On So, Jan 08, 2012 at 18:56:42 (CET), Reimar Döffinger wrote:
On Sun, Jan 08, 2012 at 06:45:18PM +0100, Nicolas George wrote:
Le nonidi 19 nivôse, an CCXX, Reimar Döffinger a écrit :
I don't know why you ask, but I strongly think that such functionality belongs in gcc and should be triggered by -mcpu=native.
It does belong there indeed, but compiling for ARM is often done by crosscompiling, and AFAIK native does not work in that case.
Yes, but that's the same for looking at cpuinfo... Also note that when using -march=native gcc will print which march setting it translates that to (when using -v or such option in addition).
-march=native will give you binaries that will use all instructions available the build host. Obviously, this cannot work in a cross-compilation setting. Moreover, in a distribution setting this is undesired and pretty harmful as the resulting binary packages will be different, depending on the buildd. The correct fix is to specify the lowest required cpu instruction set to gcc to maximize the number of machines on which the binary will run. If the user wants a higher instruction set, then he should specify that in extra-cflags, for example with -mcpu=native. -- Gruesse/greetings, Reinhard Tartler, KeyID 945348A4