[PATCH] Added InstCombine transform for pattern " ((X % Z) + (Y % Z)) % Z -> (X + Y) % Z ".

[Ankur Garg]

Thanks for clarifying that. I understand now, what that undefined behavior is for.

Another thing, in these examples, all three inputs, %x, %y, & %z are known. That is, they are constants. I think such cases wouldn't make it to the transformation. When I was testing the transformation, I tested it with these inputs, the part of the code where the transformation takes place was never reached.
The transformation is useful only when some (or all) bits of any of these inputs are unknown. Otherwise, direct calculation of the expression is done. So, there should be no change in the behavior for the above input, as, in case of this input, this transformation will never be applied.

Thanks.

http://reviews.llvm.org/D5351