Teach AliasAnalysis that a bunch of the atomic intrinsics only dereference their arguments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63616 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp
index d5de2fe..2571492 100644
--- a/lib/Analysis/AliasAnalysis.cpp
+++ b/lib/Analysis/AliasAnalysis.cpp
@@ -28,6 +28,7 @@
#include "llvm/Pass.h"
#include "llvm/BasicBlock.h"
#include "llvm/Function.h"
+#include "llvm/IntrinsicInst.h"
#include "llvm/Instructions.h"
#include "llvm/Type.h"
#include "llvm/Target/TargetData.h"
@@ -114,6 +115,27 @@
AliasAnalysis::ModRefBehavior
AliasAnalysis::getModRefBehavior(CallSite CS,
std::vector<PointerAccessInfo> *Info) {
+ if (IntrinsicInst* II = dyn_cast<IntrinsicInst>(CS.getInstruction())) {
+ switch (II->getIntrinsicID()) {
+ case Intrinsic::atomic_cmp_swap:
+ case Intrinsic::atomic_load_add:
+ case Intrinsic::atomic_load_and:
+ case Intrinsic::atomic_load_max:
+ case Intrinsic::atomic_load_min:
+ case Intrinsic::atomic_load_nand:
+ case Intrinsic::atomic_load_or:
+ case Intrinsic::atomic_load_sub:
+ case Intrinsic::atomic_load_umax:
+ case Intrinsic::atomic_load_umin:
+ case Intrinsic::atomic_load_xor:
+ case Intrinsic::atomic_swap:
+ // CAS and related intrinsics only access their arguments.
+ return AliasAnalysis::AccessesArguments;
+ default:
+ break;
+ }
+ }
+
if (CS.doesNotAccessMemory())
// Can't do better than this.
return DoesNotAccessMemory;