[PATCH] [InstCombine] call SimplifyICmpInst with correct context

[Jingyue Wu]

And just to be clear, I agree with you that it's a potential issue that `ComputeSignBit` is unable to say "I don't have a context". But my concern is, even if we fix that issue, not passing the context instruction to `SimplifyICmpInst` at all in `InstCombine` may overkill some useful optimizations.

Btw, I noticed that `SimplifyDemandedBits` indeed pass `UserI` as the context instruction (http://llvm.org/docs/doxygen/html/InstCombineSimplifyDemanded_8cpp_source.html#l00075), which seems aligned with the approach in my patch.


http://reviews.llvm.org/D10695

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