1 files changed, 9 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 005f1a0bc4f..90ab4f43df0 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -197,6 +197,9 @@ static void ComputeUnsignedMinMaxValuesFromKnownBits(const APInt &KnownZero,
 Instruction *InstCombiner::
 FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP, GlobalVariable *GV,
                              CmpInst &ICI, ConstantInt *AndCst) {
+  // We need TD information to know the pointer size unless this is inbounds.
+  if (!GEP->isInBounds() && TD == 0) return 0;
+  
   ConstantArray *Init = dyn_cast<ConstantArray>(GV->getInitializer());
   if (Init == 0 || Init->getNumOperands() > 1024) return 0;
   
@@ -354,6 +357,12 @@ FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP, GlobalVariable *GV,
   // order the state machines in complexity of the generated code.
   Value *Idx = GEP->getOperand(2);
 
+  // If the index is larger than the pointer size of the target, truncate the
+  // index down like the GEP would do implicitly.  We don't have to do this for
+  // an inbounds GEP because the index can't be out of range.
+  if (!GEP->isInBounds() &&
+      Idx->getType()->getPrimitiveSizeInBits() > TD->getPointerSizeInBits())
+    Idx = Builder->CreateTrunc(Idx, TD->getIntPtrType(Idx->getContext()));
   
   // If the comparison is only true for one or two elements, emit direct
   // comparisons.