------- Additional Comments From kenner at vlsi1 dot ultra dot nyu dot edu
2005-03-24 12:33 -------
Subject: Re: [PR middle-end/20491] combine generates bad subregs
Combine doesn't ensure the subregs it generates are valid. In most
cases, insn recog will reject the invalid subregs, or reload will
some how make them fit, but if the constraint of the insn or the asm
operand is "X", this won't work, so I think we're better off ensuring
we don't ever introduce subregs of non-REGs.
Aside from calling recog combine doesn't check that *anything* it generates
is valid. Why should subregs be different?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20491
