diff --git a/llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index 1bc8a1e3ea82..db6500c930b2 100644
--- a/llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -903,9 +903,10 @@ void SROA::RewriteStoreUserOfWholeAlloca(StoreInst *SI,
   
   // If this isn't a store of an integer to the whole alloca, it may be a store
   // to the first element.  Just ignore the store in this case and normal SROA
-  // will handle it.
+  // will handle it.  We don't handle types here that have tail padding, like
+  // an alloca of type {i1}.
   if (!isa<IntegerType>(SrcVal->getType()) ||
-      TD->getTypePaddedSizeInBits(SrcVal->getType()) != AllocaSizeBits)
+      TD->getTypeSizeInBits(SrcVal->getType()) != AllocaSizeBits)
     return;
 
   DOUT << "PROMOTING STORE TO WHOLE ALLOCA: " << *AI << *SI;
@@ -1015,9 +1016,10 @@ void SROA::RewriteLoadUserOfWholeAlloca(LoadInst *LI, AllocationInst *AI,
   
   // If this isn't a load of the whole alloca to an integer, it may be a load
   // of the first element.  Just ignore the load in this case and normal SROA
-  // will handle it.
+  // will handle it.  We don't handle types here that have tail padding, like
+  // an alloca of type {i1}.
   if (!isa<IntegerType>(LI->getType()) ||
-      TD->getTypePaddedSizeInBits(LI->getType()) != AllocaSizeBits)
+      TD->getTypeSizeInBits(LI->getType()) != AllocaSizeBits)
     return;
   
   DOUT << "PROMOTING LOAD OF WHOLE ALLOCA: " << *AI << *LI;
diff --git a/llvm/test/Transforms/ScalarRepl/2009-05-08-I1Crash.ll b/llvm/test/Transforms/ScalarRepl/2009-05-08-I1Crash.ll
new file mode 100644
index 000000000000..0a604e9dcc3c
--- /dev/null
+++ b/llvm/test/Transforms/ScalarRepl/2009-05-08-I1Crash.ll
@@ -0,0 +1,12 @@
+; RUN: llvm-as < %s | opt -scalarrepl | llvm-dis
+; PR4146
+
+ %wrapper = type { i1 }
+
+define void @f() {
+entry:
+        %w = alloca %wrapper, align 8           ; <%wrapper*> [#uses=1]
+        %0 = getelementptr %wrapper* %w, i64 0, i32 0           ; <i1*>
+        store i1 true, i1* %0
+        ret void
+}