side effect of intrinsics

definition ： http://llvm-cs.pcc.me.uk/include/llvm/IR/Intrinsics.td

class IntrinsicProperty;

// Intr*Mem - Memory properties. If no property is set, the worst case is assumed (it may read and write any memory it can get access to and it may have other side effects).

// IntrNoMem - The intrinsic does not access memory or have any other side effects. It may be CSE’d deleted if dead, etc.
def IntrNoMem : IntrinsicProperty;

// IntrReadMem - This intrinsic only reads from memory. It does not write to memory and has no other side effects. Therefore, it cannot be moved across potentially aliasing stores. However, it can be reordered otherwise and can be deleted if dead.
def IntrReadMem : IntrinsicProperty;

// IntrWriteMem - This intrinsic only writes to memory, but does not read from memory, and has no other side effects. This means dead stores before calls to this intrinsics may be removed.
def IntrWriteMem : IntrinsicProperty;

// IntrArgMemOnly - This intrinsic only accesses memory that its pointer-typed argument(s) points to, but may access an unspecified amount. Other than reads from and (possibly volatile) writes to memory, it has no side effects.
def IntrArgMemOnly : IntrinsicProperty;

// NoAlias - The specified argument pointer is not aliasing other “noalias” pointer arguments of the intrinsic wrt. the intrinsic scope.
class NoAlias : IntrinsicProperty {
int ArgNo = argNo;
}

// Returned - The specified argument is always the return value of the intrinsic.
class Returned : IntrinsicProperty {
int ArgNo = argNo;
}

def IntrNoReturn : IntrinsicProperty;

def int_vclr_vacc : Intrinsic<[llvm_v8192i1_ty], [],  [IntrNoMem], "llvm.vclr.vacc">;

def int_mbarrier : Intrinsic<[], [], [IntrHasSideEffects], "llvm.mbarrier">;

// vector load/store
def int_vld : Intrinsic<[llvm_v1024i1_ty], [llvm_anyptr_ty],  [IntrReadMem, IntrArgMemOnly], "llvm.vld">;

def int_vstl : Intrinsic<[], [llvm_v1024i1_ty, llvm_anyptr_ty, llvm_i32_ty], [IntrWriteMem, IntrArgMemOnly], "llvm.vstl">;