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Re: [PATCH] S/390: Fix two issues with the IFUNC optimized mem* routines
- From: Richard Henderson <rth at twiddle dot net>
- To: Andreas Krebbel <krebbel at linux dot vnet dot ibm dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Thu, 06 Sep 2012 07:50:26 -0700
- Subject: Re: [PATCH] S/390: Fix two issues with the IFUNC optimized mem* routines
- References: <20120829104421.GA27985@bart> <503F7FCA.40503@twiddle.net> <503F8328.20703@linux.vnet.ibm.com> <503F95A9.8030604@twiddle.net> <5048A075.9040101@linux.vnet.ibm.com>
On 09/06/2012 06:09 AM, Andreas Krebbel wrote:
> I tried this when implementing the z10 support. Unfortunately in most
> cases using a GOT pointer is faster since all the instructions
> support the <disp>(r12) address format and therefore can directly
> deal with the GOT slot. Not having a GOT pointer requires more
> additional load relatives to be put into the code.
You mean like add, for combining the loaded address with some
other offset? I'm surprised that happens often enough to have
a noticeable effect. Unless there's some secondary effect I'm
not considering?
r~