[PATCH] Enable the __ARM_ARCH_EXT_IDIV__ predefine generation on ARM

[Bernie Ogden]

Actually, ignore my first comment. There is a scenario (v7A without
virtualization) where we could have idiv in ARM but not Thumb.
 
> -----Original Message-----
> From: Bernie Ogden [mailto:bogden at arm.com]
> Sent: 18 October 2013 13:07
> To: Silviu Baranga; cfe-commits at cs.uiuc.edu
> Subject: RE: [PATCH] Enable the __ARM_ARCH_EXT_IDIV__ predefine
> generation on ARM
> 
> Hi Siviu,
> 
> clang_ext.diff:
> 
> In principle there should be no targets where we have idiv in ARM but
> not Thumb - but I'm happy with the option as-is because it lets the
> user choose to not generate the instructions per-instruction-set should
> he ever want to. Who are we to declare what users should do? ;)
> 
> (init.c) I guess that we don't want the predefine in these tests
> because the target is Linux, rather than anything to do with the float
> ABIs? If so, is the right place for that test?
> 
> 
> clang_defaults.diff:
> 
> (Targets.cpp): I'm a bit edgy about the check for triples starting with
> armv8. What if some future profile does not have idiv in some
> instrution set? Will it still work if you change that to check for
> armv8a?
> 
> (arm-target-features.c): Is it worth adding tests that the option is a
> nop when it should be (e.g. -target arm -mthumb -mhwdiv=thumb)?
> 
> 
> Regards,
> 
> Bernie
> 
> 
> > -----Original Message-----
> > From: cfe-commits-bounces at cs.uiuc.edu [mailto:cfe-commits-
> > bounces at cs.uiuc.edu] On Behalf Of Silviu Baranga
> > Sent: 17 October 2013 16:02
> > To: cfe-commits at cs.uiuc.edu
> > Subject: [PATCH] Enable the __ARM_ARCH_EXT_IDIV__ predefine
> generation
> > on ARM
> >
> > Hi,
> >
> > The following set of patches enable the generation of the
> > __ARM_ARCH_EXT_IDIV__ predefine
> > for ARM targets which support division instructions. This will fix
> > PR17555.
> >
> > clang_ext.diff:
> > Targets having the hwdiv or hwdiv-arm feature will also the
> > __ARM_ARCH_EXT_IDIV__ predefine.
> >
> > Also adds the -mhwdiv option to modify these features. The arguments
> to
> > this option
> > can be arm/thumb/arm,thumb and indicate in which mode the hardware
> > division instructions
> > are supported (for example passing -mhwdiv=arm means the target
> support
> > hardware division
> > instructions in arm mode but not in thumb mode).
> >
> > clang_defaults.diff:
> > Depends on clang_ext.diff.
> >
> > Sets the default hwdiv/hwdiv-arm features for different targets. The
> > feature is added by
> > default for all AArch32 v8 targets, Cortex-A7, Cortex-A15, swift,
> > Cortex-A53, Cortex-A57,
> > Cortex-R5, Cortex-M4 and Cortex-M3.
> >
> > Please review!
> >
> > Thanks,
> > Silviu
> >
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