[PATCH] [x86] instcombine more cases of insertps into a shufflevector

[Simon Pilgrim]

Thanks Sanjay, a minor suggested change to support a (dumb) edge case that zeros out the inserted lane.


================
Comment at: lib/Transforms/InstCombine/InstCombineCalls.cpp:232
@@ +231,3 @@
+      // shuffle with the zero vector.
+      if (II.getArgOperand(0) == II.getArgOperand(1)) {
+        V1 = ZeroVector;
----------------
A minor change would allow (silly) cases where the 2nd operand insertion has been zero'd away:

if ((II.getArgOperand(0) == II.getArgOperand(1)) || (Zmask & (1 << DestLane)))

http://reviews.llvm.org/D9257

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