Factorize code: remove variants of "strip off

pointer bitcasts and GEP's", and centralize the
logic in Value::getUnderlyingObject.  The
difference with stripPointerCasts is that
stripPointerCasts only strips GEPs if all
indices are zero, while getUnderlyingObject
strips GEPs no matter what the indices are.

llvm-svn: 56922

1 files changed, 21 insertions, 8 deletions

diff --git a/llvm/lib/VMCore/Value.cpp b/llvm/lib/VMCore/Value.cpp
index d143b6bf97e..0976a745991 100644
--- a/llvm/lib/VMCore/Value.cpp
+++ b/llvm/lib/VMCore/Value.cpp
@@ -322,22 +322,20 @@ void Value::replaceAllUsesWith(Value *New) {
 }
 
 Value *Value::stripPointerCasts() {
+  if (!isa<PointerType>(getType()))
+    return this;
+
   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) {
     if (CE->getOpcode() == Instruction::BitCast) {
-      if (isa<PointerType>(CE->getOperand(0)->getType()))
-        return CE->getOperand(0)->stripPointerCasts();
+      return CE->getOperand(0)->stripPointerCasts();
     } else if (CE->getOpcode() == Instruction::GetElementPtr) {
       for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
         if (!CE->getOperand(i)->isNullValue())
           return this;
       return CE->getOperand(0)->stripPointerCasts();
     }
-    return this;
-  }
-
-  if (BitCastInst *CI = dyn_cast<BitCastInst>(this)) {
-    if (isa<PointerType>(CI->getOperand(0)->getType()))
-      return CI->getOperand(0)->stripPointerCasts();
+  } else if (BitCastInst *CI = dyn_cast<BitCastInst>(this)) {
+    return CI->getOperand(0)->stripPointerCasts();
   } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(this)) {
     if (GEP->hasAllZeroIndices())
       return GEP->getOperand(0)->stripPointerCasts();
@@ -345,6 +343,21 @@ Value *Value::stripPointerCasts() {
   return this;
 }
 
+Value *Value::getUnderlyingObject() {
+  if (!isa<PointerType>(getType()))
+    return this;
+
+  if (Instruction *I = dyn_cast<Instruction>(this)) {
+    if (isa<BitCastInst>(I) || isa<GetElementPtrInst>(I))
+      return I->getOperand(0)->getUnderlyingObject();
+  } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) {
+    if (CE->getOpcode() == Instruction::BitCast ||
+        CE->getOpcode() == Instruction::GetElementPtr)
+      return CE->getOperand(0)->getUnderlyingObject();
+  }
+  return this;
+}
+
 //===----------------------------------------------------------------------===//
 //                                 User Class
 //===----------------------------------------------------------------------===//