[PATCH] [Instcombine/InstSimplify] Move optimization from instcombine to instsimplify

[Nick Lewycky]

I made a few adjustments:

+    ConstantInt *C1 = nullptr, *C2 = nullptr;
+    C1 = dyn_cast<ConstantInt>(C);
+    C2 = dyn_cast<ConstantInt>(D);
became
+    ConstantInt *C1 = dyn_cast<ConstantInt>(C);
+    ConstantInt *C2 = dyn_cast<ConstantInt>(D);

I removed the dead initialization of V1 and V2 to nullptr. They aren't used
unless they match succeeds.

Your test had @test1 and @test3, renamed @test3 to @test2.

Changed test to use FileCheck instead of grep. I'm aware this is what
InstCombine/apint-or{1,2}.ll does, but it's an older style and FileCheck is
preferred.

Moved the whole-file comments that apply to each function ("the first
test..." and "the second test...") next to the functions they apply to.

Committed in r211252. Thanks!

Nick

http://reviews.llvm.org/D4100