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Re: [doc patch] clarify what can appear in SET_DEST
On Tue, Jan 04, 2005 at 02:16:39AM +0100, Steven Bosscher wrote:
> +A set to a REG inside a ZERO_EXTRACT, or SUBREG invokes a
> +read-modify-write We generate both a use and a def and again mark them
> +read/write. */
Well, not all subregs are rmw. A non-paradoxical subreg for which
the number of word_mode units covered by the outer mode is smaller
than that covered by the inner mode, is rmw.
But all the bits to remove SIGN_EXTRACT are ok.