r237243 - [OPENMP] Fixed codegen for firstprivate variables, also marked as lastprivate.

[Alexey Bataev]

Author: abataev
Date: Wed May 13 05:23:02 2015
New Revision: 237243

URL: http://llvm.org/viewvc/llvm-project?rev=237243&view=rev
Log:
[OPENMP] Fixed codegen for firstprivate variables, also marked as lastprivate.

In some rare cases shared copies of lastprivate/firstprivate variables were not updated after the loop directive.

Modified:
    cfe/trunk/lib/CodeGen/CGStmtOpenMP.cpp
    cfe/trunk/test/OpenMP/for_lastprivate_codegen.cpp

Modified: cfe/trunk/lib/CodeGen/CGStmtOpenMP.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGStmtOpenMP.cpp?rev=237243&r1=237242&r2=237243&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGStmtOpenMP.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGStmtOpenMP.cpp Wed May 13 05:23:02 2015
@@ -267,6 +267,7 @@ bool CodeGenFunction::EmitOMPLastprivate
   bool HasAtLeastOneLastprivate = false;
   llvm::DenseSet<const VarDecl *> AlreadyEmittedVars;
   for (auto &&I = D.getClausesOfKind(OMPC_lastprivate); I; ++I) {
+    HasAtLeastOneLastprivate = true;
     auto *C = cast<OMPLastprivateClause>(*I);
     auto IRef = C->varlist_begin();
     auto IDestRef = C->destination_exprs().begin();
@@ -287,17 +288,18 @@ bool CodeGenFunction::EmitOMPLastprivate
         // Check if the variable is also a firstprivate: in this case IInit is
         // not generated. Initialization of this variable will happen in codegen
         // for 'firstprivate' clause.
-        if (!IInit)
-          continue;
-        auto *VD = cast<VarDecl>(cast<DeclRefExpr>(IInit)->getDecl());
-        bool IsRegistered =
-            PrivateScope.addPrivate(OrigVD, [&]() -> llvm::Value *{
-              // Emit private VarDecl with copy init.
-              EmitDecl(*VD);
-              return GetAddrOfLocalVar(VD);
-            });
-        assert(IsRegistered && "lastprivate var already registered as private");
-        HasAtLeastOneLastprivate = HasAtLeastOneLastprivate || IsRegistered;
+        if (IInit) {
+          auto *VD = cast<VarDecl>(cast<DeclRefExpr>(IInit)->getDecl());
+          bool IsRegistered =
+              PrivateScope.addPrivate(OrigVD, [&]() -> llvm::Value *{
+                // Emit private VarDecl with copy init.
+                EmitDecl(*VD);
+                return GetAddrOfLocalVar(VD);
+              });
+          assert(IsRegistered &&
+                 "lastprivate var already registered as private");
+          (void)IsRegistered;
+        }
       }
       ++IRef, ++IDestRef;
     }

