[OpenMP][IR] Set correct alignment for internal variables

OpenMP runtime functions assume the pointers are aligned to sizeof(pointer),
but it is being aligned incorrectly. Fix with the proper alignment in the IR builder.

Reviewed By: tianshilei1992

Differential Revision: https://reviews.llvm.org/D157040

clang/lib/CodeGen/CGOpenMPRuntime.cpp

@@ -2161,11 +2161,7 @@ Address CGOpenMPRuntime::emitThreadIDAddress(CodeGenFunction &CGF,
 llvm::Value *CGOpenMPRuntime::getCriticalRegionLock(StringRef CriticalName) {
   std::string Prefix = Twine("gomp_critical_user_", CriticalName).str();
   std::string Name = getName({Prefix, "var"});
-  llvm::GlobalVariable *G = OMPBuilder.getOrCreateInternalVariable(KmpCriticalNameTy, Name);
-  llvm::Align PtrAlign = OMPBuilder.M.getDataLayout().getPointerABIAlignment(G->getAddressSpace());
-  if (PtrAlign > llvm::Align(G->getAlignment()))
-    G->setAlignment(PtrAlign);
-  return G;
+  return OMPBuilder.getOrCreateInternalVariable(KmpCriticalNameTy, Name);
 }
 
 namespace {

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

@@ -4493,7 +4493,10 @@ OpenMPIRBuilder::getOrCreateInternalVariable(Type *Ty, const StringRef &Name,
         M, Ty, /*IsConstant=*/false, GlobalValue::CommonLinkage,
         Constant::getNullValue(Ty), Elem.first(),
         /*InsertBefore=*/nullptr, GlobalValue::NotThreadLocal, AddressSpace);
-    GV->setAlignment(M.getDataLayout().getABITypeAlign(Ty));
+    const DataLayout &DL = M.getDataLayout();
+    const llvm::Align TypeAlign = DL.getABITypeAlign(Ty);
+    const llvm::Align PtrAlign = DL.getPointerABIAlignment(AddressSpace);
+    GV->setAlignment(std::max(TypeAlign, PtrAlign));
     Elem.second = GV;
   }
 

llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp

@@ -2744,7 +2744,15 @@ TEST_F(OpenMPIRBuilderTest, CriticalDirective) {
   PointerType *CriticalNamePtrTy =
       PointerType::getUnqual(ArrayType::get(Type::getInt32Ty(Ctx), 8));
   EXPECT_EQ(CriticalEndCI->getArgOperand(2), CriticalEntryCI->getArgOperand(2));
-  EXPECT_EQ(CriticalEndCI->getArgOperand(2)->getType(), CriticalNamePtrTy);
+  GlobalVariable *GV =
+      dyn_cast<GlobalVariable>(CriticalEndCI->getArgOperand(2));
+  ASSERT_NE(GV, nullptr);
+  EXPECT_EQ(GV->getType(), CriticalNamePtrTy);
+  const DataLayout &DL = M->getDataLayout();
+  const llvm::Align TypeAlign = DL.getABITypeAlign(CriticalNamePtrTy);
+  const llvm::Align PtrAlign = DL.getPointerABIAlignment(GV->getAddressSpace());
+  if (const llvm::MaybeAlign Alignment = GV->getAlign())
+    EXPECT_EQ(*Alignment, std::max(TypeAlign, PtrAlign));
 }
 
 TEST_F(OpenMPIRBuilderTest, OrderedDirectiveDependSource) {