LLVM Bug Fix 13709: Remove needless lsr(Rp, #32) instruction access the

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

diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index c6b53a927dbda8c74d7abb51fa3d59cdaa3235ba..491224a4b692cf0dbf18a87263bb991f135d998b 100644 (file)
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -564,7 +564,7 @@ void llvm::ComputeMaskedBits(Value *V, APInt &KnownZero, APInt &KnownOne,
                         Depth+1);
       // If it's known zero, our sign bit is also zero.
       if (LHSKnownZero.isNegative())
-        KnownZero |= LHSKnownZero;
+        KnownZero.setBit(BitWidth - 1);
     }
 
     break;
@@ -694,7 +694,7 @@ void llvm::ComputeMaskedBits(Value *V, APInt &KnownZero, APInt &KnownOne,
     // taking conservative care to avoid excessive recursion.
     if (Depth < MaxDepth - 1 && !KnownZero && !KnownOne) {
       // Skip if every incoming value references to ourself.
-      if (P->hasConstantValue() == P)
+      if (dyn_cast_or_null<UndefValue>(P->hasConstantValue()))
         break;
 
       KnownZero = APInt::getAllOnesValue(BitWidth);
@@ -1614,7 +1614,7 @@ Value *llvm::GetPointerBaseWithConstantOffset(Value *Ptr, int64_t &Offset,
   // right.
   unsigned PtrSize = TD.getPointerSizeInBits();
   if (PtrSize < 64)
-    Offset = (Offset << (64-PtrSize)) >> (64-PtrSize);
+    Offset = SignExtend64(Offset, PtrSize);
   
   return GetPointerBaseWithConstantOffset(GEP->getPointerOperand(), Offset, TD);
 }
@@ -1796,6 +1796,37 @@ llvm::GetUnderlyingObject(Value *V, const TargetData *TD, unsigned MaxLookup) {
   return V;
 }
 
+void
+llvm::GetUnderlyingObjects(Value *V,
+                           SmallVectorImpl<Value *> &Objects,
+                           const TargetData *TD,
+                           unsigned MaxLookup) {
+  SmallPtrSet<Value *, 4> Visited;
+  SmallVector<Value *, 4> Worklist;
+  Worklist.push_back(V);
+  do {
+    Value *P = Worklist.pop_back_val();
+    P = GetUnderlyingObject(P, TD, MaxLookup);
+
+    if (!Visited.insert(P))
+      continue;
+
+    if (SelectInst *SI = dyn_cast<SelectInst>(P)) {
+      Worklist.push_back(SI->getTrueValue());
+      Worklist.push_back(SI->getFalseValue());
+      continue;
+    }
+
+    if (PHINode *PN = dyn_cast<PHINode>(P)) {
+      for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+        Worklist.push_back(PN->getIncomingValue(i));
+      continue;
+    }
+
+    Objects.push_back(P);
+  } while (!Worklist.empty());
+}
+
 /// onlyUsedByLifetimeMarkers - Return true if the only users of this pointer
 /// are lifetime markers.
 ///
@@ -1854,6 +1885,14 @@ bool llvm::isSafeToSpeculativelyExecute(const Value *V,
   case Instruction::Call: {
    if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
      switch (II->getIntrinsicID()) {
+       // These synthetic intrinsics have no side-effects, and just mark
+       // information about their operands.
+       // FIXME: There are other no-op synthetic instructions that potentially
+       // should be considered at least *safe* to speculate...
+       case Intrinsic::dbg_declare:
+       case Intrinsic::dbg_value:
+         return true;
+
        case Intrinsic::bswap:
        case Intrinsic::ctlz:
        case Intrinsic::ctpop: