1 files changed, 19 insertions, 34 deletions

diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index 0641342..bb5a23b 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -747,29 +747,31 @@ static bool isIntrinsicCall(const CallBase *Call, Intrinsic::ID IID) {
   return II && II->getIntrinsicID() == IID;
 }
 
-/// Returns the behavior when calling the given call site.
-FunctionModRefBehavior BasicAAResult::getModRefBehavior(const CallBase *Call) {
-  if (Call->doesNotAccessMemory())
-    // Can't do better than this.
+static FunctionModRefBehavior getModRefBehaviorFromAttrs(AttributeSet Attrs) {
+  if (Attrs.hasAttribute(Attribute::ReadNone))
     return FunctionModRefBehavior::none();
 
-  // If the callsite knows it only reads memory, don't return worse
-  // than that.
   ModRefInfo MR = ModRefInfo::ModRef;
-  if (Call->onlyReadsMemory())
+  if (Attrs.hasAttribute(Attribute::ReadOnly))
     MR = ModRefInfo::Ref;
-  else if (Call->onlyWritesMemory())
+  else if (Attrs.hasAttribute(Attribute::WriteOnly))
     MR = ModRefInfo::Mod;
 
-  FunctionModRefBehavior Min(MR);
-  if (Call->onlyAccessesArgMemory())
-    Min = FunctionModRefBehavior::argMemOnly(MR);
-  else if (Call->onlyAccessesInaccessibleMemory())
-    Min = FunctionModRefBehavior::inaccessibleMemOnly(MR);
-  else if (Call->onlyAccessesInaccessibleMemOrArgMem())
-    Min = FunctionModRefBehavior::inaccessibleOrArgMemOnly(MR);
+  if (Attrs.hasAttribute(Attribute::ArgMemOnly))
+    return FunctionModRefBehavior::argMemOnly(MR);
+  if (Attrs.hasAttribute(Attribute::InaccessibleMemOnly))
+    return FunctionModRefBehavior::inaccessibleMemOnly(MR);
+  if (Attrs.hasAttribute(Attribute::InaccessibleMemOrArgMemOnly))
+    return FunctionModRefBehavior::inaccessibleOrArgMemOnly(MR);
+  return FunctionModRefBehavior(MR);
+}
+
+/// Returns the behavior when calling the given call site.
+FunctionModRefBehavior BasicAAResult::getModRefBehavior(const CallBase *Call) {
+  FunctionModRefBehavior Min =
+      getModRefBehaviorFromAttrs(Call->getAttributes().getFnAttrs());
 
-  if (const Function *F = Call->getCalledFunction()) {
+  if (const Function *F = dyn_cast<Function>(Call->getCalledOperand())) {
     FunctionModRefBehavior FMRB = getBestAAResults().getModRefBehavior(F);
     // Operand bundles on the call may also read or write memory, in addition
     // to the behavior of the called function.
@@ -786,10 +788,6 @@ FunctionModRefBehavior BasicAAResult::getModRefBehavior(const CallBase *Call) {
 /// Returns the behavior when calling the given function. For use when the call
 /// site is not known.
 FunctionModRefBehavior BasicAAResult::getModRefBehavior(const Function *F) {
-  // If the function declares it doesn't access memory, we can't do better.
-  if (F->doesNotAccessMemory())
-    return FunctionModRefBehavior::none();
-
   switch (F->getIntrinsicID()) {
   case Intrinsic::experimental_guard:
   case Intrinsic::experimental_deoptimize:
@@ -799,20 +797,7 @@ FunctionModRefBehavior BasicAAResult::getModRefBehavior(const Function *F) {
            FunctionModRefBehavior::inaccessibleMemOnly(ModRefInfo::ModRef);
   }
 
-  // If the function declares it only reads memory, go with that.
-  ModRefInfo MR = ModRefInfo::ModRef;
-  if (F->onlyReadsMemory())
-    MR = ModRefInfo::Ref;
-  else if (F->onlyWritesMemory())
-    MR = ModRefInfo::Mod;
-
-  if (F->onlyAccessesArgMemory())
-    return FunctionModRefBehavior::argMemOnly(MR);
-  if (F->onlyAccessesInaccessibleMemory())
-    return FunctionModRefBehavior::inaccessibleMemOnly(MR);
-  if (F->onlyAccessesInaccessibleMemOrArgMem())
-    return FunctionModRefBehavior::inaccessibleOrArgMemOnly(MR);
-  return FunctionModRefBehavior(MR);
+  return getModRefBehaviorFromAttrs(F->getAttributes().getFnAttrs());
 }
 
 /// Returns true if this is a writeonly (i.e Mod only) parameter.