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Re: unshare_all_rtl missed some rtl
- To: Jeffrey A Law <law at cygnus dot com>
- Subject: Re: unshare_all_rtl missed some rtl
- From: Richard Henderson <rth at cygnus dot com>
- Date: Tue, 11 Jan 2000 15:17:23 -0800
- Cc: Geoff Keating <geoffk at cygnus dot com>, gcc-patches at gcc dot gnu dot org, wilson at cygnus dot com
- References: <200001101810.KAA12021@localhost.cygnus.com> <2258.947601424@upchuck>
On Tue, Jan 11, 2000 at 07:37:04AM -0700, Jeffrey A Law wrote:
> This is where I had to stop. Given that those operands are match_dups
> they should be shared. Right?
Needn't be. A match_dup must be equal not eq.
> I'm not 100% sure this is a good thing. The general rule is the predicate
> should allow those operands that are allowed by the processor. For a
> div instruction on the m68k, the first operand is allowed to be a MEM
> expression.
But the ISA allows only one MEM operand to the div insn.
The md pattern is allowing two MEM input operands, plus
a MEM output operand.
r~