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Re: [PATCH] Fix bug in scheduler's handling of DEBUG_INSNs
- From: Vladimir Makarov <vmakarov at redhat dot com>
- To: Maxim Kuvyrkov <maxim at codesourcery dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 27 Aug 2012 11:47:14 -0400
- Subject: Re: [PATCH] Fix bug in scheduler's handling of DEBUG_INSNs
- References: <CC071817-B032-47F5-8BB5-721DA97F6774@codesourcery.com>
On 08/23/2012 06:08 PM, Maxim Kuvyrkov wrote:
This patch fixes an ICE in sched-deps.c due to a dereference of an empty list.
The problem is in handling of DEBUG_INSNs and its peculiarity of disregarding requests to free dependence lists in certain cases. This patch fixes up an instance of disregarding such a request going wrong. Along the way the patch simplifies add_dependence_list_and_free to an equivalent, but simpler, code.
[Rant: I consider this peculiarity of handling DEBUG_INSNs in sched-deps to be a hack and think that DEBUG_INSNs should be handled differently by creating a new type of dependencies. On the other hand, I understand that such a change is not trivial to implement and that the current implementation has a great argument for it -- that it works.]
May be you are right. Introducing debug_insns was pretty invasive
change and probably their dealing was not implemented in the best way in
some places. On the other hand, debug_insn implementation is a right
approach to achieve more accurate debug info and that is very important
as a lot of tools need more accurate debug info.
Tested on mips-linux-gnu with no regressions. OK to apply?
Ok. Thanks, Maxim.