Emit memmove, not memcpy, for structure copies; this is unfortunately
required for correctness in cases of copying a struct to itself or to
an overlapping struct (itself for cases like *a = *a, and overlapping
is possible with unions).
Hopefully, this won't end up being a perf issue; LLVM *should* be able
to optimize memmove to memcpy in a lot of cases, and for small copies
the generated code *should* be mostly comparable. (In reality, LLVM
is currently horrible at optimizing memmove, but that's a bug, not a
fundamental issue.)
gcc currently generates wrong code; that's
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32667.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@51566 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index bc216e4..992a3bf 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -59,6 +59,7 @@
CGDebugInfo *DebugInfo;
llvm::Function *MemCpyFn;
+ llvm::Function *MemMoveFn;
llvm::Function *MemSetFn;
llvm::DenseMap<const Decl*, llvm::Constant*> GlobalDeclMap;
std::vector<const NamedDecl*> StaticDecls;
@@ -101,6 +102,7 @@
/// array containing the literal. The result is pointer to array type.
llvm::Constant *GetAddrOfConstantString(const std::string& str);
llvm::Function *getMemCpyFn();
+ llvm::Function *getMemMoveFn();
llvm::Function *getMemSetFn();
llvm::Function *getIntrinsic(unsigned IID, const llvm::Type **Tys = 0,
unsigned NumTys = 0);