vendor/llvm/llvm-trunk-r321414

1 files changed, 46 insertions, 10 deletions

diff --git a/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index 9c870b42a747..6af3fef963dc 100644
--- a/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -476,22 +476,33 @@ Instruction *MemCpyOptPass::tryMergingIntoMemset(Instruction *StartInst,
       Alignment = DL.getABITypeAlignment(EltType);
     }
 
-    AMemSet =
-      Builder.CreateMemSet(StartPtr, ByteVal, Range.End-Range.Start, Alignment);
+    // Remember the debug location.
+    DebugLoc Loc;
+    if (!Range.TheStores.empty())
+      Loc = Range.TheStores[0]->getDebugLoc();
 
     DEBUG(dbgs() << "Replace stores:\n";
           for (Instruction *SI : Range.TheStores)
-            dbgs() << *SI << '\n';
-          dbgs() << "With: " << *AMemSet << '\n');
-
-    if (!Range.TheStores.empty())
-      AMemSet->setDebugLoc(Range.TheStores[0]->getDebugLoc());
+            dbgs() << *SI << '\n');
 
     // Zap all the stores.
     for (Instruction *SI : Range.TheStores) {
       MD->removeInstruction(SI);
       SI->eraseFromParent();
     }
+
+    // Create the memset after removing the stores, so that if there any cached
+    // non-local dependencies on the removed instructions in
+    // MemoryDependenceAnalysis, the cache entries are updated to "dirty"
+    // entries pointing below the memset, so subsequent queries include the
+    // memset.
+    AMemSet =
+      Builder.CreateMemSet(StartPtr, ByteVal, Range.End-Range.Start, Alignment);
+    if (!Range.TheStores.empty())
+      AMemSet->setDebugLoc(Loc);
+
+    DEBUG(dbgs() << "With: " << *AMemSet << '\n');
+
     ++NumMemSetInfer;
   }
 
@@ -1031,9 +1042,22 @@ bool MemCpyOptPass::processMemCpyMemCpyDependence(MemCpyInst *M,
   //
   // NOTE: This is conservative, it will stop on any read from the source loc,
   // not just the defining memcpy.
-  MemDepResult SourceDep =
-      MD->getPointerDependencyFrom(MemoryLocation::getForSource(MDep), false,
-                                   M->getIterator(), M->getParent());
+  MemoryLocation SourceLoc = MemoryLocation::getForSource(MDep);
+  MemDepResult SourceDep = MD->getPointerDependencyFrom(SourceLoc, false,
+                                                        M->getIterator(), M->getParent());
+
+  if (SourceDep.isNonLocal()) {
+    SmallVector<NonLocalDepResult, 2> NonLocalDepResults;
+    MD->getNonLocalPointerDependencyFrom(M, SourceLoc, /*isLoad=*/false,
+                                         NonLocalDepResults);
+    if (NonLocalDepResults.size() == 1) {
+      SourceDep = NonLocalDepResults[0].getResult();
+      assert((!SourceDep.getInst() ||
+              LookupDomTree().dominates(SourceDep.getInst(), M)) &&
+             "when memdep returns exactly one result, it should dominate");
+    }
+  }
+
   if (!SourceDep.isClobber() || SourceDep.getInst() != MDep)
     return false;
 
@@ -1235,6 +1259,18 @@ bool MemCpyOptPass::processMemCpy(MemCpyInst *M) {
   MemDepResult SrcDepInfo = MD->getPointerDependencyFrom(
       SrcLoc, true, M->getIterator(), M->getParent());
 
+  if (SrcDepInfo.isNonLocal()) {
+    SmallVector<NonLocalDepResult, 2> NonLocalDepResults;
+    MD->getNonLocalPointerDependencyFrom(M, SrcLoc, /*isLoad=*/true,
+                                         NonLocalDepResults);
+    if (NonLocalDepResults.size() == 1) {
+      SrcDepInfo = NonLocalDepResults[0].getResult();
+      assert((!SrcDepInfo.getInst() ||
+              LookupDomTree().dominates(SrcDepInfo.getInst(), M)) &&
+             "when memdep returns exactly one result, it should dominate");
+    }
+  }
+
   if (SrcDepInfo.isClobber()) {
     if (MemCpyInst *MDep = dyn_cast<MemCpyInst>(SrcDepInfo.getInst()))
       return processMemCpyMemCpyDependence(M, MDep);