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Re: Arch-independent double-word clz expansion and a few other tweaks for bitscanning
- From: Rask Ingemann Lambertsen <rask at sygehus dot dk>
- To: Zack Weinberg <zack at codesourcery dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Sat, 11 Aug 2007 11:05:50 +0200
- Subject: Re: Arch-independent double-word clz expansion and a few other tweaks for bitscanning
- References: <46BD5B0D.403@codesourcery.com>
On Fri, Aug 10, 2007 at 11:45:33PM -0700, Zack Weinberg wrote:
> ==================================================================
> --- config/i386/i386.md (revision 127388)
> +++ config/i386/i386.md (local)
> @@ -14583,98 +14583,16 @@ (define_insn "leave_rex64"
...
> +(define_insn "ctzsi2"
> + [(set (match_operand:SI 0 "register_operand" "=r")
> + (ctz:SI (match_operand:SI 1 "nonimmediate_operand" "rm")))
> + (set (reg:CCZ FLAGS_REG)
> + (compare:CCZ (match_dup 1) (const_int 0)))]
Usually this sort of insn has the (set (reg:CCx FLAGS_REG) ...) part
first because that's how combine wants it. Likewise with the other ones you
added.
--
Rask Ingemann Lambertsen