Index: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -10673,6 +10673,10 @@
   bool NoVectors = DAG.getMachineFunction().getFunction()->hasFnAttribute(
       Attribute::NoImplicitFloat);
 
+  // This function cannot currently deal with non-byte-sized memory sizes.
+  if (ElementSizeBytes * 8 != MemVT.getSizeInBits())
+    return false;
+
   // Don't merge vectors into wider inputs.
   if (MemVT.isVector() || !MemVT.isSimple())
     return false;
Index: llvm/trunk/test/CodeGen/X86/merge-consecutive-stores-i1.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/merge-consecutive-stores-i1.ll
+++ llvm/trunk/test/CodeGen/X86/merge-consecutive-stores-i1.ll
@@ -0,0 +1,15 @@
+; RUN: llc  -march=x86-64 < %s
+
+; Ensure that MergeConsecutiveStores doesn't crash when dealing with
+; i1 operands.
+
+%struct.X = type { i1, i1 }
+
+@b = common global %struct.X zeroinitializer, align 4
+
+define void @foo() {
+entry:
+  store i1 0, i1* getelementptr inbounds (%struct.X, %struct.X* @b, i64 0, i32 0), align 4
+  store i1 0, i1* getelementptr inbounds (%struct.X, %struct.X* @b, i64 0, i32 1), align 1
+  ret void
+}