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Re: PR 17104


Richard Earnshaw wrote:
On Mon, 2004-11-01 at 17:51, Nathan Sidwell wrote:


What is the purpose of LOAD_EXTEND_OP if one has to explicitly wrap
loads with ZERO_EXTENDs?


ZERO_EXTEND has a mode change.  LOAD_EXTEND_OP just tells the compiler
that when loading a register, in say QImode, the physical register that
holds the value will have the top bits set according to the definition
of the EXTEND operation specified.

of course, I forgot that. but it still begs the question as to why expand_move tries to do this, rather than leave it for combine to spot.

nathan

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