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To: Richard Henderson <rth@redhat.com>
cc: gcc@gcc.gnu.org
Subject: Re: paradoxical subreg problem 
Reply-To: law@redhat.com
From: law@redhat.com
In-reply-to: Your message of Mon, 28 Jan 2002 11:23:30 PST.
             <20020128112330.A25997@redhat.com> 
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Date: Mon, 28 Jan 2002 12:09:00 -0000
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In message <20020128112330.A25997@redhat.com>, Richard Henderson writes:
 > On Mon, Jan 28, 2002 at 11:59:37AM -0700, law@redhat.com wrote:
 > > More correctly, they're allowed between combine and reload inclusively.
 > 
 > I don't think so.
The documentation has allowed this for years.  From rtl.texi:


@cindex combiner pass
@cindex reload pass
@cindex @code{subreg}, special reload handling
Between the combiner pass and the reload pass, it is possible to have a
paradoxical @code{subreg} which contains a @code{mem} instead of a
@code{reg} as its first operand.  After the reload pass, it is also
possible to have a non-paradoxical @code{subreg} which contains a
@code{mem}; this usually occurs when the @code{mem} is a stack slot
which replaced a pseudo register.

 > > And it's the combiner that is creating the paradoxical,
 > 
 > That would be a bug.  A failure to call simplify_subreg or
 > simplify_gen_subreg.
I disagree given the above docs.

jeff
 > 
 > 
 > r~