[LLVMdev] [PATCH] Apply Thumb2 ROR optimization only when Thumb2 is supported

[Matt Fischer]

Well, I hadn't even built LLVM for the first time until last week, so
I definitely don't have commit access.  :)

Thanks for pushing the fix.  Moreover, thanks for still supporting
those of us who are stuck using silly old ARM11 processors!

On Mon, Jul 2, 2012 at 12:23 PM, Bob Wilson <bob.wilson at apple.com> wrote:
> I went ahead and committed it, along with a basic test case, in svn r159538.
>
> On Jul 2, 2012, at 9:34 AM, Jim Grosbach <grosbach at apple.com> wrote:
>
>> Hi Matt,
>>
>> You're absolutely right, that pattern should definitely have an "only-in-Thumb2" predicate attached.
>>
>> Do you have commit access? Also, if you have a reduced test case, that would be awesome, but the patch is correct as-is even if not.
>>
>> -Jim
>>
>> On Jul 2, 2012, at 8:05 AM, Matt Fischer <mattfischer84 at gmail.com> wrote:
>>
>>> I've been playing around with using LLVM on one of our projects, which
>>> runs on an arm1176jzf-s processor.  When compiling for Thumb, a couple
>>> of the generated assembly files end up with a 'ror.w' instruction,
>>> which is a Thumb2 instruction.  Since arm1176jzf-s doesn't support
>>> Thumb2, the assembler then turns around and barfs on it.
>>>
>>> I don't have any experience with this codebase, but after looking
>>> around for a while, I think I found the culprit--there was a change
>>> back in #130502 which added a peephole optimization to generate that
>>> instruction, but the pattern was not made conditional on being in
>>> Thumb2 mode.  If that's correct, then I believe the attached patch
>>> will fix it (at the very least, it made my specific error go away).
>>> Is this the right fix?
>>>
>>> Thanks,
>>> Matt
>>> <0001-Apply-Thumb2-ROR-optimization-only-when-Thumb2-is-su.patch>_______________________________________________
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