From: "Ulrich Weigand" <Ulrich.Weigand@de.ibm.com>
To: gcc@gcc.gnu.org
Subject: RFA: Ada variable-sized objects, bit_size_type == TImode, and divti3
Date: Thu, 20 Mar 2003 21:55:00 -0000 [thread overview]
Message-ID: <OFBAB4CE9A.60EE15CF-ONC1256CEF.0072786F@de.ibm.com> (raw)
Hello,
Ada builds are currently failing on s390x due to missing __divti3.
Now, I guess we could add 128-bit division routines to libgcc.
However, the question is whether this should really be needed.
What appears to happen is that the Ada source in question defines
a variable-sized object with non-standard alignment requirements,
and Ada reflects this by building a DECL_SIZE_UNIT tree containing
various mult_expr and div_expr nodes. As alignment is counted in
bits, those have type bit_size_type, which on 64-bit platforms
corresponds to TImode. When expanding that tree, the backend emits
calls to __divti3.
However, I'm wondering:
- does bit_size_type really need to be TImode
- if so, shouldn't these special cases be implemented more efficiently
somewhere (we divide by an integer constant 8 here)
- in general, are we really supposed to need TImode division
How does this work on other 64-bit platforms?
Mit freundlichen Gruessen / Best Regards
Ulrich Weigand
--
Dr. Ulrich Weigand
Linux for S/390 Design & Development
IBM Deutschland Entwicklung GmbH, Schoenaicher Str. 220, 71032 Boeblingen
Phone: +49-7031/16-3727 --- Email: Ulrich.Weigand@de.ibm.com
next reply other threads:[~2003-03-20 20:59 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-20 21:55 Ulrich Weigand [this message]
2003-03-20 22:31 ` Richard Henderson
2003-03-20 23:18 ` Geert Bosch
2003-03-21 0:00 ` Janis Johnson
2003-03-20 22:35 Ulrich Weigand
2003-03-20 23:44 ` Richard Henderson
2003-03-21 0:25 ` Neil Booth
2003-03-21 1:58 ` Ulrich Weigand
2003-03-21 7:46 ` Richard Henderson
2003-03-21 16:27 ` Ulrich Weigand
2003-03-21 20:25 ` Ulrich Weigand
2003-03-21 2:09 Ulrich Weigand
2003-03-24 11:08 Richard Kenner
2003-03-31 20:16 Richard Kenner
2003-04-01 19:26 Ulrich Weigand
2003-04-01 22:53 Richard Kenner
2003-04-02 15:36 Ulrich Weigand
2003-04-02 15:36 Richard Kenner
2003-04-02 15:43 Ulrich Weigand
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