Misc analysis passes that need to be aware of atomic load/store.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137650 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 50 insertions, 19 deletions

diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp
index bfa02e0e1f..73cc903721 100644
--- a/lib/Analysis/AliasAnalysis.cpp
+++ b/lib/Analysis/AliasAnalysis.cpp
@@ -268,8 +268,8 @@ AliasAnalysis::getLocationForDest(const MemIntrinsic *MTI) {
 
 AliasAnalysis::ModRefResult
 AliasAnalysis::getModRefInfo(const LoadInst *L, const Location &Loc) {
-  // Be conservative in the face of volatile.
-  if (L->isVolatile())
+  // Be conservative in the face of volatile/atomic.
+  if (!L->isUnordered())
     return ModRef;
 
   // If the load address doesn't alias the given address, it doesn't read
@@ -283,8 +283,8 @@ AliasAnalysis::getModRefInfo(const LoadInst *L, const Location &Loc) {
 
 AliasAnalysis::ModRefResult
 AliasAnalysis::getModRefInfo(const StoreInst *S, const Location &Loc) {
-  // Be conservative in the face of volatile.
-  if (S->isVolatile())
+  // Be conservative in the face of volatile/atomic.
+  if (!S->isUnordered())
     return ModRef;
 
   // If the store address cannot alias the pointer in question, then the
diff --git a/lib/Analysis/LoopDependenceAnalysis.cpp b/lib/Analysis/LoopDependenceAnalysis.cpp
index c1afe8fbd6..3997ac478b 100644
--- a/lib/Analysis/LoopDependenceAnalysis.cpp
+++ b/lib/Analysis/LoopDependenceAnalysis.cpp
@@ -76,7 +76,13 @@ static void GetMemRefInstrs(const Loop *L,
 }
 
 static bool IsLoadOrStoreInst(Value *I) {
-  return isa<LoadInst>(I) || isa<StoreInst>(I);
+  // Returns true if the load or store can be analyzed. Atomic and volatile
+  // operations have properties which this analysis does not understand.
+  if (LoadInst *LI = dyn_cast<LoadInst>(I))
+    return LI->isUnordered();
+  else if (StoreInst *SI = dyn_cast<StoreInst>(I))
+    return SI->isUnordered();
+  return false;
 }
 
 static Value *GetPointerOperand(Value *I) {
diff --git a/lib/Analysis/MemDepPrinter.cpp b/lib/Analysis/MemDepPrinter.cpp
index 2283db0bc4..dc40da012c 100644
--- a/lib/Analysis/MemDepPrinter.cpp
+++ b/lib/Analysis/MemDepPrinter.cpp
@@ -102,12 +102,21 @@ bool MemDepPrinter::runOnFunction(Function &F) {
     } else {
       SmallVector<NonLocalDepResult, 4> NLDI;
       if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
-        // FIXME: Volatile is not handled properly here.
+        if (!LI->isUnordered()) {
+          // FIXME: Handle atomic/volatile loads.
+          Deps[Inst].insert(std::make_pair(InstAndClobberFlag(0, false),
+                                           static_cast<BasicBlock *>(0)));
+          continue;
+        }
         AliasAnalysis::Location Loc = AA.getLocation(LI);
-        MDA.getNonLocalPointerDependency(Loc, !LI->isVolatile(),
-                                         LI->getParent(), NLDI);
+        MDA.getNonLocalPointerDependency(Loc, true, LI->getParent(), NLDI);
       } else if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
-        // FIXME: Volatile is not handled properly here.
+        if (!LI->isUnordered()) {
+          // FIXME: Handle atomic/volatile stores.
+          Deps[Inst].insert(std::make_pair(InstAndClobberFlag(0, false),
+                                           static_cast<BasicBlock *>(0)));
+          continue;
+        }
         AliasAnalysis::Location Loc = AA.getLocation(SI);
         MDA.getNonLocalPointerDependency(Loc, false, SI->getParent(), NLDI);
       } else if (VAArgInst *VI = dyn_cast<VAArgInst>(Inst)) {
diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index 34ba92509e..cdff85a513 100644
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -120,21 +120,27 @@ AliasAnalysis::ModRefResult GetLocation(const Instruction *Inst,
                                         AliasAnalysis::Location &Loc,
                                         AliasAnalysis *AA) {
   if (const LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
-    if (LI->isVolatile()) {
-      Loc = AliasAnalysis::Location();
+    if (LI->isUnordered()) {
+      Loc = AA->getLocation(LI);
+      return AliasAnalysis::Ref;
+    } else if (LI->getOrdering() == Monotonic) {
+      Loc = AA->getLocation(LI);
       return AliasAnalysis::ModRef;
     }
-    Loc = AA->getLocation(LI);
-    return AliasAnalysis::Ref;
+    Loc = AliasAnalysis::Location();
+    return AliasAnalysis::ModRef;
   }
 
   if (const StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
-    if (SI->isVolatile()) {
-      Loc = AliasAnalysis::Location();
+    if (SI->isUnordered()) {
+      Loc = AA->getLocation(SI);
+      return AliasAnalysis::Mod;
+    } else if (SI->getOrdering() == Monotonic) {
+      Loc = AA->getLocation(SI);
       return AliasAnalysis::ModRef;
     }
-    Loc = AA->getLocation(SI);
-    return AliasAnalysis::Mod;
+    Loc = AliasAnalysis::Location();
+    return AliasAnalysis::ModRef;
   }
 
   if (const VAArgInst *V = dyn_cast<VAArgInst>(Inst)) {
@@ -270,8 +276,8 @@ unsigned MemoryDependenceAnalysis::
 getLoadLoadClobberFullWidthSize(const Value *MemLocBase, int64_t MemLocOffs,
                                 unsigned MemLocSize, const LoadInst *LI,
                                 const TargetData &TD) {
-  // We can only extend non-volatile integer loads.
-  if (!isa<IntegerType>(LI->getType()) || LI->isVolatile()) return 0;
+  // We can only extend simple integer loads.
+  if (!isa<IntegerType>(LI->getType()) || !LI->isSimple()) return 0;
   
   // Get the base of this load.
   int64_t LIOffs = 0;
@@ -369,6 +375,11 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad,
     // Values depend on loads if the pointers are must aliased.  This means that
     // a load depends on another must aliased load from the same value.
     if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
+      // Atomic loads have complications involved.
+      // FIXME: This is overly conservative.
+      if (!LI->isUnordered())
+        return MemDepResult::getClobber(LI);
+
       AliasAnalysis::Location LoadLoc = AA->getLocation(LI);
       
       // If we found a pointer, check if it could be the same as our pointer.
@@ -424,6 +435,11 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad,
     }
     
     if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
+      // Atomic stores have complications involved.
+      // FIXME: This is overly conservative.
+      if (!SI->isUnordered())
+        return MemDepResult::getClobber(SI);
+
       // If alias analysis can tell that this store is guaranteed to not modify
       // the query pointer, ignore it.  Use getModRefInfo to handle cases where
       // the query pointer points to constant memory etc.