Remove the code which constant-folded ptrtoint(inttoptr(x)+c) to

getelementptr. Despite only doing so in the case where x is a known
array object and c can be converted to an index within range, this
could still be invalid if c is actually the address of an object
allocated outside of LLVM. Also, SCEVExpander, the original motivation
for this code, has since been improved to avoid inttoptr+ptroint in
more cases.

llvm-svn: 96950

1 files changed, 5 insertions, 37 deletions

diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 1d23fe0b6c9..114db2d3705 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -783,44 +783,12 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
     // If the input is a ptrtoint, turn the pair into a ptr to ptr bitcast if
     // the int size is >= the ptr size.  This requires knowing the width of a
     // pointer, so it can't be done in ConstantExpr::getCast.
-    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0])) {
+    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0]))
       if (TD &&
-          TD->getPointerSizeInBits() <=
-          CE->getType()->getScalarSizeInBits()) {
-        if (CE->getOpcode() == Instruction::PtrToInt)
-          return FoldBitCast(CE->getOperand(0), DestTy, *TD);
-        
-        // If there's a constant offset added to the integer value before
-        // it is casted back to a pointer, see if the expression can be
-        // converted into a GEP.
-        if (CE->getOpcode() == Instruction::Add)
-          if (ConstantInt *L = dyn_cast<ConstantInt>(CE->getOperand(1)))
-            if (ConstantExpr *R = dyn_cast<ConstantExpr>(CE->getOperand(0)))
-              if (R->getOpcode() == Instruction::PtrToInt)
-                if (GlobalVariable *GV =
-                      dyn_cast<GlobalVariable>(R->getOperand(0))) {
-                  const PointerType *GVTy = cast<PointerType>(GV->getType());
-                  if (const ArrayType *AT =
-                        dyn_cast<ArrayType>(GVTy->getElementType())) {
-                    const Type *ElTy = AT->getElementType();
-                    uint64_t AllocSize = TD->getTypeAllocSize(ElTy);
-                    APInt PSA(L->getValue().getBitWidth(), AllocSize);
-                    if (ElTy == cast<PointerType>(DestTy)->getElementType() &&
-                        L->getValue().urem(PSA) == 0) {
-                      APInt ElemIdx = L->getValue().udiv(PSA);
-                      if (ElemIdx.ult(APInt(ElemIdx.getBitWidth(),
-                                            AT->getNumElements()))) {
-                        Constant *Index[] = {
-                          Constant::getNullValue(CE->getType()),
-                          ConstantInt::get(ElTy->getContext(), ElemIdx)
-                        };
-                        return ConstantExpr::getGetElementPtr(GV, &Index[0], 2);
-                      }
-                    }
-                  }
-                }
-      }
-    }
+          TD->getPointerSizeInBits() <= CE->getType()->getScalarSizeInBits() &&
+          CE->getOpcode() == Instruction::PtrToInt)
+        return FoldBitCast(CE->getOperand(0), DestTy, *TD);
+
     return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
   case Instruction::Trunc:
   case Instruction::ZExt: