On Sun, Apr 21, 2019 at 02:59:13PM -0400, tedheadster wrote: > The gcc mtune documentation is ambiguous about Intel Atom cpus; it > doesn't clearly explain how 32-bit Atom cpus should be handled: > > "atom: Intel Atom CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and > SSSE3 instruction set support" > > ( https://gcc.gnu.org/onlinedocs/gcc-4.5.3/gcc/i386-and-x86_002d64-Options.html > ) 4.5.3 is from 2011. This was fixed in 4.9, released in 2014. https://gcc.gnu.org/r206178 The oldest release that we still support is GCC 7, from 2017. > While most of the Intel Atom processors are 64-bit, there are two > 32-bit models, the Diamondville N270 and N280. > > So does choosing "-mtune=atom" only give you 64-bit code? If so, > should we add a note to choose an alternate "-mtune=XXX" for 32-bit > Atom processors? Patches are welcome, of course. Apparently Diamondville is quite close to Bonnell. Not sure how useful that is, if -m32 works, or if you need a different -mcpu with separate -mtune. Segher
