Integrate the readonly/readnone logic more deeply

into alias analysis.  This meant updating the API
which now has versions of the getModRefBehavior,
doesNotAccessMemory and onlyReadsMemory methods
which take a callsite parameter.  These should be
used unless the callsite is not known, since in
general they can do a better job than the versions
that take a function.  Also, users should no longer
call the version of getModRefBehavior that takes
both a function and a callsite.  To reduce the
chance of misuse it is now protected.

llvm-svn: 44487

4 files changed, 19 insertions, 27 deletions

diff --git a/llvm/lib/Transforms/Scalar/ADCE.cpp b/llvm/lib/Transforms/Scalar/ADCE.cpp
index e3bd3623ce2..7f373342100 100644
--- a/llvm/lib/Transforms/Scalar/ADCE.cpp
+++ b/llvm/lib/Transforms/Scalar/ADCE.cpp
@@ -198,8 +198,7 @@ bool ADCE::doADCE() {
     for (BasicBlock::iterator II = BB->begin(), EI = BB->end(); II != EI; ) {
       Instruction *I = II++;
       if (CallInst *CI = dyn_cast<CallInst>(I)) {
-        Function *F = CI->getCalledFunction();
-        if (F && AA.onlyReadsMemory(F)) {
+        if (AA.onlyReadsMemory(CI)) {
           if (CI->use_empty()) {
             BB->getInstList().erase(CI);
             ++NumCallRemoved;
diff --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
index b19077f1fcc..8e69d9ad689 100644
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -306,8 +306,7 @@ bool DSE::handleEndBlock(BasicBlock& BB,
       // If this call does not access memory, it can't
       // be undeadifying any of our pointers.
       CallSite CS = CallSite::get(BBI);
-      if (CS.getCalledFunction() &&
-          AA.doesNotAccessMemory(CS.getCalledFunction()))
+      if (AA.doesNotAccessMemory(CS))
         continue;
       
       unsigned modRef = 0;
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index 7799befb3c2..c3d59854c65 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -341,8 +341,7 @@ Expression::ExpressionOpcode
 
 uint32_t ValueTable::hash_operand(Value* v) {
   if (CallInst* CI = dyn_cast<CallInst>(v))
-    if (CI->getCalledFunction() &&
-        !AA->doesNotAccessMemory(CI->getCalledFunction()))
+    if (!AA->doesNotAccessMemory(CI))
       return nextValueNumber++;
   
   return lookup_or_add(v);
@@ -485,9 +484,7 @@ uint32_t ValueTable::lookup_or_add(Value* V) {
     return VI->second;
   
   if (CallInst* C = dyn_cast<CallInst>(V)) {
-    if (C->getCalledFunction() &&
-        (AA->doesNotAccessMemory(C->getCalledFunction()) ||
-         AA->onlyReadsMemory(C->getCalledFunction()))) {
+    if (AA->onlyReadsMemory(C)) { // includes doesNotAccessMemory
       Expression e = create_expression(C);
     
       DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
@@ -1051,8 +1048,7 @@ bool GVN::processInstruction(Instruction* I,
     
     if (CallInst* CI = dyn_cast<CallInst>(I)) {
       AliasAnalysis& AA = getAnalysis<AliasAnalysis>();
-      if (CI->getCalledFunction() &&
-          !AA.doesNotAccessMemory(CI->getCalledFunction())) {
+      if (!AA.doesNotAccessMemory(CI)) {
         MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>();
         if (cast<Instruction>(repl)->getParent() != CI->getParent() ||
             MD.getDependency(CI) != MD.getDependency(cast<CallInst>(repl))) {
diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index c86b4639489..0c8cb4d0273 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -375,24 +375,22 @@ bool LICM::canSinkOrHoistInst(Instruction &I) {
     return !pointerInvalidatedByLoop(LI->getOperand(0), Size);
   } else if (CallInst *CI = dyn_cast<CallInst>(&I)) {
     // Handle obvious cases efficiently.
-    if (Function *Callee = CI->getCalledFunction()) {
-      AliasAnalysis::ModRefBehavior Behavior =AA->getModRefBehavior(Callee, CI);
-      if (Behavior == AliasAnalysis::DoesNotAccessMemory)
-        return true;
-      else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
-        // If this call only reads from memory and there are no writes to memory
-        // in the loop, we can hoist or sink the call as appropriate.
-        bool FoundMod = false;
-        for (AliasSetTracker::iterator I = CurAST->begin(), E = CurAST->end();
-             I != E; ++I) {
-          AliasSet &AS = *I;
-          if (!AS.isForwardingAliasSet() && AS.isMod()) {
-            FoundMod = true;
-            break;
-          }
+    AliasAnalysis::ModRefBehavior Behavior = AA->getModRefBehavior(CI);
+    if (Behavior == AliasAnalysis::DoesNotAccessMemory)
+      return true;
+    else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
+      // If this call only reads from memory and there are no writes to memory
+      // in the loop, we can hoist or sink the call as appropriate.
+      bool FoundMod = false;
+      for (AliasSetTracker::iterator I = CurAST->begin(), E = CurAST->end();
+           I != E; ++I) {
+        AliasSet &AS = *I;
+        if (!AS.isForwardingAliasSet() && AS.isMod()) {
+          FoundMod = true;
+          break;
         }
-        if (!FoundMod) return true;
       }
+      if (!FoundMod) return true;
     }
 
     // FIXME: This should use mod/ref information to see if we can hoist or sink