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-rw-r--r--lib/VMCore/ConstantFold.cpp11
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index 2a96291fe4..703a324126 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -562,6 +562,17 @@ Constant *llvm::ConstantFoldCastInstruction(const Constant *V,
return ConstantExpr::getCast(CE->getOperand(0), DestTy);
}
+ // Check to see if we are casting an array of X to a pointer to X. If so, use
+ // a GEP to get to the first element of the array instead of a cast!
+ if (const PointerType *PTy = dyn_cast<PointerType>(V->getType()))
+ if (const ArrayType *ATy = dyn_cast<ArrayType>(PTy->getElementType()))
+ if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy))
+ if (DPTy->getElementType() == ATy->getElementType()) {
+ std::vector<Constant*> IdxList(2,Constant::getNullValue(Type::IntTy));
+ return ConstantExpr::getGetElementPtr(const_cast<Constant*>(V),
+ IdxList);
+ }
+
ConstRules &Rules = ConstRules::get(V, V);
switch (DestTy->getTypeID()) {