X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FLint.cpp;h=2c8fc0bba4149608337e9b513d80cab531274bf8;hb=6a2f9b91379140c36a11ade6c0673bd7490eba32;hp=fd10a6b78348fdbb5d81d655bc9b6f98e913b76b;hpb=0b8c9a80f20772c3793201ab5b251d3520b9cea3;p=oota-llvm.git

diff --git a/lib/Analysis/Lint.cpp b/lib/Analysis/Lint.cpp
index fd10a6b7834..2c8fc0bba41 100644
--- a/lib/Analysis/Lint.cpp
+++ b/lib/Analysis/Lint.cpp
@@ -412,51 +412,49 @@ void Lint::visitMemoryReference(Instruction &I,
   }
 
   // Check for buffer overflows and misalignment.
-  if (TD) {
-    // Only handles memory references that read/write something simple like an
-    // alloca instruction or a global variable.
-    int64_t Offset = 0;
-    if (Value *Base = GetPointerBaseWithConstantOffset(Ptr, Offset, *TD)) {
-      // OK, so the access is to a constant offset from Ptr.  Check that Ptr is
-      // something we can handle and if so extract the size of this base object
-      // along with its alignment.
-      uint64_t BaseSize = AliasAnalysis::UnknownSize;
-      unsigned BaseAlign = 0;
-
-      if (AllocaInst *AI = dyn_cast<AllocaInst>(Base)) {
-        Type *ATy = AI->getAllocatedType();
-        if (!AI->isArrayAllocation() && ATy->isSized())
-          BaseSize = TD->getTypeAllocSize(ATy);
-        BaseAlign = AI->getAlignment();
-        if (BaseAlign == 0 && ATy->isSized())
-          BaseAlign = TD->getABITypeAlignment(ATy);
-      } else if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Base)) {
-        // If the global may be defined differently in another compilation unit
-        // then don't warn about funky memory accesses.
-        if (GV->hasDefinitiveInitializer()) {
-          Type *GTy = GV->getType()->getElementType();
-          if (GTy->isSized())
-            BaseSize = TD->getTypeAllocSize(GTy);
-          BaseAlign = GV->getAlignment();
-          if (BaseAlign == 0 && GTy->isSized())
-            BaseAlign = TD->getABITypeAlignment(GTy);
-        }
+  // Only handles memory references that read/write something simple like an
+  // alloca instruction or a global variable.
+  int64_t Offset = 0;
+  if (Value *Base = GetPointerBaseWithConstantOffset(Ptr, Offset, TD)) {
+    // OK, so the access is to a constant offset from Ptr.  Check that Ptr is
+    // something we can handle and if so extract the size of this base object
+    // along with its alignment.
+    uint64_t BaseSize = AliasAnalysis::UnknownSize;
+    unsigned BaseAlign = 0;
+
+    if (AllocaInst *AI = dyn_cast<AllocaInst>(Base)) {
+      Type *ATy = AI->getAllocatedType();
+      if (TD && !AI->isArrayAllocation() && ATy->isSized())
+        BaseSize = TD->getTypeAllocSize(ATy);
+      BaseAlign = AI->getAlignment();
+      if (TD && BaseAlign == 0 && ATy->isSized())
+        BaseAlign = TD->getABITypeAlignment(ATy);
+    } else if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Base)) {
+      // If the global may be defined differently in another compilation unit
+      // then don't warn about funky memory accesses.
+      if (GV->hasDefinitiveInitializer()) {
+        Type *GTy = GV->getType()->getElementType();
+        if (TD && GTy->isSized())
+          BaseSize = TD->getTypeAllocSize(GTy);
+        BaseAlign = GV->getAlignment();
+        if (TD && BaseAlign == 0 && GTy->isSized())
+          BaseAlign = TD->getABITypeAlignment(GTy);
       }
-
-      // Accesses from before the start or after the end of the object are not
-      // defined.
-      Assert1(Size == AliasAnalysis::UnknownSize ||
-              BaseSize == AliasAnalysis::UnknownSize ||
-              (Offset >= 0 && Offset + Size <= BaseSize),
-              "Undefined behavior: Buffer overflow", &I);
-
-      // Accesses that say that the memory is more aligned than it is are not
-      // defined.
-      if (Align == 0 && Ty && Ty->isSized())
-        Align = TD->getABITypeAlignment(Ty);
-      Assert1(!BaseAlign || Align <= MinAlign(BaseAlign, Offset),
-              "Undefined behavior: Memory reference address is misaligned", &I);
     }
+
+    // Accesses from before the start or after the end of the object are not
+    // defined.
+    Assert1(Size == AliasAnalysis::UnknownSize ||
+            BaseSize == AliasAnalysis::UnknownSize ||
+            (Offset >= 0 && Offset + Size <= BaseSize),
+            "Undefined behavior: Buffer overflow", &I);
+
+    // Accesses that say that the memory is more aligned than it is are not
+    // defined.
+    if (TD && Align == 0 && Ty && Ty->isSized())
+      Align = TD->getABITypeAlignment(Ty);
+    Assert1(!BaseAlign || Align <= MinAlign(BaseAlign, Offset),
+            "Undefined behavior: Memory reference address is misaligned", &I);
   }
 }
 
@@ -506,14 +504,42 @@ void Lint::visitShl(BinaryOperator &I) {
             "Undefined result: Shift count out of range", &I);
 }
 
-static bool isZero(Value *V, DataLayout *TD) {
+static bool isZero(Value *V, DataLayout *DL) {
   // Assume undef could be zero.
-  if (isa<UndefValue>(V)) return true;
+  if (isa<UndefValue>(V))
+    return true;
+
+  VectorType *VecTy = dyn_cast<VectorType>(V->getType());
+  if (!VecTy) {
+    unsigned BitWidth = V->getType()->getIntegerBitWidth();
+    APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
+    ComputeMaskedBits(V, KnownZero, KnownOne, DL);
+    return KnownZero.isAllOnesValue();
+  }
 
-  unsigned BitWidth = cast<IntegerType>(V->getType())->getBitWidth();
-  APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
-  ComputeMaskedBits(V, KnownZero, KnownOne, TD);
-  return KnownZero.isAllOnesValue();
+  // Per-component check doesn't work with zeroinitializer
+  Constant *C = dyn_cast<Constant>(V);
+  if (!C)
+    return false;
+
+  if (C->isZeroValue())
+    return true;
+
+  // For a vector, KnownZero will only be true if all values are zero, so check
+  // this per component
+  unsigned BitWidth = VecTy->getElementType()->getIntegerBitWidth();
+  for (unsigned I = 0, N = VecTy->getNumElements(); I != N; ++I) {
+    Constant *Elem = C->getAggregateElement(I);
+    if (isa<UndefValue>(Elem))
+      return true;
+
+    APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
+    ComputeMaskedBits(Elem, KnownZero, KnownOne, DL);
+    if (KnownZero.isAllOnesValue())
+      return true;
+  }
+
+  return false;
 }
 
 void Lint::visitSDiv(BinaryOperator &I) {