IR: Factor out replaceUsesOfWithOnConstantImpl(), NFC

[oota-llvm.git] / lib / Analysis / MemoryDependenceAnalysis.cpp

diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index 9eaf10958694335a3bd4ce1ad6a89783470c5780..8f22b0ed3de3dd6dfd99ee49430ed9ea8d698715 100644 (file)
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -158,29 +158,32 @@ AliasAnalysis::ModRefResult GetLocation(const Instruction *Inst,
     return AliasAnalysis::Mod;
   }
 
-  if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst))
+  if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
+    AAMDNodes AAInfo;
+
     switch (II->getIntrinsicID()) {
     case Intrinsic::lifetime_start:
     case Intrinsic::lifetime_end:
     case Intrinsic::invariant_start:
+      II->getAAMetadata(AAInfo);
       Loc = AliasAnalysis::Location(II->getArgOperand(1),
                                     cast<ConstantInt>(II->getArgOperand(0))
-                                      ->getZExtValue(),
-                                    II->getMetadata(LLVMContext::MD_tbaa));
+                                      ->getZExtValue(), AAInfo);
       // These intrinsics don't really modify the memory, but returning Mod
       // will allow them to be handled conservatively.
       return AliasAnalysis::Mod;
     case Intrinsic::invariant_end:
+      II->getAAMetadata(AAInfo);
       Loc = AliasAnalysis::Location(II->getArgOperand(2),
                                     cast<ConstantInt>(II->getArgOperand(1))
-                                      ->getZExtValue(),
-                                    II->getMetadata(LLVMContext::MD_tbaa));
+                                      ->getZExtValue(), AAInfo);
       // These intrinsics don't really modify the memory, but returning Mod
       // will allow them to be handled conservatively.
       return AliasAnalysis::Mod;
     default:
       break;
     }
+  }
 
   // Otherwise, just do the coarse-grained thing that always works.
   if (Inst->mayWriteToMemory())
@@ -404,10 +407,31 @@ 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.
+    // One exception is atomic loads: a value can depend on an atomic load that it
+    // does not alias with when this atomic load indicates that another thread may
+    // be accessing the location.
     if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
       // Atomic loads have complications involved.
+      // A monotonic load is OK if the query inst is itself not atomic.
       // FIXME: This is overly conservative.
-      if (!LI->isUnordered())
+      if (!LI->isUnordered()) {
+        if (!QueryInst)
+          return MemDepResult::getClobber(LI);
+        if (LI->getOrdering() != Monotonic)
+          return MemDepResult::getClobber(LI);
+        if (auto *QueryLI = dyn_cast<LoadInst>(QueryInst))
+          if (!QueryLI->isSimple())
+            return MemDepResult::getClobber(LI);
+        if (auto *QuerySI = dyn_cast<StoreInst>(QueryInst))
+          if (!QuerySI->isSimple())
+            return MemDepResult::getClobber(LI);
+      }
+
+      // FIXME: this is overly conservative.
+      // While volatile access cannot be eliminated, they do not have to clobber
+      // non-aliasing locations, as normal accesses can for example be reordered
+      // with volatile accesses.
+      if (LI->isVolatile())
         return MemDepResult::getClobber(LI);
 
       AliasAnalysis::Location LoadLoc = AA->getLocation(LI);
@@ -466,8 +490,26 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad,
 
     if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
       // Atomic stores have complications involved.
+      // A monotonic store is OK if the query inst is itself not atomic.
       // FIXME: This is overly conservative.
-      if (!SI->isUnordered())
+      if (!SI->isUnordered()) {
+        if (!QueryInst)
+          return MemDepResult::getClobber(SI);
+        if (SI->getOrdering() != Monotonic)
+          return MemDepResult::getClobber(SI);
+        if (auto *QueryLI = dyn_cast<LoadInst>(QueryInst))
+          if (!QueryLI->isSimple())
+            return MemDepResult::getClobber(SI);
+        if (auto *QuerySI = dyn_cast<StoreInst>(QueryInst))
+          if (!QuerySI->isSimple())
+            return MemDepResult::getClobber(SI);
+      }
+
+      // FIXME: this is overly conservative.
+      // While volatile access cannot be eliminated, they do not have to clobber
+      // non-aliasing locations, as normal accesses can for example be reordered
+      // with volatile accesses.
+      if (SI->isVolatile())
         return MemDepResult::getClobber(SI);
 
       // If alias analysis can tell that this store is guaranteed to not modify
@@ -922,10 +964,10 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer,
   // Set up a temporary NLPI value. If the map doesn't yet have an entry for
   // CacheKey, this value will be inserted as the associated value. Otherwise,
   // it'll be ignored, and we'll have to check to see if the cached size and
-  // tbaa tag are consistent with the current query.
+  // aa tags are consistent with the current query.
   NonLocalPointerInfo InitialNLPI;
   InitialNLPI.Size = Loc.Size;
-  InitialNLPI.TBAATag = Loc.TBAATag;
+  InitialNLPI.AATags = Loc.AATags;
 
   // Get the NLPI for CacheKey, inserting one into the map if it doesn't
   // already have one.
@@ -955,21 +997,21 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer,
                                          SkipFirstBlock);
     }
 
-    // If the query's TBAATag is inconsistent with the cached one,
+    // If the query's AATags are inconsistent with the cached one,
     // conservatively throw out the cached data and restart the query with
     // no tag if needed.
-    if (CacheInfo->TBAATag != Loc.TBAATag) {
-      if (CacheInfo->TBAATag) {
+    if (CacheInfo->AATags != Loc.AATags) {
+      if (CacheInfo->AATags) {
         CacheInfo->Pair = BBSkipFirstBlockPair();
-        CacheInfo->TBAATag = nullptr;
+        CacheInfo->AATags = AAMDNodes();
         for (NonLocalDepInfo::iterator DI = CacheInfo->NonLocalDeps.begin(),
              DE = CacheInfo->NonLocalDeps.end(); DI != DE; ++DI)
           if (Instruction *Inst = DI->getResult().getInst())
             RemoveFromReverseMap(ReverseNonLocalPtrDeps, Inst, CacheKey);
         CacheInfo->NonLocalDeps.clear();
       }
-      if (Loc.TBAATag)
-        return getNonLocalPointerDepFromBB(Pointer, Loc.getWithoutTBAATag(),
+      if (Loc.AATags)
+        return getNonLocalPointerDepFromBB(Pointer, Loc.getWithoutAATags(),
                                            isLoad, StartBB, Result, Visited,
                                            SkipFirstBlock);
     }