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[Bug target/13722] [3.4/3.5 regression] [ia64] ICE in push_secondary_reload
- From: "wilson at specifixinc dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 23 Jan 2004 22:55:42 -0000
- Subject: [Bug target/13722] [3.4/3.5 regression] [ia64] ICE in push_secondary_reload
- References: <20040117230657.13722.schwab@suse.de>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From wilson at specifixinc dot com 2004-01-23 22:55 -------
Subject: Re: PR 13722 candidate fix
On Thu, 2004-01-22 at 23:43, Zack Weinberg wrote:
> Under what circumstances should REG_INC notes be tagged onto the insns
> emitted here? It's currently done only for POST_MODIFYs, but this
> patch will generate POST_INC and POST_DEC as well.
I believe the answer is that we need it for all auto-inc addresses. The
REG_INC note indicates that the instruction has another side-effect
besides the sets and clobbers. Any routines that care about instruction
side-effects aren't going to notice the auto-inc address unless the
REG_INC note is there.
The fact that we only do this after reload reduces the chances of a
problem, but the rtlanal.c reg_set_p function needs it, and it is likely
that there is already some code somewhere after reload that directly or
indirectly calls reg_set_p. Thus the REG_INC notes should be added to
be safe.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13722