On Wed, Sep 30, 2015 at 8:52 PM Piotr Padlewski via cfe-commits < cfe-commits@lists.llvm.org> wrote:
> Author: prazek > Date: Wed Sep 30 22:50:41 2015 > New Revision: 248982 > > URL: http://llvm.org/viewvc/llvm-project?rev=248982&view=rev > Log: > Decorating virtual functions load with invariant.load > This change description really doesn't tell me anything about what this change does. Could you try to write more detailed and explanatory change logs? Imagine a reader that has little or no context reading the change log to gain the context necessary to read the actual patch and understand what is going on with it. > > http://reviews.llvm.org/D13279 > > Modified: > cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp > cfe/trunk/test/CodeGenCXX/virtual-function-calls.cpp > > Modified: cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp?rev=248982&r1=248981&r2=248982&view=diff > > ============================================================================== > --- cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp (original) > +++ cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp Wed Sep 30 22:50:41 2015 > @@ -1609,7 +1609,16 @@ llvm::Value *ItaniumCXXABI::getVirtualFu > 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( > > Modified: cfe/trunk/test/CodeGenCXX/virtual-function-calls.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/virtual-function-calls.cpp?rev=248982&r1=248981&r2=248982&view=diff > > ============================================================================== > --- cfe/trunk/test/CodeGenCXX/virtual-function-calls.cpp (original) > +++ cfe/trunk/test/CodeGenCXX/virtual-function-calls.cpp Wed Sep 30 > 22:50:41 2015 > @@ -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]] = !{} > > > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >
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