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

[Renato Golin via llvm-commits]

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