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Re: More i386 string ops changes
- To: Jan Hubicka <hubicka at atrey dot karlin dot mff dot cuni dot cz>
- Subject: Re: More i386 string ops changes
- From: Richard Henderson <rth at cygnus dot com>
- Date: Fri, 14 Jan 2000 12:58:48 -0800
- Cc: egcs-patches at egcs dot cygnus dot com
- References: <20000113140936.C24240@atrey.karlin.mff.cuni.cz>
On Thu, Jan 13, 2000 at 02:09:36PM +0100, Jan Hubicka wrote:
> * i386.md (memstr): Use do not use rep stosb for counts divisible by 4
> when optimize_size.
"Use do not use" ?
> ! /* Use formula that gives nonzero result ifif one of the bytes is zero.
> ! This saves three branches inside loop and many cycles. */
"This formula yields a non-zero result iff"
> ! emit_insn (gen_cmpsi_1 (countreg, countreg));
Are you quite sure this won't get optimized away on you?
r~