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Re: [new-ra] DF_REF_REG_CLOBBER related bugfix
- From: Michael Matz <matz at suse dot de>
- To: Denis Chertykov <denisc at overta dot ru>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Fri, 24 Oct 2003 19:24:11 +0200 (CEST)
- Subject: Re: [new-ra] DF_REF_REG_CLOBBER related bugfix
On 24 Oct 2003, Denis Chertykov wrote:
> w1 - web without conflict_list (now w1 got stack slot)
> w2 - 'corresponding web' (web which connected to w1 by move) and
> havn't a conflict with w1 because of w1->usable_regs is empty
> i1 def w1
> i2 move w2 <= w1
> i3 def w2, use w2
> i4 use w2
> i5 use w1
> coalesce_spill_slot will try to coalesce w1 with w2.
I think the condition for coalescing them there simply should be, that
w2's color is actually acceptable by w1->usable_regs. This will also
avoid coalescing the two, but would catch more cases (for instance it
could happen in the future, that webs have usable_regs empty, but
nevertheless have a conflict_list).