[SeparateConstOffsetFromGEP] Allow SeparateConstOffsetFromGEP pass to lower GEPs.

[oota-llvm.git] / lib / Transforms / Scalar / MemCpyOptimizer.cpp

diff --git a/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index c750ece41b4def95252e161247e4e5aa9ba878bc..be524be0082af01c6aae8c492f8f5b0065f84f05 100644 (file)
--- a/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -16,6 +16,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/DataLayout.h"
@@ -329,6 +330,7 @@ namespace {
     // This transformation requires dominator postdominator info
     void getAnalysisUsage(AnalysisUsage &AU) const override {
       AU.setPreservesCFG();
+      AU.addRequired<AssumptionTracker>();
       AU.addRequired<DominatorTreeWrapperPass>();
       AU.addRequired<MemoryDependenceAnalysis>();
       AU.addRequired<AliasAnalysis>();
@@ -361,6 +363,7 @@ FunctionPass *llvm::createMemCpyOptPass() { return new MemCpyOpt(); }
 
 INITIALIZE_PASS_BEGIN(MemCpyOpt, "memcpyopt", "MemCpy Optimization",
                       false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(MemoryDependenceAnalysis)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
@@ -631,22 +634,24 @@ bool MemCpyOpt::performCallSlotOptzn(Instruction *cpy,
     if (destSize < srcSize)
       return false;
   } else if (Argument *A = dyn_cast<Argument>(cpyDest)) {
-    // If the destination is an sret parameter then only accesses that are
-    // outside of the returned struct type can trap.
-    if (!A->hasStructRetAttr())
-      return false;
+    if (A->getDereferenceableBytes() < srcSize) {
+      // If the destination is an sret parameter then only accesses that are
+      // outside of the returned struct type can trap.
+      if (!A->hasStructRetAttr())
+        return false;
 
-    Type *StructTy = cast<PointerType>(A->getType())->getElementType();
-    if (!StructTy->isSized()) {
-      // The call may never return and hence the copy-instruction may never
-      // be executed, and therefore it's not safe to say "the destination
-      // has at least <cpyLen> bytes, as implied by the copy-instruction",
-      return false;
-    }
+      Type *StructTy = cast<PointerType>(A->getType())->getElementType();
+      if (!StructTy->isSized()) {
+        // The call may never return and hence the copy-instruction may never
+        // be executed, and therefore it's not safe to say "the destination
+        // has at least <cpyLen> bytes, as implied by the copy-instruction",
+        return false;
+      }
 
-    uint64_t destSize = DL->getTypeAllocSize(StructTy);
-    if (destSize < srcSize)
-      return false;
+      uint64_t destSize = DL->getTypeAllocSize(StructTy);
+      if (destSize < srcSize)
+        return false;
+    }
   } else {
     return false;
   }
@@ -977,8 +982,11 @@ bool MemCpyOpt::processByValArgument(CallSite CS, unsigned ArgNo) {
 
   // If it is greater than the memcpy, then we check to see if we can force the
   // source of the memcpy to the alignment we need.  If we fail, we bail out.
+  AssumptionTracker *AT = &getAnalysis<AssumptionTracker>();
+  DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
   if (MDep->getAlignment() < ByValAlign &&
-      getOrEnforceKnownAlignment(MDep->getSource(),ByValAlign, DL) < ByValAlign)
+      getOrEnforceKnownAlignment(MDep->getSource(),ByValAlign,
+                                 DL, AT, CS.getInstruction(), &DT) < ByValAlign)
     return false;
 
   // Verify that the copied-from memory doesn't change in between the memcpy and