[PATCH] gas/arm: Misses deprecated IT instruction warning for ARMv8

[Richard Earnshaw]

On 13/06/14 16:55, Nicholas Clifton wrote:
> Hi Jiong,
> 
>> given code:
>>
>> .thumb
>> .syntax unified
>>
>> it eq
>> addeq sp, sp, #12
>>
>> assembled with -march=armv8-a -mthumb, gas fails to warn
>> that this is a deprecated form.
> 
> Where is this deprecation specified ?   Please can you give a reference 
> so that I can check it ?
> 
> Cheers
>    Nick
> 
> 

It's in section F6.2 of the v8 ARM ARM:

Registered users can get a copy from here:

http://arminfo.emea.arm.com/help/topic/com.arm.doc.ddi0487a.b/DDI0487A_b_armv8_arm.pdf

But this doesn't look right, since the instructions you need to match
don't follow this pattern:

+  { 0x00dd, 0x7fff, N_("ADD/SUB sp, sp #imm") },

Specifically SUB SP is 0b101100001xxxxxxx
and ADD SP is 0b101100000xxxxxxx.

Iff your mask is right, it needs a comment to explain why.

R.