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Re: [PATCH] Omit frame pointer and fix %ebp by default on x86 (take3)
- From: Roger Sayle <roger at eyesopen dot com>
- To: Giovanni Bajo <giovannibajo at libero dot it>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Sun, 15 Aug 2004 19:25:37 -0600 (MDT)
- Subject: Re: [PATCH] Omit frame pointer and fix %ebp by default on x86 (take3)
On Mon, 16 Aug 2004, Giovanni Bajo wrote:
> > The second point is that we update both fixed_regs and call_used_regs.
> > The cause of the failures mentioned above is caused by the fact that
> > reload assumes that call_used_regs is a superset of fixed_regs, and
> > so just modifying fixed_regs leads to a few additional testsuite
> > failures.
>
> So, why don't you add a runtime sanity check in debug builds so that
> others won't be fooled by this?
Good idea. I'll prepare an ENABLE_CHECKING patch. Unlike the patch
you cite, testing that fixed_reg_set is a subset of call_used_reg_set
isn't something that can be optimized away at compile-time.
Roger
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