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Re: PATCH: Use -mtune= instead of -mcpu=
- From: Steve Munroe <sjmunroe at us dot ibm dot com>
- To: "H.J. Lu" <hjl at lucon dot org>
- Cc: GNU C Library <libc-alpha at sources dot redhat dot com>
- Date: Sun, 16 Sep 2007 16:56:39 -0500
- Subject: Re: PATCH: Use -mtune= instead of -mcpu=
libc-alpha-owner@sourceware.org wrote on 09/14/2007 01:14:24 PM:
> I believe all required gcc support -mtune= and -mcpu= is deprecated.
>
No this is true only for Intel, PowerPC still uses -mcpu. This change would
disable the existing -with-cpu= optimization available for PowerPC.
The equivalent for Intel is -march= because we want to select source
optimizations based on ISA version or processor extention. -mtune is
implied, but can and should be specified separately (via CFLAGS).
If you want to change this you need to condition use of -mcpu vs -march
based on $machine or $base_machine.
>
> H.J.
> ----
> 2007-09-14 H.J. Lu <hongjiu.lu@intel.com>
>
> * Makeconfig (cflags): Use -mtune= instead of -mcpu=.
>
> --- Makeconfig.tune 2007-07-23 11:02:47.000000000 -0700
> +++ Makeconfig 2007-09-14 10:44:45.000000000 -0700
> @@ -642,7 +642,7 @@ ifeq "$(strip $(+cflags))" ""
> +cflags := $(default_cflags)
> endif # $(+cflags) == ""
>
> -+cflags += $(addprefix -mcpu=,$(with-cpu)) $(+gccwarn)
$(+merge-constants)
> ++cflags += $(addprefix -mtune=,$(with-cpu)) $(+gccwarn)
$(+merge-constants)
> +gcc-nowarn := -w
>
> # Don't duplicate options if we inherited variables from the parent.
Steven J. Munroe
Linux on Power Toolchain Architect
IBM Corporation, Linux Technology Center