diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 5a6077a..0e719f8 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1102,14 +1102,8 @@
   }
   
   // fold (sub x, x) -> 0
-  if (N0 == N1) {
-    if (AfterLegalize && ISD::isBuildVectorAllZeros(N0.Val))
-      // For example, zero vectors might be normalized to a particular vector
-      // type to ensure they are CSE'd. Avoid issuing zero vector nodes of
-      // *unexpected* type after legalization.
-      return N0;
+  if (N0 == N1)
     return DAG.getConstant(0, N->getValueType(0));
-  }
   // fold (sub c1, c2) -> c1-c2
   if (N0C && N1C)
     return DAG.getNode(ISD::SUB, VT, N0, N1);
diff --git a/lib/Target/X86/X86InstrMMX.td b/lib/Target/X86/X86InstrMMX.td
index 65013b3..0a18fa5 100644
--- a/lib/Target/X86/X86InstrMMX.td
+++ b/lib/Target/X86/X86InstrMMX.td
@@ -510,6 +510,12 @@
                               [(set VR64:$dst, (v2i32 immAllOnesV))]>;
 }
 
+let Predicates = [HasMMX] in {
+  def : Pat<(v1i64 immAllZerosV), (MMX_V_SET0)>;
+  def : Pat<(v4i16 immAllZerosV), (MMX_V_SET0)>;
+  def : Pat<(v8i8  immAllZerosV), (MMX_V_SET0)>;
+}
+
 //===----------------------------------------------------------------------===//
 // Non-Instruction Patterns
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/X86/X86InstrSSE.td b/lib/Target/X86/X86InstrSSE.td
index 55d92bd..0ca9c69 100644
--- a/lib/Target/X86/X86InstrSSE.td
+++ b/lib/Target/X86/X86InstrSSE.td
@@ -969,6 +969,14 @@
                  "xorps\t$dst, $dst",
                  [(set VR128:$dst, (v4i32 immAllZerosV))]>;
 
+let Predicates = [HasSSE1] in {
+  def : Pat<(v2i64 immAllZerosV), (V_SET0)>;
+  def : Pat<(v8i16 immAllZerosV), (V_SET0)>;
+  def : Pat<(v16i8 immAllZerosV), (V_SET0)>;
+  def : Pat<(v2f64 immAllZerosV), (V_SET0)>;
+  def : Pat<(v4f32 immAllZerosV), (V_SET0)>;
+}
+
 // FR32 to 128-bit vector conversion.
 def MOVSS2PSrr : SSI<0x10, MRMSrcReg, (outs VR128:$dst), (ins FR32:$src),
                       "movss\t{$src, $dst|$dst, $src}",