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Re: Feature request: ability to describe x86 register halves as contraints.


Jeffrey A Law wrote:
> First there'd have to be a way to describe hi/lo halves of registers
> in RTL.  I'm not aware of any such mechanism.

Couldn't (subreg:QI (reg:HI 0) 1) or (subreg:QI (reg:SI 0) 1) be used to
represent AH?  Trouble is, someone will have to teach egcs to use such
constructs (I'm not well versed on the operation of trees yet,
especially tree->rtl conversion)

Also, how difficult would it be to add eiter a new machine mode or a new
flag/interpretation of existing flags to represent halves of registers?

Bill
-- 
Leave others their otherness


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