From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeffrey A Law To: Richard Henderson Cc: ak@muc.de, egcs@cygnus.com Subject: Re: Feature request: ability to describe x86 register halves as contraints. Date: Tue, 30 Jun 1998 14:08:00 -0000 Message-id: <17345.899222932@hurl.cygnus.com> References: <19980630004629.A20825@dot.cygnus.com> X-SW-Source: 1998-06/msg01135.html In message < 19980630004629.A20825@dot.cygnus.com >you write: > On Mon, Jun 29, 1998 at 06:44:04PM +0200, ak@muc.de wrote: > > The only way to do this is to use fixed input registers and hardcode the > > register halves. Unfortunately this adds some compiler version dependencies > > to my code, and also limits the possibilities of the compiler to do other > > optimizations. > > Incorrect: > > b -- print the QImode name of the register for the indicated operand. > %b0 would print %al if operands[0] is reg 0. > w -- likewise, print the HImode name of the register. > k -- likewise, print the SImode name of the register. > h -- print the QImode name for a "high" register, either ah, bh, ch or dh.> And does the compiler just assume that the whole register is trashed since it doesn't ever look at the asm strings? Maybe we're talking about two different issues. jeff