Modified: cfe/trunk/test/OpenMP/for_lastprivate_codegen.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/OpenMP/for_lastprivate_codegen.cpp?rev=237243&r1=237242&r2=237243&view=diff
==============================================================================
--- cfe/trunk/test/OpenMP/for_lastprivate_codegen.cpp (original)
+++ cfe/trunk/test/OpenMP/for_lastprivate_codegen.cpp Wed May 13 05:23:02 2015
@@ -173,6 +173,11 @@ int main() {
   for (int i = 0; i < 2; ++i) {
     A::x++;
   }
+#pragma omp parallel
+#pragma omp for firstprivate(f) lastprivate(f)
+  for (int i = 0; i < 2; ++i) {
+    A::x++;
+  }
   return tmain<int>();
 #endif
 }
@@ -183,6 +188,7 @@ int main() {
 // CHECK: %{{.+}} = bitcast [[CAP_MAIN_TY]]*
 // CHECK: call void (%{{.+}}*, i{{[0-9]+}}, void (i{{[0-9]+}}*, i{{[0-9]+}}*, ...)*, ...) @__kmpc_fork_call(%{{.+}}* @{{.+}}, i{{[0-9]+}} 1, void (i{{[0-9]+}}*, i{{[0-9]+}}*, ...)* bitcast (void (i{{[0-9]+}}*, i{{[0-9]+}}*, [[CAP_MAIN_TY]]*)* [[MAIN_MICROTASK:@.+]] to void
 // CHECK: call void (%{{.+}}*, i{{[0-9]+}}, void (i{{[0-9]+}}*, i{{[0-9]+}}*, ...)*, ...) @__kmpc_fork_call(%{{.+}}* @{{.+}}, i{{[0-9]+}} 1, void (i{{[0-9]+}}*, i{{[0-9]+}}*, ...)* bitcast (void (i{{[0-9]+}}*, i{{[0-9]+}}*, %{{.+}}*)* [[MAIN_MICROTASK1:@.+]] to void
+// CHECK: call void (%{{.+}}*, i{{[0-9]+}}, void (i{{[0-9]+}}*, i{{[0-9]+}}*, ...)*, ...) @__kmpc_fork_call(%{{.+}}* @{{.+}}, i{{[0-9]+}} 1, void (i{{[0-9]+}}*, i{{[0-9]+}}*, ...)* bitcast (void (i{{[0-9]+}}*, i{{[0-9]+}}*, %{{.+}}*)* [[MAIN_MICROTASK2:@.+]] to void
 // CHECK: = call {{.+}} [[TMAIN_INT:@.+]]()
 // CHECK: call void [[S_FLOAT_TY_DESTR:@.+]]([[S_FLOAT_TY]]*
 // CHECK: ret
@@ -288,6 +294,38 @@ int main() {
 
 // original f=private_f;
 // CHECK: [[F_VAL:%.+]] = load float, float* [[F_PRIV]],
+// CHECK: store float [[F_VAL]], float* [[F]],
+
+// CHECK-NEXT: br label %[[LAST_DONE]]
+// CHECK: [[LAST_DONE]]
+
+// CHECK: call i32 @__kmpc_cancel_barrier(%{{.+}}* [[IMPLICIT_BARRIER_LOC]], i{{[0-9]+}} [[GTID]])
+// CHECK: call i32 @__kmpc_cancel_barrier(%{{.+}}* [[IMPLICIT_BARRIER_LOC]], i{{[0-9]+}} [[GTID]])
+// CHECK: ret void
+
+// CHECK: define internal void [[MAIN_MICROTASK2]](i{{[0-9]+}}* [[GTID_ADDR:%.+]], i{{[0-9]+}}* %{{.+}}, %{{.+}}* %{{.+}})
+// CHECK: [[F_PRIV:%.+]] = alloca float,
+// CHECK-NOT: alloca float
+
+// Check for default initialization.
+// CHECK: [[F_VAL:%.+]] = load float, float* [[F]],
+// CHECK: store float [[F_VAL]], float* [[F_PRIV]],
+
+// CHECK: [[GTID_REF:%.+]] = load i{{[0-9]+}}*, i{{[0-9]+}}** [[GTID_ADDR_REF]]
+// CHECK: [[GTID:%.+]] = load i{{[0-9]+}}, i{{[0-9]+}}* [[GTID_REF]]
+// CHECK: call {{.+}} @__kmpc_for_static_init_4(%{{.+}}* @{{.+}}, i32 [[GTID]], i32 34, i32* [[IS_LAST_ADDR:%.+]], i32* %{{.+}}, i32* %{{.+}}, i32* %{{.+}}, i32 1, i32 1)
+// <Skip loop body>
+// CHECK: call void @__kmpc_for_static_fini(%{{.+}}* @{{.+}}, i32 [[GTID]])
+
+// Check for final copying of private values back to original vars.
+// CHECK: [[IS_LAST_VAL:%.+]] = load i32, i32* [[IS_LAST_ADDR]],
+// CHECK: [[IS_LAST_ITER:%.+]] = icmp ne i32 [[IS_LAST_VAL]], 0
+// CHECK: br i1 [[IS_LAST_ITER:%.+]], label %[[LAST_THEN:.+]], label %[[LAST_DONE:.+]]
+// CHECK: [[LAST_THEN]]
+// Actual copying.
+
+// original f=private_f;
+// CHECK: [[F_VAL:%.+]] = load float, float* [[F_PRIV]],
 // CHECK: store float [[F_VAL]], float* [[F]],
 
 // CHECK-NEXT: br label %[[LAST_DONE]]