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-rw-r--r--clang/lib/CodeGen/ItaniumCXXABI.cpp11
-rw-r--r--clang/test/CodeGenCXX/virtual-function-calls.cpp7
2 files changed, 16 insertions, 2 deletions
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 8392f6a7ba2..37b49dc6086 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -1609,7 +1609,16 @@ llvm::Value *ItaniumCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
uint64_t VTableIndex = CGM.getItaniumVTableContext().getMethodVTableIndex(GD);
llvm::Value *VFuncPtr =
CGF.Builder.CreateConstInBoundsGEP1_64(VTable, VTableIndex, "vfn");
- return CGF.Builder.CreateAlignedLoad(VFuncPtr, CGF.getPointerAlign());
+ auto *Inst = CGF.Builder.CreateAlignedLoad(VFuncPtr, CGF.getPointerAlign());
+
+ // It's safe to add "invariant.load" without -fstrict-vtable-pointers, but it
+ // would not help in devirtualization.
+ if (CGM.getCodeGenOpts().OptimizationLevel > 0 &&
+ CGM.getCodeGenOpts().StrictVTablePointers)
+ Inst->setMetadata(llvm::LLVMContext::MD_invariant_load,
+ llvm::MDNode::get(CGM.getLLVMContext(),
+ llvm::ArrayRef<llvm::Metadata *>()));
+ return Inst;
}
llvm::Value *ItaniumCXXABI::EmitVirtualDestructorCall(
diff --git a/clang/test/CodeGenCXX/virtual-function-calls.cpp b/clang/test/CodeGenCXX/virtual-function-calls.cpp
index 0a6fc6b3f28..09dfbb1c631 100644
--- a/clang/test/CodeGenCXX/virtual-function-calls.cpp
+++ b/clang/test/CodeGenCXX/virtual-function-calls.cpp
@@ -1,4 +1,5 @@
// RUN: %clang_cc1 %s -triple %itanium_abi_triple -std=c++11 -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple %itanium_abi_triple -std=c++11 -emit-llvm -o - -fstrict-vtable-pointers -O1 | FileCheck --check-prefix=CHECK-INVARIANT %s
// PR5021
namespace PR5021 {
@@ -42,10 +43,14 @@ namespace VirtualNoreturn {
[[noreturn]] virtual void f();
};
- // CHECK: @_ZN15VirtualNoreturn1f
+ // CHECK-LABEL: @_ZN15VirtualNoreturn1f
+ // CHECK-INVARIANT-LABEL: define void @_ZN15VirtualNoreturn1f
void f(A *p) {
p->f();
// CHECK: call {{.*}}void %{{[^#]*$}}
// CHECK-NOT: unreachable
+ // CHECK-INVARIANT: load {{.*}} align 8, !invariant.load ![[EMPTY_NODE:[0-9]]]
}
}
+
+// CHECK-INVARIANT: ![[EMPTY_NODE]] = !{}
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