[Bug target/55426] New: gcc.target/arm/neon-vld1_dupQ.c ICEs on armeb

["mmatti.gcc at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55426

             Bug #: 55426
           Summary: gcc.target/arm/neon-vld1_dupQ.c ICEs on armeb
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mmatti.gcc@gmail.com
                CC: christophe.lyon@st.com, ramana.radhakrishnan@arm.com
              Host: Scientific Linux 6.3
            Target: arm big-endian
             Build: Scientific Linux 6.3


Hi,

I have encountered a following ICE on arm big endian target

{{{
neon-vld1_dupQ.c: In function ‘main’:
neon-vld1_dupQ.c:24:1: error: unrecognizable insn:
(insn 94 93 31 (set (subreg:DI (reg:V2DI 95 d16 [orig:137 D.14400 ] [137]) 0)
        (subreg:DI (reg:V2DI 95 d16 [orig:137 D.14400 ] [137]) 8))
/home/armbe/toolchain/armeb-tools/bin/../lib/gcc/armeb-none-linux-gnueabi/4.7.0/include/arm_neon.h:8214
-1
     (nil))
neon-vld1_dupQ.c:24:1: internal compiler error: in extract_insn, at
recog.c:2123
Please submit a full bug report,
}}}

My initial investigation shows that the following patch (split insn)
http://gcc.gnu.org/ml/gcc-patches/2012-05/msg01131.html is causing
this failure.
I think the CANNOT_CHANGE_MODE_CLASS macro is present and also plays a
role in not allowing the mov of DImode in this case.

If I revert the patch then I do not encounter this problem.

I can propose a solution, which may fix this problem.

In case of little endian the compiler generates,

{{{
insn 93 26 94 (set (reg:DI 95 d16 [orig:137 D.14400 ] [137])
        (vec_duplicate:DI (mem:DI (reg/f:SI 2 r2 [155]) [0 *(const
__builtin_neon_di[1] *) __a_5+0 S8 A64])))
/home/armbe/toolchain/arm-tools/bin/../lib/gcc/arm-montavista-linux-gnueabi/4.7.0/include/arm_neon.h:8214
1606 {neon_vld1_dupdi}
     (nil))
        vld1.64 {d16}, [r2:64]  @ 93    neon_vld1_dupdi [length = 4]
(insn 94 93 31 (set (reg:DI 97 d17 [ D.14400+8 ])
        (reg:DI 95 d16 [orig:137 D.14400 ] [137]))
/home/armbe/toolchain/arm-tools/bin/../lib/
}}}

But incase of big endian the vmov\t%f0, %e0 is missing there is no
pattern in the neon.md file.
Adding this may solve the problem. Something like this

(define_insn "*neon_subreg_di"
  [(set (match_operand:DI 0 "s_register_operand" "=w")
       (match_operand:DI 1 "s_register_operand" "w"))]
 "TARGET_NEON"
 "vmov\t%1, %0"
)

Kindly comment on this patch or could you please help me with the 
pointers to solve this problem.

Regards,
Manjunath S Matti.