[PATCH] D28985: [Builtin][ARM] Add Thumb1 support for aeabi_c{f,d}cmp.S and dcmp.S

[Zhao, Weiming via llvm-commits]

Hi Renato,

How about changing the #if __ARM_ARCH_ISA_THUMB == 1 To something like 
#if (__ARM_ARCH_6M__ == 1)

Looks like in this case, there is no way to support Thumb for pre-armv6 
arches.

Thanks,

Weiming

On 1/24/2017 1:39 PM, Renato Golin wrote:
> On 24 January 2017 at 19:00, Zhao, Weiming via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
>> Hi Renato,
>>
>> MSR PSR, #imm is available in ARM ISA for  non-M profile.
>>
>> M-profile is Thumb only, which at least supports MSR APSR, <Rn>
> Weiming,
>
> It's ok to have MSR in ARM code, Thumb 2 code and even ARMv6M code,
> but not in Thumb 1 code, because MSR/MRS are 32-bit instructions.
>
> We had this discussion before on the other patch. You cannot assume
> __ARM_ARCH_ISA_THUMB == ARMv6M, because that will be set for anything
> from ARMv4T to ARMv6, plus ARMv6M and ARMv8M.Base.
>
> Thumb 1 code has to assume Thumb 1 targets, not M targets.
>
> cheers,
> --renato

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