From: Joern Rennecke <joern.rennecke@superh.com>
To: stevenb@suse.de (Steven Bosscher)
Cc: gcc@gcc.gnu.org
Subject: Re: On -ftrapv vs. libcalls...
Date: Tue, 31 Aug 2004 18:28:00 -0000 [thread overview]
Message-ID: <200408311810.i7VIAES06132@chloe.uk.w2k.superh.com> (raw)
In-Reply-To: <200408221254.28457.stevenb@suse.de> from "Steven Bosscher" at Aug 31, 2004 03:22:49
> Note the __mulvdi3 libcall. At the first opportunity to do so, the
> first jump pass, we collapse it to a normal MULT insn:
Which is actually a bug. basic arithmetic traps on signed overflow with
-ftrapv. There is no place for the trap_if side effect in the REG_EQUAL
note, hence these operations are unsuitable to wrap then with
REG_LIBCALL / REG_RETVAL / REG_EQUAL (at least in their current form).
next prev parent reply other threads:[~2004-08-31 18:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-08-31 13:50 Steven Bosscher
2004-08-31 14:48 ` Zdenek Dvorak
2004-08-31 19:18 ` James E Wilson
2004-09-01 12:12 ` Joern Rennecke
2004-08-31 18:28 ` Joern Rennecke [this message]
2004-08-31 20:21 ` Richard Henderson
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