> > Hi,
> >
> > I have to write a machine description file for a
> chip.
> > For that, i am trying to understand the structure
> and
> > systex of the machine description file of i386.
> >
> > My problem is that why a 'define_insn' with a name
> > that start with '*' is used. Is it used for
> generating
> > RTL insn or for other purpose?
>
> The * in insn name is used for identifying the
> instruction in RTL dumps.
> These are no different from the nameless pattern.
This is what written in the GCC manual.
My problem is that if these expressions are used to
match generated RTL insn then
1. What is the difference between these and the
nameless 'define_insn'?
2. To match RTL code, that code should be generated by
some other 'define_insn'.
But the pattern in define_insn "*..." does not match
with the other patterns in the whole .md file at all.
This means that those RTL insn is not generated by any
RTL expression
in .md file. So what is the need to match them.
Waiting for reply.
Nitin Jain
CSE Dept. (IIT bombay)
> Regards,
> Rakesh
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Nitin Jain,
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