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Re: UNSPEC vs. CLOBBER followed by (set (subreg ...))
- To: Geoff Keating <geoffk at cygnus dot com>
- Subject: Re: UNSPEC vs. CLOBBER followed by (set (subreg ...))
- From: Richard Henderson <rth at cygnus dot com>
- Date: Mon, 24 Jan 2000 21:15:36 -0800
- Cc: gcc-patches at gcc dot gnu dot org
- References: <200001242038.MAA21099@localhost.cygnus.com>
On Mon, Jan 24, 2000 at 12:38:39PM -0800, Geoff Keating wrote:
> I don't believe that a CLOBBER followed by (set (subreg ...)) will be
> optimized worse than an UNSPEC...
In fact I believe the opposite to be true. You should get better
code from the unspec than the subreg.
> (insn 24 22 26 (set (mem:DI (plus:SI (reg:SI 31 r31)
> (const_int 8 [0x8])) 0)
> (reg:DI 84)) 442 {*movdi_32} (insn_list 22 (nil))
I thought you didn't allow DImode values in the FP regs?
r~