On Wed, Dec 25, 2013 at 10:31 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>> >>>>>>>> cpu_names in i386.c is only used by ix86_function_specific_print >> >>>>>>>> which >> >>>>>>>> accesses it with enum processor_type index. But cpu_names is >> >>>>>>>> defined as >> >>>>>>>> array with enum target_cpu_default index. This patch adds processor >> >>>>>>>> names to processor_target_table and uses processor_target_table >> >>>>>>>> instead >> >>>>>>>> of cpu_names. It removes cpu_names and target_cpu_default. Tested >> >>>>>>>> on >> >>>>>>>> Linux/x86-64. OK to install? >> >>>>>>> >> >>>>>>> Wait a moment, >> >>>>>>> >> >>>>>>> it looks to me that TARGET_CPU_DEFAULT has to be synchronized with >> >>>>>>> const processor_alias_table, so we are able to define various ISA >> >>>>>>> extensions by selecting TARGET_CPU_*. The TARGET_CPU_DEFAULT can then >> >>>>>> >> >>>>>> TARGET_CPU_DEFAULT sets the default -mtune=, not -march=. >> >>>>>> >> >>>>>>> be used to select extensions in the same way as PROCESSOR_* selects >> >>>>>>> tuning for certain processor. >> >>>>>> >> >>>>>> It has been like this for a long time. For x86, TARGET_CPU_DEFAULT >> >>>>>> isn't defined no matter which configure options are used. We can >> >>>>>> change config.gcc to set TARGET_CPU_DEFAULT to proper PROCESSOR_XXX or >> >>>>>> set it to a string "xxx" for processor "xxx". >> >>>>>> But GCC driver always passes -march=/-mtune= to toplev.c so that >> >>>>>> TARGET_CPU_DEFAULT is normally used. >> >>>> >> >>>> I meant to say "TARGET_CPU_DEFAULT isn't normally used." >> >>>> >> >>>>> >> >>>>> Let me rethink this a bit, please do not commit the patch. >> >>>>> >> >>> >> >>> TARGET_CPU_DEFAULT is left over for 32-bit target before --with-arch= >> >>> and --with-cpu= were added. Today, -mtune=xxx -march=xxx are >> >>> always passed to cc1 by GCC driver. If cc1 is run by hand and >> >>> -mtune=xxx -march=xxx aren't passed to cc1, we should do >> >>> >> >>> 1. For 64-bit, it should be the same as -mtune=generic -march=x86_64 >> >>> are passed. >> >>> 2. For 32-bit, it should be the same as -mtune=cpu -march=cpu are >> >>> passed, where "cpu" is the target cpu used to configure GCC, >> >>> like i386 in i386-linux, i486 in i486-linux, .... But there is no i786 >> >>> cpu. i786 is treated as i686. If SUBTARGET32_DEFAULT_CPU >> >>> is defined, it should be the same -mtune=SUBTARGET32_DEFAULT_CPU >> >>> -march=SUBTARGET32_DEFAULT_CPU. >> >>> >> >>> Here is the patch to implement this. >> >> >> >> Let's do one step at a time. So, let's split the patch back to >> >> target/59587 fix: > 2013-12-25 H.J. Lu <hongjiu...@intel.com> > > PR target/59587 > * config/i386/i386.c (struct ptt): Add a field for processor > name. > (processor_target_table): Sync with processor_type. Add > processor names. > (cpu_names): Removed. > (ix86_option_override_internal): Default x_ix86_tune_string > to processor_target_table[TARGET_CPU_DEFAULT].name. > (ix86_function_specific_print): Assert arch and tune < > PROCESSOR_max. Use processor_target_table to print arch and > tune names. > * config/i386/i386.h (TARGET_CPU_DEFAULT): Default to > PROCESSOR_GENERIC. > (target_cpu_default): Removed. > (processor_type): Reordered. OK for mainline and for 4.8 after a few days in mainline. Thanks, Uros.
