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Re: %0 and match_dup in .md
- From: Paul Brook <paul at codesourcery dot com>
- To: Vimal Kumar <askgcc at yahoo dot com>, gcc at gcc dot gnu dot org
- Date: Mon, 5 Jan 2004 12:21:43 +0000
- Subject: Re: %0 and match_dup in .md
- Organization: CodeSourcery
- References: <firstname.lastname@example.org>
On Monday 05 January 2004 12:06 pm, Vimal Kumar wrote:
> As far as I understand, it comes out that operand 0
> and operand 1 are refering to the same expression. So,
> why can't match_dup be used in place of operand 1? In
> fact, I'm unable to figure out the differences between
> the two. I may be missing something very important.
> Please help!!
"(match_dup [...]" from
Basically match_dup matches indicates the same operand is used multiple times.
A "0" constraint matches the same register/object to two different operands.
In the latter case one of the operands may be an autoincrement addressing
mode if the machine supports such things.