Messages in this thread | | | From | Måns Rullgård <> | Subject | Re: [RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions | Date | Tue, 24 Nov 2015 12:10:02 +0000 |
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Russell King - ARM Linux <linux@arm.linux.org.uk> writes:
> On Tue, Nov 24, 2015 at 11:38:53AM +0100, Arnd Bergmann wrote: >> I suggested using -mcpu=cortex-a15 because there are old gcc versions >> that don't know about -march=armv7ve or -march=armv7-a+idiv yet, but >> that do understand -mcpu=cortex-a15. > > That's not all. The bigger problem is that there are toolchains out > there which accept these options, but do _not_ support IDIV in either > ARM or Thumb mode. I'm afraid that makes it impossible to add this > feature to the mainline kernel in this form: we need to run a test > build to check that -march=armv7ve or what-not really does work > through both GCC and GAS.
If the compiler accepts the option but doesn't actually emit any div instructions, is there any real harm?
-- Måns Rullgård mans@mansr.com
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