Index: lib/Transforms/Scalar/GVN.cpp
===================================================================
--- lib/Transforms/Scalar/GVN.cpp
+++ lib/Transforms/Scalar/GVN.cpp
@@ -1045,8 +1045,15 @@
 
   Value *DepPtr = DepLI->getPointerOperand();
   uint64_t DepSize = DL.getTypeSizeInBits(DepLI->getType());
-  int R = AnalyzeLoadFromClobberingWrite(LoadTy, LoadPtr, DepPtr, DepSize, DL);
-  if (R != -1) return R;
+  int Offset = AnalyzeLoadFromClobberingWrite(LoadTy, LoadPtr, DepPtr, DepSize, DL);
+  if (Offset != -1) {
+    // If the size is too large and we will have to widen, ensure we pass the
+    // widening rules below
+    unsigned SrcValSize = DL.getTypeStoreSize(DepLI->getType());
+    unsigned LoadSize = DL.getTypeStoreSize(LoadTy);
+    if (Offset + LoadSize <= SrcValSize)
+      return Offset;
+  }
 
   // If we have a load/load clobber an DepLI can be widened to cover this load,
   // then we should widen it!