move GetPointerBaseWithConstantOffset out of GVN into ValueTracking.h

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

diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index e617ff2980db4f61d40713f7f5921776ff7d8297..87125191ad0e77f429e177add08af6e2148b9ce6 100644 (file)
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -8,8 +8,10 @@
 //===----------------------------------------------------------------------===//
 //
 // This file implements routines for folding instructions into simpler forms
-// that do not require creating new instructions.  For example, this does
-// constant folding, and can handle identities like (X&0)->0.
+// that do not require creating new instructions.  This does constant folding
+// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
+// returning a constant ("and i32 %x, 0" -> "0") or an already existing value
+// ("and i32 %x, %x" -> "%x").
 //
 //===----------------------------------------------------------------------===//
 
@@ -296,7 +298,7 @@ static Value *SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD,
     return Op0;
 
   // A & ~A  =  ~A & A  =  0
-  Value *A, *B;
+  Value *A = 0, *B = 0;
   if ((match(Op0, m_Not(m_Value(A))) && A == Op1) ||
       (match(Op1, m_Not(m_Value(A))) && A == Op0))
     return Constant::getNullValue(Op0->getType());
@@ -375,7 +377,7 @@ static Value *SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD,
     return Op1;
 
   // A | ~A  =  ~A | A  =  -1
-  Value *A, *B;
+  Value *A = 0, *B = 0;
   if ((match(Op0, m_Not(m_Value(A))) && A == Op1) ||
       (match(Op1, m_Not(m_Value(A))) && A == Op0))
     return Constant::getAllOnesValue(Op0->getType());
@@ -450,7 +452,7 @@ static Value *SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD,
     return Constant::getNullValue(Op0->getType());
 
   // A ^ ~A  =  ~A ^ A  =  -1
-  Value *A, *B;
+  Value *A = 0, *B = 0;
   if ((match(Op0, m_Not(m_Value(A))) && A == Op1) ||
       (match(Op1, m_Not(m_Value(A))) && A == Op0))
     return Constant::getAllOnesValue(Op0->getType());
@@ -714,7 +716,7 @@ Value *llvm::SimplifyGEPInst(Value *const *Ops, unsigned NumOps,
     // getelementptr P, N -> P if P points to a type of zero size.
     if (TD) {
       const Type *Ty = PtrTy->getElementType();
-      if (Ty->isSized() && !TD->getTypeAllocSize(Ty))
+      if (Ty->isSized() && TD->getTypeAllocSize(Ty) == 0)
         return Ops[0];
     }
   }