContext().getPointerType(
+                              OrigVD->getType().getNonReferenceType()))),
+                      CGF.getContext().getDeclAlign(OrigVD)));
+        }
+      }
+    }
     (void)PreCondVars.apply(CGF);
     if (const auto *PreInits = cast_or_null<DeclStmt>(S.getPreInits())) {
       for (const auto *I : PreInits->decls())
diff --git a/clang/test/OpenMP/parallel_for_codegen.cpp b/clang/test/OpenMP/parallel_for_codegen.cpp
index 4329dd4f939..9e3390214d7 100644
--- a/clang/test/OpenMP/parallel_for_codegen.cpp
+++ b/clang/test/OpenMP/parallel_for_codegen.cpp
@@ -35,12 +35,14 @@ void with_var_schedule() {
 // CHECK: [[CHUNK:%.+]] = load i64, i64* %
 // CHECK: call void {{.+}} @__kmpc_fork_call({{.+}}, i64 [[CHUNK]])
 
+// CHECK: [[UNDEF_A:%.+]] = load double, double* undef
+// CHECK: fadd double 2.000000e+00, [[UNDEF_A]]
 // CHECK: [[CHUNK_VAL:%.+]] = load i8, i8* %
 // CHECK: [[CHUNK_SIZE:%.+]] = sext i8 [[CHUNK_VAL]] to i64
 // CHECK: call void @__kmpc_for_static_init_8u([[IDENT_T_TY]]* [[LOOP_LOC]], i32 [[GTID:%[^,]+]], i32 33, i32* [[IS_LAST:%[^,]+]], i64* [[OMP_LB:%[^,]+]], i64* [[OMP_UB:%[^,]+]], i64* [[OMP_ST:%[^,]+]], i64 1, i64 [[CHUNK_SIZE]])
 // CHECK: call void @__kmpc_for_static_fini([[IDENT_T_TY]]* [[LOOP_LOC]], i32 [[GTID]])
-#pragma omp parallel for schedule(static, char(a))
-  for (unsigned long long i = 1; i < 2; ++i) {
+#pragma omp parallel for schedule(static, char(a)) private(a)
+  for (unsigned long long i = 1; i < 2 + a; ++i) {
   }
 }