[PATCH] [InstCombine][X86] Improved folding of calls to Intrinsic::x86_sse4a_insertqi.

[David Majnemer]

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Comment at: lib/Transforms/InstCombine/InstCombineCalls.cpp:784
@@ +783,3 @@
+        // results are undefined.
+        if ((Index + Length) > 64)
+          return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
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Is there anything that prevents `Index + Length` from wrapping around? If not, what happens?

http://reviews.llvm.org/D6583