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Re: [PATCH] Re: Checking out PR4483 (constant overflow on PPC, problems compiling Linux kernel)


    One of the reasons against it may be that *operations* need to know
    the mode of their results. In this case, we have a PLUS operation in
    SI mode.  The compiler should know that information. What the mode of
    the operand is does not really matter here. We have two mathematical
    quantities x and y and we want to do a certain operation on them. This
    operation can conceptually be separated in a mathematically exact part
    (the familiar notion of +) and a rounding/truncating step. This is
    similar to floating-point arithmetic.

Yes, this is what I was trying to say: thanks.  Note, however, that the
analogy to FP breaks down here slightly because we *do* have modes for FP
constants.  But the reason for that is that the *representation* differs
between modes, not the values.


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