[PATCH] Optimization for certain shufflevector by using insertps.

[Sean Silva]

================
Comment at: lib/Target/X86/X86ISelLowering.cpp:3938
@@ +3937,3 @@
+  unsigned CorrectPosV2 = 0;
+  for (int i = 0; i < (int)VT.getVectorNumElements(); ++i)
+    if (Mask[i] == i)
----------------
Tiny style nit: the canonical LLVM counted loop is
```
for (int i = 0, e = Foo.size(); i != e; ++i)
```

http://reviews.llvm.org/D3475