Re: How to eliminate redundant constant move instructions

On 2011-11-02, George Neuner <gneuner2@comcast.net> wrote:
> Yes. But the compiler can't count on register renaming ... it can see
> only the architectural named registers. If the code in question had
> copied Rx-> Ry then renaming would have been possible, but instead the
> code performed a constant load to each register. No possibility of
> rename sharing there.


If the register holds a value that is used, but not clobbered, then renaming is
moot. The two blocks of code both depend on rx being zero, and so nothing is
achieved by splitting the instruction set register into two physical registers.

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