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Re: About the unnamed insn defined in the machine.md
- From: Ian Lance Taylor <iant at google dot com>
- To: "redriver jiang" <jiangpeople at gmail dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: 03 Mar 2007 10:59:23 -0800
- Subject: Re: About the unnamed insn defined in the machine.md
- References: <338f53fb0703030624i3eee3773rfb541bda07149f55@mail.gmail.com>
"redriver jiang" <jiangpeople@gmail.com> writes:
> Hello, recently I am porting the GCC backend to a DSP. The GCC
> Internals document says that the unnamed insns are used to translate
> RTL insns to the assembler insns, but I find that the unnamed insn
> patterns can be used in combine phase to combine insns by reading the
> "*arith_shiftsi" insn pattern in arm.md file..This "*arith_shiftsi"
> insn pattern is used to combine the "plus insn" and "shift insn" into
> "add rd,Rn,rm,shift immediate_operand".Is my understanding correct?
Yes.
Ian