From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeffrey A Law <law@redhat.com>
To: "John David Anglin" <dave@hiauly1.hia.nrc.ca>
Cc: alan@linuxcare.com.au, gcc-bugs@gcc.gnu.org, gcc-patches@gcc.gnu.org, parisc-linux@thepuffingroup.com
Subject: Re: testcase for hppa64 gcc bug 
Date: Tue, 05 Dec 2000 20:11:00 -0000
Message-id: <17409.976075966@upchuck>
References: <200011091739.MAA07483@hiauly1.hia.nrc.ca>
X-SW-Source: 2000-12/msg00285.html

  In message <200011091739.MAA07483@hiauly1.hia.nrc.ca>you write:
  > For the record, here is my final patch regarding making the arg_pointer
  > eliminable for TARGET_64BIT.  I think the code it generates is correct but
  > it hasn't been extensively tested.  However, I don't recommend it for
  > installation since in comparing the assembler code generated with and
  > without elimination for a couple of test cases, I didn't observe any
  > significant improvement in the code with the patch.  Possibly, the patch
  > implicitly disables elimination when the arg_pointer is needed.
  > 
  > I do find that Alan Modra's ARG_POINTER_INVARIANT patch needs to be install
  > ed
  > to get correct code with his test case.
  > 
  > There is one part of the patch below which I think needs to be installed.
  > That is
  > 
  > 	(call, call_value): Always USE the arg_pointer for TARGET_64BIT.
  > 
  > The use for the arg_pointer needs to be pulled out of the `if (flag_pic)'.
  > 
  > Dave
  > -- 
  > J. David Anglin                                  dave.anglin@nrc.ca
  > National Research Council of Canada              (613) 990-0752 (FAX: 952-6
  > 605)
  > 
  > 2000-11-07  John David Anglin  <dave@hiauly1.hia.nrc.ca>
  > 
  > 	* pa-linux64.h (ARG_POINTER_INVARIANT): Define even when the
  > 	arg_pointer is being eliminated.
  > 	(ELIMINABLE_REGS): Enable elimination of the arg_pointer.
  > 	(INITIAL_ELIMINATION_OFFSET): Revise offsets for arg_pointer.
  > 	* pa.md (mulsi3, divsi3, udivsi3, modsi3, umodsi3 and
  > 	canonicalize_funcptr_for_compare): Put "(reg:SI 26)" inside
  > 	unspec to prevent elimination.
  > 	(call, call_value): Always USE the arg_pointer for TARGET_64BIT.
  > 	Use the new addmovdi3 insn to load the arg_pointer register.
  > 	(addmovdi3 and mov_from_r29_si): New insn and expand which prevent
  > 	r29 from being eliminated in call setups and millicode returns.
I haven't followed this discussion too closely.  Is this patch still needed
after some of the recent changes in how we compute liveness for the argument
pointer?
jeff